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Shale, limestone and sandstone mark the Permian rocks of this period along with gypsum and halite deposits that suggest rapid desiccation in an arid climate. Nebraska transitioned to terrestrial conditions by 275 million years ago (Ma), with limited marine activity, coal swamps and paleosols preserving the climate of the period.
Group or Formation Period Notes Admire Group/Falls City: Carboniferous: Admire Group/Falls City Limestone Carboniferous: Admire Group/Janesville Shale Carboniferous: Admire Group/Onaga Shale
The Altamont Limestone is a geologic formation in Nebraska. It preserves fossils dating back to the Carboniferous period. See also
The lowest, oldest deposits filled in the shallow valleys of the weathered rocks that were exposed at that time, [7] which ranged in age from Cretaceous in Nebraska and Kansas to Permian in Texas. As the rivers built up the alluvial fans, subsurface water circulation varied, resulting in localized formation of caliche, and shallow lakes formed ...
Leaders of states in the U.S. which have significant mineral deposits often create a state mineral, rock, stone or gemstone to promote interest in their natural resources, history, tourism, etc. Not every state has an official state mineral, rock, stone and/or gemstone, however.
The Cottonwood Limestone is a marine limestone and calcareous shale, laterally persistent, bench-forming, and notably and consistently showing abundant fossils. An outstanding example of uniformity of thickness over considerable areas, the outcrop of the Cottonwood Limestone over a distance of 150 miles from Nebraska to central Kansas is ...
Named from exposures south of Howe, Nebraska, the Howe Limestone member is a grey limestone, 4-5 feet thick, that weathers to buff or slightly yellow. The limestone exhibits brachiopods, baculites, and larger bivalve mollusks. [3] The environment was an open, but very shallow sea with very little in the way of terrogenous sediments.
As the Pahasapa is a marine limestone, the fossils it contains are primarily brachiopods and scattered corals, [1] along with some crinoid plates, gastropods, and bryozoans. [8] Corals are chiefly Syringopora , and are found generally found near the gradational contact with the Englewood Formation.