NYSGA 2022
New York State Geological Association
93rd Annual Meeting
Field Trip Guidebook
Hosted by
Geological Sciences Program at the State University of New York at Oswego
Oswego, NY, 13126
Edited by
David W. Valentino
Published by the
www.nysgaonline.org

A1 The Salt Of the Earth And the Soul Of the Silurian Sea - the Upper Silurian Syracuse Formation And Adjacent Formations in Central NY
JON S. FOX
Department of Atmospheric and Geological Sciences
State University of New York at Oswego
Oswego, NY 13126
Introduction
The Syracuse Formation occurs within the Upper Silurian Salina Group in the northern Appalachian Basin. Considerable attention has been paid to this formation in the past based on the occurrence of economic quantities of rock salt (halite) and gypsum, which are of significant importance to the historical and economic development of the region. In addition to rock salt and gypsum, the Upper Silurian rocks of central New York State contain a wide variety of interesting and important geological characteristics. While considerable attention has been paid to the occurrence and distribution of halite and gypsum, less attention has been paid to the sedimentary petrology, geochemistry, and paleontology of the Syracuse Formation. The same is generally true for the underlying Vernon Formation and the overlying Camillus Formation. A significant reason for this may be the general softness/lack of resistance of the various lithologies to the processes of mechanical and chemical weathering, coupled with relatively low relief topography in the central New York outcrop belt, which collectively result in limited numbers of (and quality of) rock outcrops available for study. During recent field work, the author has noted that a significant number of the outcrops previously described in the published scientific literature are currently covered or are otherwise inaccessible due to weathering, subsequent land development activities, or other property ownership or management considerations. Luckily, we can supplement the relative scarcity of accessible rock outcrops by examining rock cores through these formations collected from the subsurface. The New York State Museum/Geological Survey maintains (and makes available for study) a collection of rock cores and well drill cuttings from across the state. Rock cores and drill cuttings are typically obtained by the State Museum from oil and gas exploration and development, salt solution mining, or construction project activities.
The goal of this field trip is to provide participants with an opportunity to visit a few of the more accessible outcrops remaining in central New York State to provide a general introduction to the lithological and paleontological characteristics of these fascinating formations. The locations of stops are shown in Figure 1. We will also stop at Cargill’s Cayuga Salt Mine, a currently active salt mine located near Lansing, New York, to receive a presentation from the mine’s manager (Mr. Shawn Wilzynski) and his staff regarding the mine’s geology and operations. Cargill’s presentation will be at the surface and we will not be visiting subsurface portion of the mine during this field trip. We are very grateful to Cargill, Mr. Wilzynski, and his team for their willingness to welcome us to their facility, provide us with a presentation on their operations, and show us some rock samples from their mine. Cargill’s assistance to our group will contribute significantly to the continuing professional education of current and future professional geologists in New York State.

1A: THE SALT OF THE EARTH AND THE SOUL OF THE SILURIAN SEA - THE UPPER SILURIAN SYRACUSE FORMATION AND ADJACENT FORMATIONS IN CENTRAL NEW YORK

Stop 1 Meeting Point: Shove Park, Town of Camillus, Onondaga County,
We’ll walk together from the meeting point upstream through the woods along Geddes Brook to an outcrop which exposes the upper portion of the Syracuse Formation (Upper Dolomite Member) and the overlying Camillus Formation (mostly covered). The contact between these two formations is gradational and mostly covered at this location, but there is good exposure of the Upper Dolomite Member here. Relatively resistant dolostone beds and less resistant argillaceous dolostones below form a low-relief waterfall near the top of the Upper Dolomite Member.

Stop 2: Nose Hill, Town of Camillus, Onondaga County,
This stop provides an excellent opportunity to observe stratigraphic units in the upper portion of the Syracuse Formation, including the Upper Clay and Upper Dolomite members. The contact with the base of the overlying Camillus Formation is also exposed. The Middle Dolomite Member of the Syracuse Formation is also present in this outcrop; however, it is mostly covered by talus near the base of the outcrop.

Stop 3: Cargill Cayuga Salt Mine, Town of Lansing, Tompkins County,
Cargill Deicing Technology operates this mine, providing customers with deicing technology and road salt that saves lives, enhances commerce, and reduces environmental impact.
In 1915, John Clute organized the Rock Salt Corporation on Portland Point in Lansing. In 1916, a shaft was sunk to -1500 feet, but the salt was of poor quality. By 1918 the mine was still not producing well and was shut down. In 1921, Frank L. Bolton and John W. Shannon bought the mine and further sank the shaft to ~ 2000 feet to a better vein of salt which was 99% pure. The operation was managed by Frank Bolton, and then his wife Lucie when he died. The mine was operated by the Cayuga Rock Salt Company, Inc. until Cargill acquired the mine in 1970 and modernized the mine with new beltlines for salt haulage, ventilation updates, a new shaft, and new diesel-powered equipment. The mine produces approximately 2 million tons of road salt annually that is shipped to more than 1500 locations throughout New York State and the northeastern United States. The mine employs more than 200 full-time employees in operations, maintenance, engineering, finance, management and support positions.
Currently, the mine is advancing north up Cayuga Lake and is approximately one mile past Taughannock Point. The salt is mainly sold in the road deicing market in the Northeast (including New York, Vermont, and Pennsylvania) but is also sold under the Diamond Crystal name as residential deicing salt.
The Cayuga Mine operates under a Mined Land Reclamation Permit issued by the DEC in 1975. Permit renewals were approved in 1985, 1997, 2003, 2007, 2012, 2019 and modifications were approved in 2013, 2015 and 2017. In each case, DEC determined that there would be no significant adverse environmental impact from mining.
In the mid-1990s, Cargill undertook a thorough environmental assessment of the region to verify Cargill’s understanding of the geology. This work has served as a critical foundation for the continued evaluation and study of mine stability and operations. Data collected through these continuing studies is regularly evaluated and verified by numerous third-party experts employed by DEC and Cargill.
Since 2002, the Cayuga Mine has submitted an annual report on the status of special conditions outlined in the permit. The primary focus is on mine stability, three-year mine plans and water management. DEC utilizes the services of Dr. Vincent Scovazzo, an internationally recognized mine stability expert from the John T. Boyd Company, for mine stability review and participation in the annual on-site visit and inspection of the mine. Over the years, Cargill has relied on several similarly credentialed experts to assist its own mine stability and other technical evaluations. Each year Cargill performs an internal risk review with leaders to evaluate and manage the risks associated with mining.
In addition, the federal Mine Safety & Health Administration (MSHA) oversees mine safety such as adequacy of underground ventilation and emergency access. MSHA inspects the mine every calendar quarter. Each of these inspections typically lasts six to eight weeks.
The mine’s manager, Mr. Shawn Wilczynski, and his staff, will provide us with a presentation on the mine’s geology and operations. I have requested that they also show us specimens of rock salt and other lithologies from the Syracuse Formation from their mine. The total thickness of the Syracuse Formation at the mine exceeds 800 feet, including a total salt thickness exceeding 400 feet. The mine historically has produced salt from either the F1 unit (No. 4 Salt) or the D unit (No. 6 Salt) of the Syracuse Formation. Stratigraphically, the F1 unit is interpreted to occur within the Lower Clay Member and the D unit is interpreted to occur within the Transition Member of the Syracuse Formation (Figure 3). Cargill is currently mining the D unit (No. 6) salt.

Stop 4: Osborne Road, Town of Sullivan, Madison County,
The Middle Dolomite Member of the Syracuse Formation is well exposed at this locality, and this locality reportedly is one of the better locations in central New York to find fossils from the Camarotoechia zone (Leutze, 1956). The fossils are generally well preserved in gray shale near the base of the Middle Dolomite Member. The fauna is concentrated in the lowermost few feet of the member and fossils become rare higher in the section. Wavy, parallel bedding and lamination, which are locally discontinuous, are commonly observed at this locality.

Stop 5: Manlius Center, Town of Manlius, Onondaga County,
We will walk from the parking lot north along the former railroad bed for approximately one tenth of a mile. The former railroad bed is somewhat overgrown with vegetation, but there are excellent exposures of the Syracuse Formation, particularly on the eastern hillside. Although there is no formal type section designated for the Syracuse Formation and the lowermost member of the formation (the Transition Member) is not exposed here, this large outcrop was cited by Leutze (1959) as an ideal reference section for the Syracuse Formation given its accessibility, relative completeness, and clarity of the stratigraphic section. The exposed portion of the Syracuse Formation at this location is approximately 64 feet thick and the stratigraphic units exposed here include (in ascending order) the Middle Dolomite Member (37 feet thick), the Upper Clay Member (11 feet thick), and the Upper Dolomite Member (16 feet thick). Talus typically obscures much of the Middle Dolomite Member. Access to exposed rock can be facilitated by digging “steps” in the talus using a camping shovel.

Stop 6: Intersection of NY Route 298 and I-481, Town of DeWitt, Onondaga County
Our last stop on this trip will be a brief stop at a small exposure of the Vernon Formation. The Vernon Formation in central New York is often moderate red (5R 5/4; see Figure 37); however, certain intervals of the formation (particularly the middle portion in central New York) are often pale green (5G 7/2) as seen at this stop (Figure 38). Given its softness and lack of resistance to weathering, significant outcrops of the Vernon Formation are rare, particularly in areas of relatively low topographic relief.

A2 Igneous And Metamorphic Rocks Of the Black And Moose River Valleys, Western Adirondack Highlands, NY
Robert S. Darling
Geology Department
SUNY College at Cortland
Cortland, NY 13045
Introduction
The Black and Moose Rivers, the largest rivers in the western Adirondack Highlands, have exposed numerous Middle Proterozoic metamorphic rocks, with the former largely paralleling the unconformity between Ordovician sedimentary rocks of the Tug Hill Plateau and Proterozoic gneisses of the Adirondack Highlands (to the east; Figure 1). Consequently, the region has attracted sedimentologists, stratigraphers, paleontologists, and metamorphic and igneous petrologists. Our trip, however, will focus almost entirely on the Middle Proterozoic meta-igneous and meta-sedimentary rocks.
The Adirondack region of northern New York State is a roughly circular dome of high-grade metamorphic and igneous rocks that form a southeast extension of the Grenville Province in Canada (inset of Figure 2). The Adirondack Highlands comprise mostly meta-igneous rocks (anorthosites, charnockites, mangerites, gabbros, and granites) whereas the Adirondack Lowlands comprise mostly meta-sedimentary rocks (calc-silicates, marbles, metapelites). The Lowlands are separated from the Highlands by the Carthage-Colton mylonite zone (CCMZ), which shows extensive down-to-the-northwest relative motion from the collapse of the Ottawan phase of the Grenville Orogenic cycle (Rivers, 2008). The CCMZ is a metamorphic age and facies boundary as well, with upper amphibolite facies and Shawinigan age (1190-1140 Ma) metamorphic rocks in the Lowlands and granulite facies and Ottawan age (1090-1020 Ma) metamorphic rocks in the Highlands (Darling and Peck, 2016).
As shown in Figure 2, Middle Proterozoic rocks in the western Adirondacks are characterized by mostly charnockites and granites, with lesser amounts of amphibolite and meta-sedimentary rocks (metapelites and calcsilicates). Radiometric dating in the area has largely concentrated on the Lyon Mtn granite (McLelland et al., 2001, 2002b) and surrounding metapelites (Florence et al., 1995). The radiometric dates of zircon fall into two general categories, those associated with the Ottawan phase of the Grenville Orogeny (ca. 1050-1090 Ma) and those associated with earlier anorthosite-mangerite-charnockite-granite (AMCG) magmatism (1145-1160 Ma).
Metapelitic rocks in the western Adirondack Highlands have been the focus of three metamorphic studies (Florence et al., 1995; Darling et al., 2004; Darling, 2013) and pressure-temperature (PT) conditions of >780°C, 6.0 ± 0.5 kbar near Port Leyden, NY, and 830-870°C and 6.0-7.2 kb near Moose River, NY, have been determined. These PT conditions are well into the granulite-facies, but the lower than average pressures reported by Florence et al. (1995) and Darling (2013) suggest mid-crustal burial depths with an elevated geotherm. The metamorphic temperatures determined in the aforementioned studies are considerably higher than those projected by Bohlen et al. (1985) for the western Adirondacks. A summary of Adirondack metamorphic conditions is provided by Darling and Peck (2016), and new evidence of ultrahigh temperature metamorphism (UHT, >900°C) has recently been described in the central Adirondacks by Shinevar et al. (2021), Ferrero et al. (2021), and Metzger et al. (2022).
On this trip, we will visit a number of unusual meta-igneous and meta-sedimentary rock types.

A2 IGNEOUS AND METAMORPHIC ROCKS OF THE BLACK AND MOOSE RIVER VALLEYS,
WESTERN ADIRONDACK HIGHLANDS, NY

Meeting Point
Parking lot of the Edge Hotel, Route 12, Lyons Falls, NY.
The Edge Hotel is located 40 miles north of Utica on Route 12

Stop 1 Parking

STOP 1. Ordovician spheroidal weathering in Middle Proterozoic gneiss
Walk down to the exposures of pink feldspathic gneiss along Roaring Brook. Here fractured bedrock contains very good examples of spheroidal weathering preserving between the fractures sets (Figure 3). The spheroidal weathering is characterized by closely spaced (3-4 mm) bands of iron hydroxide, the bands extending into the gneiss a few centimeters from the fracture sets. Microscopically, the bands are characterized by fine-grained iron-hydroxide, calcite, chlorite, and possibly serpentine. Locally, the bands are filled with medium-grained calcite, suggesting open fracture deposition.
From this location, walk upstream about 30 meters and observe the lowermost red and green sands and pebble conglomerates of the Pamelia Formation (Middle Ordovician) resting directly on top of Middle Proterozoic gneiss. This is the widely known Knox Unconformity and represents nearly 600 million years of missing rock record. The unconformity is easily observed in the stream bed. Spheroidal weathering also occurs directly below the nonconformable contact, but is observed only during low water levels (normally late summer). The spheroidal weathering directly below the nonconformity and ±30 meters downstream (location of Fig. 3) are the only locations where it has been observed. Both are located within one vertical meter of the nonconformity. Exposures of felsic gneiss farther downstream, which are a few meters below the projection of the unconformity, show little or no evidence of spheroidal weathering. The proximal relationship between the nonconformity and spheroidal weathering is interpreted as evidence of Ordovician-age chemical weathering. Middle Ordovician time, therefore, was likely tropical or sub-tropical, which is consistent with paleomagnetic studies (Niocaill, et al., 1997).
Because the closely spaced bands of iron hydroxide (in the spheroidal weathered portion of the gneiss) contain chlorite, the rocks must have been buried to “chlorite-grade” depths following middle Ordovician deposition. This is interpreted to have occurred during the late Paleozoic Alleghanian Orogeny (Isachsen et al., 1991). Consequently, the chlorite here cannot be associated with retrograde metamorphism that occurred during exhumation of Middle Proterozoic rocks following the Grenville Orogeny.

STOP 2. – Port Leyden nelsonite
This is one of two occurrences of nelsonite in New York State (Darling and Florence, 1995). The other occurs near Cheney Pond, 110 km to the northeast, in the High Peaks region of the Adirondacks (Kolker, 1980; 1982). At Port Leyden, the nelsonite occurs as a dike about 3 to 4 meters wide and is traceable for about 30 meters on the surface. The host rock is metapelitic gneiss comprising K-feldspar, quartz, garnet, biotite, sillimanite and spinel.
Nelsonites are unusual igneous rocks comprising apatite and Fe-Ti oxides such as ilmenite, or magnetite and rutile. They are one of the few igneous rocks on Earth that have little or no silicate minerals. The Port Leyden nelsonite has 32-50% magnetite, 8-15% ilmenite, 30-45% apatite, and 5-11% pyrite (Darling and Florence, 1995). Chlorite is present as well and easily observed in hand specimens, whereas garnet, zircon and monazite are best observed in thin section. The pyrite commonly defines planar bands and lenses in what could be described as a foliation.
A characteristic feature of nelsonite is its overall, fine-grained texture compared to other rocks of the anorthosite suite (A. Philpotts, personal communication,) see Figure 4. However, ilmenite in the Port Leyden nelsonite actually forms much larger, oikocrystic grains up to 5 cm across (Figure 5). Although hard to observe in Figure 4, all of the ilmenite shown is actually part of one larger grain. Oikocrysts are large crystals that enclose smaller crystals to form a poikilitic texture. At Port Leyden, the ilmenite fills voids between millimeter scale apatite and magnetite grains (Figure 4). Nearly all ilmenite in the Port Leyden nelsonite is oikocrystic and is best observed by reflections from the (0001) parting on freshly broken or cut surfaces (Figure 5). Ilmenite also occurs as oxy-exsolution lamellae in magnetite (Fenner et al., 2018).
It is tempting to infer that the ilmenite oikocrysts have a late igneous origin, but Duchesne (1996) argues against late liquids with a pure ilmenite composition. Although the texture is indicative of late crystallization, the origin of interstitial ilmenite could be the result of post-igneous deformation instead (Duchesne, 1996).
Nelsonites are normally associated with anorthosite-suite rocks (like at Cheney Pond) and there are two proposed theories on their origin. They are believed to form by either magmatic immiscibility (Philpotts, 1967; 1981) or by cumulate processes (Dymek and Owens, 2001; Duchesne and Liégeois, 2015), but in both cases the source rocks are either oxide-apatite gabbro norites or jotunites of the anorthosite suite. Neither of these two rocks occurs within the vicinity of Port Leyden, so the parent rock of the Port Leyden nelsonite has thus far not been identified. It is conceivable that the parent rocks once existed in the Port Leyden area and were eroded away. This is plausible because Philpotts (1981) suggests that nelsonites actually intrude downward in the crust due to their high liquid density (∼4.0 gms/cm3). It is also possible that anorthosite-suite rocks currently located near Carthage, NY (∼50 km to the north-northwest; see Buddington, 1939) could be a potential source rock as the Adirondack Lowlands once existed structurally on top of the Adirondack Highlands and slid in a NW direction along the CCMZ late in the history of the Grenville Orogeny (Rivers, 2008). This would require greater than 50 km of horizontal displacement along the CCMZ, however. Lastly, the most likely and nearest source rocks (stratiform anorthosites and jotunites) occur as little as 25 km to the northeast (near Crooked Creek, roughly along strike) in the Number Four 15’ quadrangle (Whitney et al., 2002). These could be potential source rocks that were later separated from the nelsonite during regional Ottawan shearing.
Darling et al. (2018) provide radiometric dates on zircon from the Port Leyden nelsonite. Two zircon textures were observed: 1) highly oscillatory-zoned cores with homogeneous rims, and 2) homogeneous grains. The concordant age on oscillatory zoned cores (n = 14) is 1145.5 ± 4.2 Ma, whereas the concordant age on homogeneous grains and rims (n = 16) is 1036.8 ± 3.8 Ma. Interestingly, the oscillatory zoned cores contain 2-10 micrometer size inclusions of K-feldspar and quartz (Darling, 2016), mineral phases generally not associated with oxide-apatite gabbro norites or jotunites. Therefore, the zircon cores are interpreted as inherited xenocrysts and may suggest mixing of felsic melts with that of the nelsonite parent melt (Darling, 2016). The identification of the included phases was based on EDS analysis so it is plausible that the tiny grains in zircon could actually be kokchetavite and cristobalite, the high temperature, metastable polymorphs of K-feldspar and quartz, respectively, typical of nanogranite melt inclusions (Ferrero et al., 2016). The homogeneous grains and rims are interpreted to have formed during igneous crystallization of the Port Leyden nelsonite. The 1036.8 ± 3.8 Ma age of igneous crystallization is similar to an obtained zircon age (1032.1 ± 3.8 Ma) on the aforementioned stratiform jotunite / anorthosite body, occurring along strike of the regional foliation, 25 km to the northeast, near Crooked Creek (Whitney et al. 2002). The similarity of ages strongly suggests that regionally extensive, folded jotunite / anorthosite layers mapped in the western and central Adirondacks are a likely parental magma source for the Port Leyden nelsonite. The inferred Ottawan age of the Port Leyden nelsonite intrusion has some interesting consequences. First, the nelsonite dike cross-cuts the regional foliation of the metapelite host rocks which suggests the foliation predates the intrusion. If so, when was the nelsonite separated from its inferred parent rocks 25 km to the northeast? Also, if the pyrite banding represents a metamorphic foliation, when was it produced? Is the pyrite banding parallel to the foliation in the country rocks? Only an oriented core of the nelsonite would answer this question. Lastly, the nelsonite does contain metamorphic garnet inferred to have formed by the reaction plagioclase + Fe-oxide → garnet (McLelland and Whitney, 1977). This suggests that garnet-producing metamorphic reactions continued after 1036 Ma.
Darling et al. (2018) report that apatite from the Port Leyden nelsonite, contains 1.1 to 2.1 wt.% total rare earth element oxides, which is about 5 to 10 times more than reported REE contents of apatites from some Norwegian nelsonites (Duchesne, 1999). Chondrite normalized plots of REE abundances in apatite and zircon show: 1) LREE enrichment in apatite, 2) a similar (in magnitude) negative Eu anomaly for apatite and zircon, 3) HREE enrichment in zircon, and 4) a positive Ce anomaly in zircon. No systematic difference was recognized in the REE patterns between the aforementioned zircon types. Furthermore, the REE patterns are typical for igneous zircon (Hoskin and Schaltegger 2003). The negative Eu anomalies of both phases suggest significant plagioclase crystallization in the parent magma. Although the Port Leyden nelsonite contains small amounts of metamorphic garnet, the HREE enrichment in zircon indicates no zircon grew in the presence of garnet.
Small lenses (2 cm width) of nelsonite are locally observed in the surrounding metapelitic gneiss. One such lens occurring in rock excavated from the small hydroelectric plant on the Black River at the end of North St. was found to contain small (1 mm), highly fractured sapphires (Darling et al., 2019). Their rich blue color is attributed to the presence of high amounts (up to 0.22 wt.%) of TiO2, which is not surprising given the composition of the host lens. Although these sapphires are not gem quality, they are the only reported sapphires in New York State, and their presence here demonstrates a previously undescribed geological occurrence in nelsonite.

STOP 3. – Two-pyroxene amphibolite at Lyons Falls
Lyons Falls drops about 63 feet here and has been harnessed as a power source since the mid-1800’s. The base of the falls served as an initial settlement for French explorers of the “Castorland Company,” in June of 1794 (Hough, 1860).
Lyons Falls occurs here because of a ∼100 meter wide band of highly resistant amphibolite gneiss that strikes northeast, normal to the course of the Black River. The amphibolite here is strongly lineated with discontinuous, thin, plagioclase-rich bands. Foliation is poorly developed. D. Valentino (personal communication) describes it as an L-tectonite. The unit has a sharp contact with feldspar-quartz gneiss to the south (observed at the foot of the upstream board dam) but the north contact is not exposed here.
Petrologically, the unit is best described as a medium-grained, two-pyroxene amphibolite. Plagioclase, hornblende, clinopyroxene, and orthopyroxene are the dominant mineral phases. A red-brown (presumably Ti-rich) biotite and opaque magnetite occurs as well (Figure 6). Quartz has been observed but is uncommon. Unlike the central and eastern Adirondacks, the amphibolite at Lyons Falls contains no garnet, despite the fact they are compositionally similar.
The absence of garnet in amphibolites from the western Adirondacks has been known for a long time (Buddington, 1939; de Waard, 1967 and references therein). Its absence is due to lower metamorphic pressures in this region of the Adirondacks as compared to the central and eastern Adirondack Highlands.
Figure 7 shows that the amphibolite of Lyons Falls is located to the west of the garnet + clinopyroxene isograd. In mafic rock compositions, this isograd is based on the reaction:
orthopyroxene + anorthite = clinopyroxene + garnet + quartz (1),
where garnet is present on the higher pressure side of the reaction. The famous garnet amphibolites (e.g. Gore Mtn.), so common in the central and eastern Adirondacks could not form in the western Adirondacks simply because the rocks were not buried deep enough.
The garnet + clinopyroxene isograd across the central Adirondacks has received little attention since first mapped by de Waard (1967). Why the isograd makes two nearly right angle and opposite turns as it sinuates from south to north is unknown. Also unknown is the inferred temperatures and pressures along the isograd and how this compares to other thermobarometric estimates from non-mafic lithologies. The southern terminus of the isograd should have been affected by both the Moose River Plain and the Piseco Lake shear zones (Gates et al., 2004) unless shearing pre-dates garnet formation in mafic lithologies.
Also occurring at Lyons Falls are some meter-scale potholes carved into the amphibolite. These are best observed during low-water levels and closer to the waterfall.

Lunch Stop

STOP 4. – Undeformed pegmatite and hydrothermal sillimanite + quartz veins in Lyon Mtn. granite.
This stop demonstrates important igneous and hydrothermal features of Lyon Mtn. granite along the Moose River. These exposures were first recognized by Buddington and Leonard (1962, p. 93) and studied extensively by McLelland et al. (2001, 2002a, 2002b) and Selleck et al. (2004). Their overall interpretation is that Lyon Mtn. granite experienced contemporaneous intrusion and hydrothermal alteration at about 1035 Ma. The hydrothermal activity leached large cations (K+, Na+) from the granite but left behind Al3+ and Si4+ to form quartz-sillimanite veins. Early vein sets were ductilely deformed (due to magmatic flow or tectonic shear) and younger veins sets formed afterward.
These rocks were included in a large unit of mapped metapelites in Figure 1 of Florence et al. (1995) but the composition and textural features are more consistent with altered igneous rocks. Some of the country rocks into which the Lyon Mtn. granite intruded are indeed metapelites, and numerous exposures of sillimanite + garnet + hercynite + quartz + K-feldspar gneiss occur in the area.
Looking west from the former bridge on the northern side of the Moose River, one can observe an undeformed pegmatite cutting hydrothermally altered Lyon Mtn. granite. The pegmatite is shown in Figure 8 and is compositionally zoned with an uncommon magnetite-rich core. McLelland et al. (2001) dated well-zoned igneous zircons from this pegmatite at 1034 ± 10 Ma. Because the pegmatite is undeformed, the 1034 Ma zircon age has been interpreted as the terminus of Ottawan deformation in this part of Adirondacks (Orrell and McLelland, 1996).
The bedrock exposed farther downstream show excellent examples of quartz + sillimanite veins hosted by Lyon Mtn. granite (see Figure 9). These veins occur in two prominent orientations, N20E and N50E (McLelland et al., 2002a). At other locations in the area (e.g. Ager’s Falls), the quartz-sillimanite veins are nodular in shape and strongly deformed (McLelland et al., 2002a,b). Figure 10 shows the rock texture in thin-section. Note the presence of tartan-twinned microcline; this is in contrast to many nearby metagranites that are characterized by a hypersolvus quartz-mesoperthite mineralogy.
The hydrothermally altered Lyon Mtn. granite here at Lyonsdale is not the only occurrence of this unusual Adirondack rock. Identical sillimanite + quartz vein-hosted granite occurs in a number of locations along strike (to the SW) until ending at Johnson Dam, on the Black River 4.6 kilometers to the southwest.

STOP 5. – Moose River Prismatine locality.
Please exercise caution while walking among the river boulders and talus at the base of the outcrops. Also, please DO NOT USE HAMMERS at this stop and refrain from collecting prismatine specimens unless you’re planning to study them scientifically; a future petrologist or mineralogist will be grateful someday. Moreover, none of the prismatine grains are gem-quality, they are too dark and too fractured!
Prismatine, the boron-rich endmember of the kornerupine solid solution (Grew et al., 1996; ideally Mg3Al6Si4BO21(OH)) occurs in metapelitic and quartzitic rocks along the Moose River. Kornerupine-group minerals are generally rare, having been described from nine localities in the Grenville Province (Grew, 1996; Darling et al., 2004; Korhonen and Stout, 2005) including two in the Adirondacks (Farrar and Babcock, 1993; Farrar, 1995; Darling et al., 2004).
Prismatine is identified here by X-ray diffraction, electron microprobe analyses, SIMS analyses and laser Raman microspectroscopy (Bailey et al., 2019). However, it was first suspected by observing its interfacial angles of about 80 and 100 degrees between the {110} prism faces, values in between those of an amphibole (56° and 124°) and a pyroxene (87° and 93°).
Along the Moose River, prismatine occurs at two locations (separated by about 400 meters, Figure 11) within a unit of heterogeneous metasedimentary rocks (Figure 11, unit BL) mapped by Whitney et al. (2002). This unit comprises mostly quartzite and biotite-quartz-plagioclase gneiss with lesser amounts of calc-silicate rocks, and minor amphibolite, quartzofeldspathic gneiss, and calcite marble (Whitney et al., 2002). These rocks are interlayered with other metasedimentary and meta-igneous rocks (Figure 11). These units occur in a complex, southeast-verging overturned synform bordered on the northwest by a tabular, northwest-dipping body of charnockitic gneiss (CG) several kilometers thick, and on the southeast by a domical body of batholithic proportions consisting of relatively leucocratic CG (Whitney et al, 2002). Although the granitic and charnockitic rocks have not been dated, they are lithologically and geochemically similar to felsic rocks of the ca. 1150 Ma anorthosite-mangerite-charnockite-granite (AMCG) suite found throughout much of the Adirondack Highlands (McLelland et al., 2001; Whitney et al., 2002).
In addition to prismatine-bearing assemblages, the surrounding rocks contain metapelitic assemblages of a) cordierite + spinel + sillimanite + garnet + plagioclase + quartz + ilmenite + rutile ± biotite, b) cordierite + orthopyroxene + biotite + K-feldspar + quartz, and c) orthopyroxene + plagioclase + K-feldspar + quartz ± biotite, ± garnet (Darling et al., 2004).
The feature of geologic interest at STOP 5 are the exceptionally well-developed prismatine crystals in coarse-grained, feldspathic lenses. Here, prismatine crystals form dark greenish-black, euhedral, elongated grains (up to 10 cm in length). Ed Grew (personal communication) indicates that only the prismatine crystals from the Larsemann Hills, Antarctica (Grew and Carson, 2007) are comparable in length to those at Moose River. The prismatine commonly displays radiating patterns in feldspathic lenses one to three cm thick (Figure 12A).
The prismatine crystals appear to have grown only within the plane of the foliation. However, upon closer examination, the prismatine grains are seen to be arranged randomly, but the longest and best-developed crystals formed parallel to the foliation plane. Because of this, Darling et al. (2004) inferred that nondeviatoric pressure conditions prevailed locally during prismatine formation. It should also be noted that a number of prismatine-bearing feldspathic lenses are located adjacent to fine-grained tourmaline + plagioclase + biotite–rich zones near the north end of the exposed rocks. In these locations, the prismatine-bearing feldspathic lenses texturally embay, cross-cut earlier foliation, and appear to form at the expense of the tourmaline-bearing zones (Figure 12B). The embayed country rocks, coarser grain size, and the random arrangement of the prismatine crystals led Darling et al. (2004) to interpret the feldspathic lenses and the prismatine found in them to be of anatectic origin.
Plagioclase, K-feldspar, minor quartz and rutile are the most common phases associated with prismatine, but biotite, cordierite, garnet and rarely sillimanite occur locally as well. The prismatine contains 0.73 to 0.79 formula units of B (out of 1.0) and has Mg / Mg + Fe between 0.70 and 0.73 (Table 3 of Darling et al., 2004). After determining the associated mineral compositions, Darling et al. (2004) proposed the following prismatine-forming reaction:
Tourmaline + sillimanite + biotite + cordierite → prismatine + rutile + melt (2)
Reaction 2 is similar to a number of proposed prismatine-forming reactions from other granulite terranes (Grew, 1996), including those in sapphirine-free rocks found in the Reading Prong, New Jersey (Young, 1995), and in Waldheim, Germany (Grew, 1989). In those cases, garnet rather than cordierite was a proposed reactant. Because prismatine is inferred to form as a direct result of anatectic melting, it is considered a peritectic phase.
Metamorphic temperatures and pressures are difficult to estimate from prismatine-bearing mineral assemblages as little is known about the stability of boron-rich kornerupine at pressures less than 10 kb (Schreyer and Werding, 1997). However, the prismatine occurs in proximity to low-variance metapelitic assemblages in the surrounding rocks. Specifically, thermobarometry calculations from net transfer and exchange equilibria record temperatures and pressures of 850° ± 20°C and 6.6 ± 0.6 kilobars for orthopyroxene + garnet assemblages and 675° ± 50°C and 5.0 ± 0.6 kilobars for cordierite + garnet + sillimanite + quartz assemblages (Darling et al., 2004). The former assemblage is interpreted to have formed during partial melting whereas the latter assemblage is interpreted to have formed on the early retrograde metamorphic path (Darling et al., 2004). The ∼850°C temperatures derived from the orthopyroxene + garnet assemblage are reasonable for partial melting conditions. Although the cordierite + garnet + sillimanite + quartz assemblage occurs at STOP 5, it and the orthopyroxene + garnet assemblage are better developed farther downstream at the second prismatine location (the westernmost open circle in Figure 11). These exposures can be reached by following the footpath on the south bank of the Moose River for a distance of about 400 meters.
Because many of the prismatine-bearing feldspathic lenses are saturated in both quartz and rutile, Storm and Spear (2009) intensely studied the prismatine-bearing lenses as part of a natural test of the titanium-in-quartz geothermometer of Wark and Watson (2006). Storm and Spear (2009) determined a wide range of metamorphic temperatures, specifically from 630 + 63 / -86 to 879 ± 8 °C, but most determinations fell between 700°C and 880°C (see Figure 8a of Storm and Spear, 2009). This is in good agreement with metamorphic temperatures determined by the aforementioned methods (Darling et al., 2004). Storm and Spear (2009) also provide convincing textural evidence that prismatine was locally replaced by leucosomatic quartz, most likely during melting of prismatine. Interestingly, it was the leucosomatic quartz that yielded the highest Ti-in-quartz temperatures (800-880°C; Figure 8a of Storm and Spear, 2009).
The age of partial melting is unknown at this time but is likely associated with either intrusion of the AMCG suite at ∼ 1160-1145 Ma, or burial associated with the Ottawan phase of the Grenville Orogenic cycle and the associated intrusion of Lyon Mtn. granite at ∼ 1050-1030 Ma (McLelland et al., 2010).
Lastly, and perhaps most interestingly, prismatine from the Waldheim granulite, in Germany, was recently found to contain tiny mineral inclusions of coesite, the high pressure polymorph of silica. Moreover, almandine garnet from these same rocks were found to contain the first ever described inclusions of stishovite, the super high pressure polymorph of silica (Thomas et al., 2022)!

A3:THE PISECO LAKE SHEAR ZONE: A SHAWINIGAN CRYPTIC SUTURE IN THE SOUTHERN ADIRONDACK MOUNTAINS, NEW YORK
David W. Valentino
Department of Atmospheric and Geological Sciences
SUNY Oswego,
Oswego, NY 13126
david.valentino@oswego.edu
Jeffrey R. Chiarenzelli
Department of Geology
St. Lawrence University
Canton, NY 13617
jchiaren@stlawu.edu
ABSTRACT
This field trip was first run in 2005 for NYSGA and was reorganized for the 2018 NYSGA-NEIGC joint field conference to show progress in our understanding of the complex geology of the southern Adirondacks. However, in 2018 the trip canceled just prior to the conference due to the sudden tragic loss of Dr. Brian Hough that occurred a few days before the conference. Brian was a colleague of the lead author. Four years later the trip is finally being run again, and it is dedicated to the memory of Brian. Although his tenure at SUNY Oswego was not long, and was tragically cut-short, the impact that he had on many student and colleagues will last a lifetime.
Highly deformed Piseco granitic gneisses occur in an arching east-west transpressional ductile shear zone (Piseco Lake shear zone) that spans the width of the exposed southern Adirondacks. The highly deformed granitic gneisses have restricted silica content, are metaluminous, alkali-calcic to calc-alkalic, continental arc trace element signatures. These granitic rocks intruded supracrustal gneisses resulting in extensive Shawinigan partial melting. The Piseco Lake shear zone (20-30 km wide) formed in this belt of granitic rocks and correlate with a pronounced arcuate-shaped high magnetic anomaly. The magnetic anomaly extends well beyond the exposed Adirondack basement window.
The shear zone is 20-30 km wide and is believed to be the location of a cryptic suture because it occurs between the Adirondack Highlands (underlain primarily by anorthosite and related granitic rocks, AMCG suite) and the Southern Adirondack Terrane (underlain by calc-alkaline tonalitic arc rocks) (Valentino et al., in press). Within the shear zone, the original megacrystic granite contains lineated quartz and rodded feldspar aggregates up to a meter long in places. Along the axis of the shear zone there are thick (1-2 km), subvertical zones of granitic L-S and L-tectonites.
The northern domain of the zone is defined by large foliation domes that are cored by L-tectonite. The southern limbs of the domes steepen toward the south and merge with a wide zone (up to 15 km) of steeply dipping granitic mylonite. Overall, the shear system (domes and steep mylonite zone) forms the core of a region of intense ductile deformation with left-lateral kinematic indicators and subhorizontal E-W ribbon lineations.
The Piseco granitic suite are highly deformed suture-stitching arc plutons that intruded within a sinistral, oblique-convergent, shear system in the deep crust during the Shawinigan orogeny. This is ductile shear zone is the most continuous and largest in the entire Adirondack massif. The shear zone, associated granitic rocks, and the magnetic anomaly abruptly trends toward the south in the eastern Adirondacks. Just beyond this location, the magnetic anomaly appears to be truncated by a branch of the NY-AL magnetic lineament. Following the trace of the magnetic anomaly toward the west, suggests that the shear zone continues for a considerable distance beyond the Adirondack window. It’s magnitude, in addition to the magnitude and extend of the associated magnetic anomaly, suggests that the Piseco shear zone penetrates the Moho.
The current field trip is an update on our very long research project, and it’s geared toward an undergraduate student audience. All field locations were picked to accommodate large student groups. Sampling is generally prohibited by NYS law in the Adirondack Park, and we encourage future instructors to help preserve the field locations presented herein by showing and discussing, and not removing the spectacular bedrock features. Note that the field guide included here in was pirated and modified from the Friends of the Grenville field conference run by D. Valentino, J. Chairenzelli, D. Piaschyk, L. Williams and R. Peterson in 2008.

A3:THE PISECO LAKE SHEAR ZONE: A SHAWINIGAN CRYPTIC SUTURE IN THE SOUTHERN ADIRONDACK MOUNTAINS, NEW YORK

Meeting Point - Charlie Johns Store

STOP 1. Supracrustal rocks of the Adirondack Highlands, just north of the Piseco Lake shear zone
There are several rock types that can be observed at this outcrop, along with the contacts and primary compositional layering. The northern ¼ of the outcrop consists of garnet amphibolite, the next ∼ ¼ of the outcrop is calc-silicate gneiss and the southern ½ is fine-grained quartzo-feldspathic gneiss locally interlayered with highly folded marble (Figure 7). Complex sheath folds with sub-horizontal tight, isoclinal and sheath folds of foliation and compositional layers dominate the rock, particularly in the gneiss (trend to 110o). Excellent views of the folds are seen on top of the southern part of the outcrop. The contacts between the rock types are also folded in similar fashion. Matrix minerals define lineations that are E-W and sub-horizontal, but are variable in orientation due to folding. Overall, the diverse lithologies and style of deformation are typical for the supracrustal rocks located north of the Piseco Lake granitoids. At this point, note that primary compositional layering is preserved at this outcrop.

STOP 2A
The Piseco Lake shear zone includes the northern foliation domes that merge with the steeply dipping shear zones to the south. This series of field stops shows variations in the attitude and type of fabrics that occur in the core of the dome at Piseco Lake. Stops 2A to 2D are a driving traverse around Piseco Lake, the type location of the Piseco antiform. At all of these localities, dynamically recrystallized feldspars and quartz form spectacular ribbon- and rod-shaped mineral lineations (McLelland, 1984), in addition to accessory biotite and magnetite. In many places, the alignment of ribbons forms the foliation in this outcrop. Individual quartz-ribbons have aspect ratios upward of 60:1. At Stop 2A, the foliation is weakly to moderately developed, and dips shallowly southward at the eastern part of the outcrop, but is steeply dipping at the western end of the outcrop. The transition between these different foliation attitudes is difficult to determine because the intensity of the foliation is variable. Lineations are penetrative on all scales, and consistent in attitude (Trend: 110°; Plunge: 05°). Stop 6A occurs on the southern flank of the map-scale dome portion of the Piseco antiform. At the western end of the outcrop there are rods of amphibolite (10-30 cm diameter) within the granitic gneiss.
There is an apparent Mesozoic fault that traces down the western side of Piseco Lake and has locally displaced parts of the Piseco dome (Figure 3). At Stop 2B, again the foliation is weakly developed with a penetrative shallowly plunging lineation. However, the foliation, where it can be observed, dips northerly. As you drive southwest along the western side of Piseco Lake, note that the foliation gradually shallows and then dips southerly. There are several outcrops that can be observed where this transition in foliation attitude occurs. The rock fabrics at Stop 2C are similar to those at Stops 2A and 2B, but again the variably developed foliation dips toward the south. Stop 2D is located at the intersection of Rts. 8 and 10, and the foliation and lineation is penetrative.
Common to all of these field stops is that biotite and sometimes chlorite blades form microscopic lineations and foliation parallel to the macroscopic structure. Rare grains of hypersthene have been found, but they always have well developed overgrowth textures that include biotite and chlorite. The biotite and chlorite are the most abundant index minerals in the granitic gneiss, and suggest the deformation was last active under low- to moderate- metamorphic conditions, although probably began at much higher conditions to account for the relict grains of hypersthene.

STOP 2B:
The Piseco Lake shear zone includes the northern foliation domes that merge with the steeply dipping shear zones to the south. This series of field stops shows variations in the attitude and type of fabrics that occur in the core of the dome at Piseco Lake. Stops 2A to 2D are a driving traverse around Piseco Lake, the type location of the Piseco antiform. At all of these localities, dynamically recrystallized feldspars and quartz form spectacular ribbon- and rod-shaped mineral lineations (McLelland, 1984), in addition to accessory biotite and magnetite. In many places, the alignment of ribbons forms the foliation in this outcrop. Individual quartz-ribbons have aspect ratios upward of 60:1. At Stop 2A, the foliation is weakly to moderately developed, and dips shallowly southward at the eastern part of the outcrop, but is steeply dipping at the western end of the outcrop. The transition between these different foliation attitudes is difficult to determine because the intensity of the foliation is variable. Lineations are penetrative on all scales, and consistent in attitude (Trend: 110°; Plunge: 05°). Stop 6A occurs on the southern flank of the map-scale dome portion of the Piseco antiform. At the western end of the outcrop there are rods of amphibolite (10-30 cm diameter) within the granitic gneiss.
There is an apparent Mesozoic fault that traces down the western side of Piseco Lake and has locally displaced parts of the Piseco dome (Figure 3). At Stop 2B, again the foliation is weakly developed with a penetrative shallowly plunging lineation. However, the foliation, where it can be observed, dips northerly. As you drive southwest along the western side of Piseco Lake, note that the foliation gradually shallows and then dips southerly. There are several outcrops that can be observed where this transition in foliation attitude occurs. The rock fabrics at Stop 2C are similar to those at Stops 2A and 2B, but again the variably developed foliation dips toward the south. Stop 2D is located at the intersection of Rts. 8 and 10, and the foliation and lineation is penetrative.
Common to all of these field stops is that biotite and sometimes chlorite blades form microscopic lineations and foliation parallel to the macroscopic structure. Rare grains of hypersthene have been found, but they always have well developed overgrowth textures that include biotite and chlorite. The biotite and chlorite are the most abundant index minerals in the granitic gneiss, and suggest the deformation was last active under low- to moderate- metamorphic conditions, although probably began at much higher conditions to account for the relict grains of hypersthene.

STOP 2C
The Piseco Lake shear zone includes the northern foliation domes that merge with the steeply dipping shear zones to the south. This series of field stops shows variations in the attitude and type of fabrics that occur in the core of the dome at Piseco Lake. Stops 2A to 2D are a driving traverse around Piseco Lake, the type location of the Piseco antiform. At all of these localities, dynamically recrystallized feldspars and quartz form spectacular ribbon- and rod-shaped mineral lineations (McLelland, 1984), in addition to accessory biotite and magnetite. In many places, the alignment of ribbons forms the foliation in this outcrop. Individual quartz-ribbons have aspect ratios upward of 60:1. At Stop 2A, the foliation is weakly to moderately developed, and dips shallowly southward at the eastern part of the outcrop, but is steeply dipping at the western end of the outcrop. The transition between these different foliation attitudes is difficult to determine because the intensity of the foliation is variable. Lineations are penetrative on all scales, and consistent in attitude (Trend: 110°; Plunge: 05°). Stop 6A occurs on the southern flank of the map-scale dome portion of the Piseco antiform. At the western end of the outcrop there are rods of amphibolite (10-30 cm diameter) within the granitic gneiss.
There is an apparent Mesozoic fault that traces down the western side of Piseco Lake and has locally displaced parts of the Piseco dome (Figure 3). At Stop 2B, again the foliation is weakly developed with a penetrative shallowly plunging lineation. However, the foliation, where it can be observed, dips northerly. As you drive southwest along the western side of Piseco Lake, note that the foliation gradually shallows and then dips southerly. There are several outcrops that can be observed where this transition in foliation attitude occurs. The rock fabrics at Stop 2C are similar to those at Stops 2A and 2B, but again the variably developed foliation dips toward the south. Stop 2D is located at the intersection of Rts. 8 and 10, and the foliation and lineation is penetrative.
Common to all of these field stops is that biotite and sometimes chlorite blades form microscopic lineations and foliation parallel to the macroscopic structure. Rare grains of hypersthene have been found, but they always have well developed overgrowth textures that include biotite and chlorite. The biotite and chlorite are the most abundant index minerals in the granitic gneiss, and suggest the deformation was last active under low- to moderate- metamorphic conditions, although probably began at much higher conditions to account for the relict grains of hypersthene.

STOP 2D

STOP 3. Steeply dipping mylonite zone of the southern PLsz
Along Powley Road, depending on the time of year and the amount of road maintenance, there are a sub-continuous series of pavement exposures located in the road bed, as well as in the gutter on the east (northeast-bound) side of the road. Due to the nature of this location, the extent of the exposed rock at this stop changes yearly, so some or all of the rock described here may be viewable depending upon the time of the season in which the stop is visited (best later in the summer). The best exposures occur along the road between West and East Notch Mountains.
All rocks in this region are very similar in mineral content, and vary only in detail with regard to mineral percentage and fabric type and intensity. The rock is dominantly granitic gneiss with intense subhorizontal to shallowly plunging mineral elongation lineation that trends on average about 095 o, with steeply dipping generally east-west striking foliation. Both fabric elements are defined by ribbons of quartz, and ribbons of aggregate feldspar and quartz (generally 1-5 cm long depending upon grain size). Intensity of the fabric varies across strike at the 50 cm scale, with local layers of significantly coarser-grained fabrics (grains up to 1 cm in diameter). There are also places where the foliation intensity varies as seen at the field stops around Piseco Lake. Rare amphibolite bodies that are 10’s of cm thick occur within the granitic gneiss. Shear sense indicators are abundant in the granitic rocks and consistently show sinistral shear sense.

STOP 4. Southern extent of steeply dipping mylonite
Here the granitic gneiss fabrics contain both a penetrative foliation and lineation. The foliation is steeply dipping and strikes about east-west. Mineral elongation lineation defined by linear aggregates of quartz and feldspar are subhorizontal. The extent of readily available bedrock exposure diminishes south of this location, so this may be the southern-most exposure of the Piseco Lake shear zone. Note that this location is about 21 kilometers across strike from the northern side of the Piseco dome where the pronounced lineation occurs.

Parking for Stop 5

STOP 5: L>>S and L-tectonite in the core of the Piseco antiform
Excellent outcrops on the northwestern side of a small hill just west of the parking area. Follow the dirt road to a path through the woods, and then head up hill to the south to the outcrops. This outcrop of granitic gneiss contains domains of LS and LS. The LS domains contain large and numerous σ-type shear sense indicators, some δ-type are present but are much less frequent. The porphyroclasts are large about 1-3 cm and the recrystallized porphyroclastic material is often wrapped with a quartz ribbons. The interpreted shear sense is low-angle and left lateral. The foliation strikes east-west and dips gently to the south. Return to the vehicles by following the path. At this point the trip is over. Retrace your trip to Route 8. If you are headed back to Lake George, then follow Route 8 back to Speculator, NY, then turn south on Route 30.

A4 Outdoor Earth Science - a Geological-Ecological Nature Trail For Students Of All Ages
N.J.Difrancesco
Geology Department
University at Buffalo
Buffalo, NY, 14206
ABSTRACT
The field of geosciences addresses a wide range of Earth processes and materials. Individuals of all ages tend to learn about these topics in much the same way, regardless of their grade or level of education. These concepts are best understood when learners can physically see and interact with these processes and materials in their natural environments. We have taken this approach to develop an immersive, geoscience-themed learning experience for visitors to Rice Creek Field Station (RCFS) in Oswego, NY. Participants will hike an approximately 2-mile long ‘geology trail’ that explores various sites of geological interest, giving them an opportunity to see and interact with the environment both literally and virtually. At each stop, participants will be able to see and feel the varied textures of different types of rock, walk the change in topography left behind by glaciers, watch the movement and flow of water eroding sediment, and see how the land has been shaped by natural and human processes over thousands of years. Maps and placards at each stop will provide information and help guide participants navigate the trail; scannable QR codes linked to websites support a more in-depth understanding of fundamental concepts, and student research taking place at each location. This supports a more complete learning experience and provides greater context of the science for learners of all levels.
RCFS is used primarily by students and faculty of Oswego State University, however, many other local groups and residents regularly make use of the trails and facilities. This presents a valuable opportunity to engage with the public and provide science outreach for adults and students in the area. This project has been developed and maintained by undergraduates who are able to use this as a forum to preserve and communicate their research on local geology to individuals who frequent the park, while educating them about fundamental scientific principles. It also provides K-20 Earth science teachers a destination to share outdoor field experiences with their classes, while reinforcing objectives of state and national science curricula. We provide a simple model for integrating science outreach and education in an outdoor setting that can be easily adapted to many different local settings.
INTRODUCTION
Rice Creek Field Station (RCFS) is a public space dedicated to research and education in the natural sciences to individuals of all ages, which is of particular interest and use to individuals in the Oswego area. Many examples of geological materials and processes that define Central New York are on display at Rice Creek, we will explore some of these during the walk around the property. Glacial and fluvial deposits dominate the surface materials in Central New York (fig. 1). Glacial till is the major surface material, in addition to kame and glacial sands. Lacustrine sands and clays are also minor components of the surface in the area due to the formation of proglacial lakes and streams. In addition to the abundant materials indicating the influence of glacial activity, there is also striking geomorphological evidence of glacial advance preserved in the topography of the region (fig. 2). Small hills, or drumlins dot the landscape south of Lake Ontario across a large swath of Central New York. RCFS encompasses one of these drumlins, allowing park goers to observe the scale of sediment deposits formed by the movement of ice during the last glacial maximum. RCFS has an extensive trail system that traverses the entire park (fig. 3), allowing visitors to explore various types of geologic materials (rocks, sediment, water) and features (hills, streams, water bodies) formed by natural and human interactions.
While observing these features at RCFS is an effective and educational experience- this area is far from unique, and these features and materials are not quite “world class”, however they still provide an ideal environment for learning about basic geologic concepts that often can befuddle students from junior high school through a freshman year in college. Often, there is a great deal of overlap between the content of course work for students aged from 10 to 21, making immersive experiences like this beneficial to a large swath of the population. Further, non-students that are part of the general population who frequent locations such as RCFS can also benefit from outreach programs that employ this hands-on, outdoor, educational approach. It is the goal of this field trip to not simply educate, but encourage educators to develop similar experiences for students of all ages in areas (parks, preserves, campuses) convenient and relevant to your population.

Blue trail

Orange trail

Red trail

STOP 1: Bottom of the drumlin
Proceeding north along the red trail, away from the pavilion the group will walk approximately a quarter mile until reaching the intersection with the orange trail. At this point, we will bear to the right and walk up the orange trail. Here, we can notice the trail steepen- this is the edge of the drumlin. When you look up the trail you can see that you are looking up the slope of it (Figure 4).

STOP 2: Meta/igneous erratic
Here just off the trail, there is an erratic made of granite. We will take the opportunity to discuss the fact that an erratic is a rock or boulder that differs from the surrounding rock and is believed to have been brought from a distance by glacial action. We will discuss the differences between the sedimentary rock that makes up the bedrock of most of Central NY (fig. 5), and contrast that with the magma that formed this rock. It is notable that this is different from the regular glacial sediment, as these erratics are by definition quite large and stick out, as this one does. In addition, we can discuss the composition- the minerals in it are, potassium feldspar (pink), quartz (white/clear), and biotite mica and hornblende (black).

STOP 3: Granitic erratic
This erratic is a granite, which is an igneous rock. The minerals in it are potassium feldspar (pink), quartz (white/clear), and biotite mica (black). Note the difference in color and texture from the previous stop. It is clear that these erratics are from different sources, in addition to being distinct from the sedimentary rock forming the bedrock in this area.

STOP 4: Large intermediate meta-igneous erratic
Here we have another erratic. This one is significantly bigger than the other two and is what's known as a diorite gneiss. The sodium plagioclase (white), and hornblende and biotite (black). The minerals in this rock are substantially darker than the other granitic rocks we’ve observed. This demonstrates the variability in composition of many of the erratics that are deposited in RCFS. We can also note the variable texture of this rock (pegmatite veins), suggesting interaction with fluids (Figure 6).

STOP 5: Top of the drumlin
This stop is the top of the drumlin. At this point this surface was directly in contact with the glacier. At that point you would be standing under nearly 2 miles of ice. After the glacier ablated, the melt water flooded the area, creating glacial Lake Iroquois. This lake eroded and flattened the tops of many of the drumlins closest to Lake Ontario today.

STOP 6: Seasonal stream
Walking down the side of the drumlin, we see evidence of groundwater infiltration as well as surface runoff. Seasonal streams such as these running along and beside the trail help to gradually erode and wear down the surface. This is a visual representation of a large scale process operating at a very small scale. Also observable is particle sorting- small particles of clay are carried further than larger particles of silt, and sand. The effect is more dramatic directly after heavy rainfall, but it is useful to illustrate these processes.

STOP 7: Bog
A bog is a type of wetland that is too soft to support a heavy body. Walking off the trial, you will sink a little bit. A bog is also known for the accumulation of peat. Peat is a deposit of dead plant material, and another major constituent of the local surface geology (fig. 2 – peat and muck). It can be discussed that this peat gets buried and lithified (compressed into a rock) it forms coal.

STOP 8: Rock Wall
Proceeding down the orange trail to the intersection with the blue trail, we come across one of many rock walls that are constructed throughout RCFS (fig. 7). Notice, the majority of the rock forming the wall is flat, squared off sandstone/siltstone- this is the Oswego formation, and makes up the majority of rock in the area.
In contrast, there are occasional rounded stones that are made of granite, gneiss, or some other igneous/metamorphic rock. These rocks are very different from the sandstone, and they each have very different formational histories.

STOP 9: Bridge over stream and vernal pool
This section of the blue trail is damp, requiring a bridge likely because the surface is quite close to the water table. This area is also home to a vernal pool (or ephemeral pool) that forms during the rainy season. These are temporary bodies of surface water that provide sanctuary to different species of plants, insects, and animals. It should be understood that these pools form as a consequence of the local geology and environmental conditions which can vary throughout the year.

STOP 10: Meandering stream
Another stream draining off the drumlin, and flowing along the flat lowland along the base of the hill. This stream clearly shows a meander- it is a single channel, but we can observe that it winds back and forth, following the route of least resistance (fig. 8). Closer examination of the stream channel, we can see sorting of sediment, grading from coarser to finer moving closer to the shoreline. Point bars can be identified as well, forming as a consequence of the stream flow.

STOP 11: Rice Creek
Here we follow the blue trail down to the deep, wide channel of Rice Creek for which the field station is named. Walking upstream, we see the flowing water has eroded much of the loose, finer, sediment from its channel, exposing more of the cobble to boulder-sized till. These rocks are continually being mechanically and physically weathered by the movement of the creek. This water flowing out of Rice Creek will eventually enter into Lake Ontario as a minor tributary. Walking along the creek, it may be possible to visit the artificial dam that forms Rice Pond.

STOP 12: Rice Pond
Rice Pond is artificially formed by the dam at the northern edge of the pond. Rice Pond conforms to the local topography and geology of the area as Rice Creek has flooded the lowest points of the valley. Proceeding further south, the pond transitions into another large swamp/bog. Note that the flow has slowed considerably, but not stopped. This allows for deposition of sediment that has been transported from further upstream. Walking along the shoreline of the pond will lead back to the traffic circle and the start of the walk.

B1 Detrital Zircon Geochronology of the Adirondack Lowlands
JEFF CHIARENZELLI
Department of Geology
St. Lawrence University
Canton, NY 13676
WILLIAM DELORRAINE
1 Indian Head Trail
Gouverneur
NY 13642
MARIAN LUPULESCU
New York State Museum
3140 CEC Madison Ave.
Albany, NY 12230
ERKAN TORAMAN
Department of Geological Sciences
Salem State University
352 Lafayette Street
Salem, MA 01970
ABSTRACT
During this day-long trip we will visit and discuss several sites in the Adirondack Lowlands for which detrital zircon geochronology is available. Stops will include quartz-rich protoliths from throughout the upper Amphibolite facies stratigraphic succession including the turbiditic sequence at Pyrites, NY, sandy and tourmaline-rich intervals in the Lower marble, sandy, calc-silicate interlayers within the Popple Hill gneiss, and base, middle, and top of the Upper Marble. The data collected to date has important implications for the age of metasedimentary rocks deposited before Grenville orogenesis, shifting provenance in response to tectonism, the events leading to the formation of the world-class Pb-Zn sedimentary exhalative deposits, the timing and intensity of metamorphism in the Lowlands, and potential basement rocks. Much of this information is summarized from Chiarenzelli et al. (2015a; 2017); some is a summary of on-going work.

Meeting Point

STOP 1 Lower Marble, Richville, Tourmaline-bearing gneisses
The Lower Marble includes a number of detrital metasedimentary rocks in addition to the marble and subordinate calc-silicate gneiss (Wiener et al., 1984). Of particular interest is an extensive (50 km) belt of black to reddish-brown tourmaline-rich rocks that are interlayered with dolomitic marble near the top of the sequence (Brown and Ayuso, 1985; deLorraine and Carl, 1986). Along Rt. 11, just outside of Richville, a meter-thick layer of feldspathic quartzite (arkose) within biotite, tourmaline and pyriterich gneiss was sampled for U-Pb zircon geochronology.
A meter-wide, shallowly inclined quartz-rich layer, whitish in color, on the north side of Rt. 11 was sampled (Figure 14). A small population (n = 300-400) of zircon grains and a large number of pyrite and tourmaline grains were separated from approximately 1 kg of sample. The zircons ranged in size from 50 to 300 µm and were predominantly rounded to oval in shape, although some are euhedral (Figure 15). Truncated oscillatory zoning and a few, thin 1-5 µm, partial, euhedral metamorphic overgrowths were observed. Uranium concentrations in zircon range from 12 to 742 ppm and average 163 ± 135 ppm. Ratios of uranium to thorium range from 0.4 to 12.4 and average 2.0 ± 1.9. The vast majority of analyses are concordant.
One hundred and one grains are near concordant and show a wide range of ages from 1241.6 Ma to 3082.9 Ma. The youngest grain analyzed is 1241.6 ± 41.9 Ma. A cohort of the 20 youngest grains, all within analytical error of one another, gave a weighted mean of 1263.9 ± 4.3 Ma (MSWD = 1.4; PROB= 0.11), and are interpreted as the age of the youngest detrital population. Two large peaks, one at 1260.2 ± 4.7 Ma and the other at 1841 ± 2.1 Ma, are clearly defined on the probability density histogram (Figure 16) and represent the dominant ages found in this sample.

Stop 2 Upper Marble, Unit 4, Balmat, Stromatolites
This classic outcrop contains putative stromatolites originally noted by Yngvar Isachsen (Isachsen and Landing, 1983). Located directly across from the Titan Corporation Mine, here the contact between Units 4 and 5 of the Upper Marble can be seen. Structurally we are located on the overturned limb of Sylvia Lake Synform, which is consistent with the downward concave shape of the stromatolites.
The outcrop directly across from the entrance to the former Zinc Corporation of America headquarters near Sylvia Lake was sampled for detrital zircon geochronology (Figure 18). The rock sampled is from Unit 4 and comprised mostly of dolomite and diopside. It exhibits silicified layering interpreted as remnant stromatolites (Isachsen and Landing, 1983). Here the matrix between the sparse, upside-down stromatolite domes (located on the overturned limb of the Sylvia Lake Synform) was sampled and consisted of quartz, dolomite, serpentine, titanite, and gray diopside (no stromatolites were harmed or disfigured during the procurement of this sample). A sparse yield of approximately 200 silt-sized (20-100 µm) zircons of rounded to angular shape was obtained (Figure 19).
The U-content of zircons ranges from 95 to 2331 ppm and averages 947 ± 431 ppm, considerably higher than all other samples. Ratios of U /Th range from 1 to 113 and averages 12 ± 18. Because of the small size of the zircon and high U-content, little in the way of internal features can be discerned as the BSE signal is very homogeneous (Figure 19). Every grain in the mount larger than the 30 µm analytical spot size was analyzed, yielding 92 data points. Nearly all grains are within± 3% of Concordia.
The youngest zircon grain analyzed gave an age of 994.7 ± 29.1 Ma, which falls within the time frame noted for the Rigolet pulse of the Grenvillian Orogeny. A cohort of 66 grains yielded an age of 1172.7 ± 3.0 Ma (MSWD = 1.09; PROB = 0.30). Thirteen grains yield ages ranging from 1214.5 to 2607.5 Ma (Figure 20). Two grains gave a weighted mean of 1224 ± 13 Ma (MSWD = 0.34; PROB = 0.80), interpreted as the timing of Elzevirian metamorphism or analysis ablation pits that sample across age domain boundaries.

STOP 3 Upper Marble, Unit 16, Talcville, Median Gneiss
The Median Gneiss (Unit 16 of the Upper Marble) is the youngest member of the stratigraphic succession of the Grenville Supergroup in the Lowlands. It is primarily a pink, strongly layered, quartzofeldspathic rock with a small percentage of other minerals such as diopside, micas, tourmaline, hornblende, and scapolite. Foliation-parallel layers of leucosome and feldspar porphyroclasts attest to the unit’s metamorphic grade and deformation (Figure 22). The protolith of the Median Gneiss is not known, although its composition is granitic or arkosic. A 1 kg-sized sample was collected from a small outcrop exposed near Talcville, New York and it yielded thousands of zircon grains.
The zircon grains range in size from 30 to 100 µm in diameter; most grains are about 50 µm and rounded, but small populations of angular and elongate grains were also noted (Figure 23). The average U-content is 842 ± 548 ppm and ranges from 52 to 2892 ppm. Ratios of U /Th range from 0.63 to 27.78 and average 3.28 ± 3.23.
Zircon U-Pb analyses yielded ages from 1185.4 to 3303.3 Ma. Over 300 grains were analyzed; however, those falling outside the range of 95-105% concordant were filtered out of the data set leaving 158 analyses to be plotted (Figure 24). Of these, the largest peak on the probability density histogram is 1524.8 Ma. Two grains yield an age of 1234 ± 12 (MSWD = 0.29; PROB = 0.59), falling within the range of timing of Elzevirian orogenesis. The next five oldest grains form a coherent group with an age of 1253 ± 17 (MSWD = 3.7; PROB= 0.005).

STOP 4 Pyrites Complex, Pyrites, Turbiditic Basal Unit,
Along the Grasse River near the adits to the old pyrite mine at Pyrites, New York, small samples of quartz-rich (~ 85% SiO2), cm-scale interlayers within a gamet-sillimanite pelitic gneiss were removed utilizing a chisel and processed for zircon. The rock shows isoclinal folding of interbedded quartzite and metapelitic layers (Figure 26). Centimeter-scale layers are interpreted as the alternation of sand, silt, and mud formed within a turbidite sequence (Chiarenzelli et al., 2015). Three meters structurally below the sample site, a coarsegrained, green, hydrothermally altered peridotite is exposed. These rocks, along with more extensive gabbroic and amphibolitic units, have been named the Pyrites Complex and interpreted as a highly disrupted ophiolite suite (Chiarenzelli et al., 2011a). Continuous exposure, gradation in the composition of the metasedimentary rocks, and the occurrence of chromite (Tiedt and Kelson, 2008) in the pelitic gneiss near the contact suggests the metasedimentary sequence overlies the ultramafic in apparent depositional contact.
A small separate (n = several hundred grains) of zircon was obtained from a kilogram of sample quartzose, sand to silt-sized portions of the aforementioned outcrop. Zircons recovered are relatively small (<100 µm), oscillatory zoned, and have shapes ranging from stubby dipyramids to grains with slightly rounded boundaries (Figure 27), thought modified by erosion. The zircons from this sample are noteworthy for their homogeneity. The U-content of the zircons analyzed in this sample averaged 243 ± 93 ppm and their U /Th ratio is 1.6 ± 0.4. Most grains are concordant with a range of 104.0-94.7%.
Ninety-seven near-concordant grains are plotted (Figure 28) and a group of 86 yielded a weighted average of 1289.7 ± 1.1 Ma. One grain, of smaller size and lacking visible zoning, gave an age of 1176.2 ± 24.1 Ma, in excellent agreement with the timing of Shawinigan orogenesis, and is considered to be metamorphic. Another grain yields an age of 1237.5 ± 24.1 Ma, the timing of Elzevirian orogenesis in the Grenville Province and is also interpreted to be of metamorphic origin. A group of five analyses that are statistically indistinguishable, gave a weighted mean age of 1258.3 ± 7.7 Ma (Mean Square Weighted Distribution (MSWD) = 1.4; Probability (PROB) = 0.22) and are interpreted to be the age of the youngest detrital population. Six other detrital grains range in age between 1372.9 ± 21.2 Ma and 2294.9 ± 21.7 Ma.

STOP 5 Brown Hall on SLU campus
A section of drill core from an overturned limb of the Sylvia Lake Syncline near Balmat, New York (Figure 30) penetrated the upper portion of the Popple Hill Gneiss and the lower portions of the Upper Marble (Chiarenzelli et al., 2012). The transition is considered to be conformable as the percentage of quartz in Popple Hill Gneiss gradually increases upward into ~ 30 m of glassy quartzite (Figure 31), then transitions into schist, before the first marble interval is penetrated. Portions of split drill core from several meters of section composed of the glassy quartzite were sampled, crushed, and zircon grains separated.
An excellent yield of several thousand grains was obtained from 1 kg of sample. Grains range from highly rounded to angular (Figure 32). Their average size is about 100 μm, with large rounded grains up to 300 μm. Smaller angular and euhedral grains are also present. Many zircon grains show truncation of oscillatory zoning, but distinct overgrowths are few, thin, and incomplete. The average uranium content of zircons from the sample was 106 ± 75 ppm and U /Th range from 0.4 to 13.6 and average 1.5 ± 1.5.
One hundred and seven near-concordant grains were plotted and showed a wide range of ages from 1270.8 Ma to 3388.3 Ma. The youngest grain analyzed gave an age of 1270.8 ± 113 Ma (note the large error). A cohort of 5 youngest grains, all within analytical error of one another, gave a weighted mean of 1277.9 ± 13 Ma (MSWD = 0.09; PROB = 0.994) and are interpreted as the age of the youngest detrital population. Two large populations, one at 1446 ± 7.8 Ma and 1650.3 ± 6.2 Ma, occur on the probability density histogram (Figure 33).

Stop 7 – Canton Alaskite Body, Canton, Leucogranite and amphibolite
About a dozen, kilometer-scale, domical leucogranite bodies, known as alaskites occur throughout the Adirondack Lowlands. Originally interpreted as volcanic rocks at the base of the stratigraphic sequence (Carl and van Diver, 1975; Carl et al., 1990; deLorraine and Carl, 1986), subsequent work (McLelland et al. 1992; Peck et al., 2013; Wasteneys et al., 1999) has reinterpreted the suite as of intrusive origin. Known as the Hyde School gneiss these bodies range in composition, contain supracrustal xenolithic screens, and are often intruded by dismembered mafic dikes/sills or layers (now amphibolite). A large portion of these bodies consist of medium-grained interlocking crystals of alkali feldspar, plagioclase, and quartz. Nearly all mafic minerals are magnetite. Foliation is often difficult to see, however, the rock is gneissic in nature particularly near the margins of the bodies. A kilogram sized sample was collected from the pink leucogranite layer above the mafic enclaves in Figure 35.
Zircons from the leucogranite bodies investigated thus far are dominated by large crystals yielding core ages of ca. 1325 Ma. Some show dissolution, presumably from interaction with magma, during the formation of their igneous precursors. Many zircons have thin, clear, rims which yields an U-Pb age of ca. 1170 Ma. A small population of euhedral, smaller crystals lacking cores, are often observed. Earlier attempts (1985) to date the zircons using multi-grain samples yielded hybrid ages (ca. 1230 Ma; McLelland et al., 1992). Subsequent attempts at dating using refined techniques (single grain analyses of coreless crystals) yielded an age of 1172 Ma (Wasteneys et al., 1999). This data indicates substantial inheritance from the source terrane(s).

STOP Bonus Popple Hill Gneiss, Pierrepont, Calc-silicate interlayer
This stop was located using the photograph, not the coordinates of Figure 38. Those coordinates, 44.500852, -75.083131, would move this Placemark 335 ft to the NNW. Google Earth clearly shows rock at the location in the photo, so that is why it has been used.
A stop on private property at O’Brien Rd. in Canton, New York will be made if time and interest permits.
A rusty, granular, calc-silicate gneiss was sampled from a 10 cm thick interval in garnetbearing pelitic portion of the Popple Hill Gneiss near O’Brien Road, near West Pierrepont, New York (Figure 39). The gneiss is interlayered and cut by numerous concordant to discordant leucogranitic gneissic sheets. The Popple Hill Gneiss consists of a thick (several kilometers?) sequence of metamorphosed mud, silt, and sand, that is, at least in part, turbiditic (Chiarenzelli et al., 2012). Samples from partially melted pelitic to psammitic portions of similar gneisses have been investigated for U-Pb zircon geochronology by Heumann et al. (2006) and Bickford et al. (2008) in the Adirondack Lowlands and Highlands and have been shown to have zircons of both detrital and igneous-anatectic origin.
A small population (~500 grains) of zircons was separated from a kilogram-sized sample of rusty calc-silicate gneiss (Figure 40). Zircons range in size from 20 to 80 μm and display a wide range of shapes from nearly rounded and oval to subhedral and faceted. A number of angular grains also occur.
Seventy-nine grains are near concordant and yielded a range of ages between 1127.0 Ma and 1667.4 Ma (Figure 41). A population of 61 grains yielded an age of 1170.6 ± 4.0 Ma (MSWD = 1.5; PROB = 0.010), which falls in between the range of 1180-1160 Ma interpreted by Heumann et al. (2006) as the time of anataxis in nearby samples of this unit. Two grains, interpreted as the youngest detrital population, give an average age of 1260 ± 23 Ma (MWSD = 0.024; PROB = 0.88). Four grains gave an age of 1223 ± 8 Ma and are interpreted as metamorphic (Elzevirian) or hybrid in origin (MSWD = 0.57; PROB = 0.64).

B2 Eastern Lake Ontario Dune-Wetland Complex From the Pleistocene to Today - Laurentide Ice Sheet Deglaciation, Shoreline Evolution And Moden Geoecology
Roy L. Widrig
New York Sea Grant
State University of New York at Oswego
Oswego, NY 13126
INTRODUCTION
The Eastern Lake Ontario Dune Complex and associated landforms, coastal morphology and wetlands have survived through constant change since the Late Pleistocene. While the general location of the Lake Ontario shoreline is the result of deglaciation of the Laurentide Ice Sheet (16,000-12,000 YBP) and drainage of Glacial Lake Iroquois, the natural processes acting upon the 27 km stretch of dunes is modified further by complexities of human interaction with the landscape since European settlement post-colonization. Today, natural processes such as longshore transport of sediment, climatic influence on lake level, erosion at the headwaters of Lake Ontario tributaries, and human intervention such as lake level controls and shoreline erosion management are in discordance with one another. The natural climatic and geologic processes in the context of human settlement along the lake creates a balancing act in which human settlements attempt to remain resilient while conserving and protecting delicate coastal ecosystems.

STOP 1 Meeting Location: Black Pond Wildlife Management Area
Discussion Eastern Lake Ontario Dune Complex – Dune Formation and Modern Habitats

STOP 2 Deer Creek Marsh Wildlife Management Area - North
Discussion Sand dune and wetland management, dune system hydrology.

STOP 3 Sandy Island Beach State Park – Main Parking Lot
Discussion: Human Intervention and Conservation in Dune Systems

STOP 4 Salmon River Bridge – DEC Launch Parking Lot
NOTE: There is only space for nine vehicles here and NY-3 is very busy. This stop is optional.
Discussion: Dunes, recreation, politics and conservation.

B3 Middle Ordovician Clastics, Fractures, Faults And Water Fall - Geology Of the Salmon River Gorge, Almar, NY
David W. Valentino
Department of Atmospheric and Geological Sciences
State University of New York at Oswego
Joshua D. Valentino
Terracon
19955 Highland Vista Drive Suite 170
Ashburn, VA 20147
Richard W. Inclima
517 County Route 4
Central Square, NY 13036
INTRODUCTION TO THE REGIONAL GEOLOGY
The Tug Hill plateau is underlain by the Lorraine Group, that consists of a number of siliciclastic rock formations from oldest to youngest, the Utica, Whetstone Gulf, Pulaski and Oswego. The Utica shale and Oswego sandstone are end-members in a stratigraphic sequence that has increasing amount of siltstone and then sandstone beds upward progressively. This sequence of rocks represent the middle Ordovician trough that filled with clastic sediments in response to the Taconian orogeny, the Taconic Clastic Wedge. The high region of Tug Hill plateau is drained by rivers and streams that flow radially from the plateau in all directions, and most of these drainages have carved deep gulfs and gorges exposing the carbonates of the Trenton Group and the Lorraine Group clastics. The Salmon River flows from the plateau interior into the Redfield Reservoir. Downstream of the reservoir, the river flows over the top of the Oswego sandstone to the Salomon River falls (Figure 1). At the falls, the river plunges 33 meters into the top of the Pulaski Formation (interbedded sandstone, siltstone and shale), and forms the Salmon River gorge downstream. The river is bound by the gorge within the geographic limits of the Oswego formation. Exiting the Oswego formation, the Salmon River flows through a generally shallow banked cut in the Pulaski Formation, until it reaches Lake Ontario at the town of Port Ontario. This field trip is a visit to the Salomon River falls to examine the transition in strata near the top of the Taconic Clastic Wedge, structures in the strata, and how these features of the bedrock have contributed to the formation of the Salmon River falls and controlled the flow direction of the river. This trip includes two locations: 1. Top of the falls; 2. Below the falls (Figure 1).

STOP 1 Salmon River Falls
Park vehicle in the designated place. Follow the path northeast to the top of the Salmon River Falls.
This stop description was first prepared for the 2005 NYSGA conference and appears in Stilwell et al. (2005). Follow the steep path (with stone stairs) into the Salmon River gorge. The path splits in two directions at the river level. Follow the river bank to the right (southwest) about 200 m to the waterfall. Stop 5 is the series of outcrops that start at the waterfall and end at the sharp bend in the river downstream. At the river level, thick beds of sandstone comprise the lower part of the Pulaski Formation. Long joints (up to 30 m long), strike about 025 and are steeply dipping. These fractures are spaced about 1-2 meters and intersect discontinuous joints that strike northwest (Figure 9). The thick sandstone beds are overlain by interbedded sandstone, siltstone and shale that is progressively more dominated by fine grained sedimentary rocks upward. This sequence of rocks is best viewed in the cliff face that occurs in the sharp bend in the Salmon River. Walk back to the path and climb up the gorge. Follow the path eastward to the top of the Salmon River Falls. At this location, please obey all safety signs and stay in the designated areas. Stop 6 is the pavement outcrop at the top of the falls of Oswego Formation. Here the rocks are green-gray sandstone with abundant ripples and large cross-beds. Joints transect the entire outcrop for many meters and occur in complex zones. The dominant joint set strikes about 060, but is associated with some complex joint patterns. In places the individual joints with an average strike of 035 curve and are continuous with the 055 striking fractures. Additionally, there are en echelon fracture zones with apparent left lateral geometry that merge with the dominant fracture set, and large right-stepping fracture zone (Figure 7)