IDEAS Field Trip - Geology of Southeastern New York
October 28-29, 2006

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JBT_torrent.JPG
Torrent at John Boyd Thatcher State Park coming from underground stream discharging along the escarpment.
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Outlet Falls along the Indian Ladder Trail.
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Outlets Falls flowing as a torrent, rather than a trickle due to the heavy rainfall earlier in the day.
underground_stream_sign.JPG
Explanation of the geology at JBT.
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Outlet Falls gushing from a notch in the escarpment.
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Closeup of Outlet Falls.
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Base of Outlet Falls
Albany_plain.JPG
View NE across the Albany plain from the escarpment.
Coeymans_fossils.JPG
Crinoid and coral fossils exposed on the surface of a bed of the Coeymans Limestone, roadcut at Thruway exit 21, near Leeds, NY.
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Room and pillar cement mine in Rosendale Dolostone, Williams Lake Hotel.
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Cement mine room. Note the 45 degree dip of the strata. The ceiling of the mine is the Glasco Limestone, which was not mined because it does not produce natural cement.
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A colony of the Silurian tabulate coral Cystihalysites weathering out of the base of the Glasco Limestone.
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Closeup of Cystihalysites colony showing chainlike morphology of interconnected coralites.
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Cateniform (chainlike) colony of the Silurian tabulate coral Cystihalysites.
WL_cement_mine2.JPG
Large pillars of Rosendale Dolostone were left behind in the mine to support the ceiling during mining.
WL_cement_mine3.JPG
Mining of natural cementstones in the Rosendale region stopped after the invention of the Portland cement manufacturing process, which can use a wider range of more easily quarried limestones.
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WL_cement_mine5.JPG
The strata in the Rosendale region are folded into a series of synclines and anticlines. In this photo we see the opposite limb of the anticline that was mined out in the previous photo. Note that here the strata are almost completely vertical.
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Glacial striations on a glacially polished surface of the Shawangunk conglomerate, Minnewaska State Park.
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Note the orientation of the glacial striations - they are approximately north-south, showing the direction of flow of glacial ice.
striation_outcrop.JPG
roche_moutonee.JPG
The glacially carved bedrock surface shows a distinctive pattern of smooth, angled surfaces to the north and steep, plucked surfaces to the south. This assymetrical form is called roche moutonee.
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The group standing at the Beacon Hill trail overlook.
Shawangunk_ridge.JPG
View north along the Shawangunk Ridge. Note the doubling of the ridge due to the folding of the rock layers.
Beacon_hill_view.JPG
View from the Beacon Hill overlook northwest across the Rondout Valley with the high peaks of the Catskills in the distance.
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View of the high peaks region of the Catskills across the Rondout Valley.
Beacon_hill_view3.JPG
View of the eastern edge of the Shawangunk ridge and the Wallkill Valley to the east.
roche_moutonee2.JPG
Bedrock outcrop near Lake Minnewaska showing distinctive roche moutonee form (shallow slope to the north, steep slope to the south).
Lake_Minnewaska.JPG
View south along Lake Minnewaska.
Minnewaska_outcrop.JPG
Bedrock outcrop of the Shawangunk conglomerate along the shore of Lake Minnewaska.