The Alex Bay Cut - viewer.gigamacro.com
This roadcut, near Alexandria Bay, New York, exposes the "Great Unconformity" between the basal Cambrian Potsdam Sandstone and the underlying Precambrian gneisses of the Frontenac Arch. The unconformity is near the base of the roadcut and can be seen to preserve some evidence of paleotopography on the Cambrian erosion surface.
The Great Unconformity in Ontario - University of Toronto
A superb, easily accessible outcrop 4 kilometres east of Alexandria Bay on Highway 12 in New York State near the St. Lawrence River and the Canada-US border exposes Potsdam resting on Precambrian gneisses below which in place are deeply weathered.
Thousand Islands Rocks > Thousand Islands Life Magazine > …
Unconformities – Geology Pics
View of the Great Unconformity in the Grand Canyon. Towards the bottom of the photo, it’s a nonconformity between the Cambrian Tapeats Sandstone and the Proterozoic metamorphic rocks (notice the granitic sill); In the middle of the photo, it’s an angular unconformity where the Tapeats sits on top tilted Hakatai Shale.
Alex Bay Road Cut EarthCache - Geocaching
2009年1月8日 · The contact displayed in the Alex Bay cut is an angular unconformity of profound dimension. The rocks below are 1100 million years old, and the Potsdam is more than nearly 500 million years old; therefore the contact represents a 600 million-year time gap!
The Great Unconformity | "The Great Unconformity" is …
2009年8月4日 · "The Great Unconformity" is a vast geological feature extending across several states in the Southwest. It is the evidence of an ancient land …
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1000 Islands Ecology - Geology of the Thousand Islands
The Paleozoic succession of sedimentary rocks in the Thousand Islands region lies with marked unconformity upon the much older igneous and metamorphic rocks of the Precambrian, a typical relationship of Paleozoic to Precambrian that exists around the periphery of the Canadian Shield from Labrador, across the northern edges of the Great Lakes ...
pictures of unconformities, unconformity, geology, …
Photos of Unconformities Unconformities speak to great lengths of geologic time in the rock record because they are depositional surfaces between rocks of different ages --and so represent periods of missing rock record.
Atlas of Unconformities: A Guide to Geological Gaps in …
2025年2月4日 · The unconformity at Portskerra is an erosional surface, where the ORS fills paleotopographic lows and drapes the intervening highs. Numbered sites refer to the thumbnail images below. Sites 1 (left) to 4 as shown in the …
Sunken Rock Lighthouse, New York at …
The light-station at Sunken Rock, St. Lawrence River, New York, consists of a tower and boathouse located on a rock about half a mile below Alexandria Bay. There is no keeper’s dwelling there nor land owned by the United States upon …