WebNov 1, 1989 · Carbon-isotopic compositions of total carbonate, inoceramid carbonate, micritic carbonate, secondary cements, total organic carbon, and geoporphyrins have … WebDuring the late Cenomanian and early Turonian, the Greenhorn transgression floodedtheNorthAmericanforelandbasin to form a relatively shallow seaway (Fig. 1 ). This allowed for the deposi- tion of rhythmically bedded sequences, including organic-rich strata of the Greenhorn Formation and its equivalents.
Graneros Shale - Wikipedia
WebNov 18, 2024 · The formation is soft and breaks down easily; therefore forms no salient topographic features. In the region of greatest development northeast of Silver City, it is cut by countless dikes that form a network of low ridges separated by shale valleys. The Greenhorn Limestone or Greenhorn Formation is a geologic formation in the Great Plains Region of the United States, dating to the Cenomanian and Turonian ages of the Late Cretaceous period. The formation gives its name to the Greenhorn cycle of the Western Interior Seaway. See more The formation was named for the Greenhorn Station on Greenhorn Creek in Colorado in 1896 by Grove Karl Gilbert; and it is the namesake of the Greenhorn Marine Cycle of the Cretaceous Western Interior Seaway. … See more The formation is recognized for its sequence of index fossils, including oysters, Ammonoidea, Belemnitida, and Inoceramidae. • Ammonoidea and Belemnitida were common, free-swimming pelagic predators, reflecting abundant … See more The Greenhorn Formation is characterized as shale to chalky shale, light bluish-gray in color, with rhythmically repeating beds of chalk or limestone … See more • Earth sciences portal • Paleontology portal • Dinosaurs portal • Cretaceous portal See more eastern time in texas
Greenhorn Formation (NMKgh;0) - USGS
WebThe lower Greenhorn Formation is characterized by dark-colored thinly laminated shale with rare biogenic and current-formed structures. It was deposited by pelagic settling in relatively quiet waters in anaerobic conditions. Rare storms reworked the sediments producing thin bioturbated intervals and thin limestone beds. WebThis study focuses on the application of carbon isotope and elemental stratigraphy to the Greenhorn - Carlile - Niobrara Formation interval, with analysis of seven cores in the Denver Basin and one core in the Washakie Basin. Carbon isotope stratigraphy has been shown to exhibit lithology independent chronostratigraphic correlative capabilities ... WebGreenhorn Formation (Kgr): Gray to light gray calcareous shale and shaly marl with thin beds of limestone. Shale contains white to pink calcareous specks. Marine. Thickness as … eastern time in central