|Latitude & Longitude (WGS84):||40° 51' 3'' North , 73° 58' 14'' West|
|Latitude & Longitude (decimal):||40.85083,-73.97056|
|Locality type:||Road Cutting|
|Köppen climate type:||Cfa : Humid subtropical climate|
This locality was a massive, deep roadcut into the Palisades diabase cliffs to accomodate the interstate highways and the lower level installation of the George Washington bridge. The excavations encountered some coarsely crystallized and vuggy areas of the diabase.
33 valid minerals.
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
174.1 - 201.3 Ma
Age: Early Jurassic (174.1 - 201.3 Ma)
Description: Fine-grained to aphanitic dikes; medium- to coarsegrained, subophitic discordant stock-like intrusions of dark-greenish-gray to black diabase; and plugs of dark gray, concordant to discordant sheetlike, medium- to coarse-grained, quartz-rich to albite-rich granophyre (map unit Jg). The chilled margins of diabase masses are aphanitic to very fine grained. Diabase is dense, hard, and sparsely fractured. It is composed mostly of plagioclase (An50-70), clinopyroxene (mostly augite) and magnetiteñilmenite. Accessory minerals include apatite, quartz, alkali feldspar, hornblende, titantite, and zirocon. Olivine is rare. Within about 200 m (655 ft) above and 150 m (490 ft) below the large diabase sheets, red mudstones are typically metamorphosed into indurated, bluish-gray hornfels commonly with clots or crystals of tourmaline or cordierite, whereas argillitic siltstone is metamorphosed into brittle, black, very fine grained hornfels, Sheetlike intrusions are as much as 360 to 400 m (1,180-1,310 ft) thick. Dikes range in thickness from 3 to 15 m (10-50 ft) and several kilometers (miles) long. Thickness of the stocklike bodies is unknown.
Comments: Units Jd and Jg are described together on printed map. Used same description for both, but split them into seperate units.
Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052. 
201.3 - 252.17 Ma
|Mesozoic intrusive rocks|
Age: Triassic (201.3 - 252.17 Ma)
Stratigraphic Name: Palisades Sill
Lithology: Intrusive igneous rocks
Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529.