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Green River and Wasatch Formations (WYTgrw;0)

Geologic Formation in WY

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Lithology

Limestone

Conglomerate

Mudstone

Other (781 mi²)

Geologic Age

Eocene (56 Ma – 33.9 Ma ago)

Geologic Unit Label

Tgrw

Green River Formation (Thrust Belt) - Buff laminated marlstone and limestone, brown oil shale, and siltstone. Includes Angelo and Fossil Butte Members. Wasatch Formation (Thrust Belt) - Variegated mudstone and sandstone. Includes Tunp and Bullpen Members, other tongues and unnamed members, and main body (variegated red to gray, brown, and gray mudstone and sandstone; conglomerate lenses). Green River Formation (in southwest Wyoming) - Oil shale, light-colored tuffaceous marlstone, and sandstone. Wasatch Formation (in southwest Wyoming) - Drab to variegated claystone and siltstone, carbonaceous shale and coal, buff sandstone, arkose, and conglomerate. In northwestern part of Green River Basin is thick arkosic light-yellowish-tan sandstone intertonguing with pale-green to gray claystone and shale.

— USGS

Taxonomy

Classified As

Geologic Formation