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Title: Cretaceous biostratigraphy in the Wyoming thrust belt

Abstract

Biostratigraphy is essential to exploration for oil and gas in the Wyoming thrust belt because fossils provide a temporal framework for interpretation of events of faulting, erosion, sedimentation, and the development of hydrocarbon traps and migration pathways. In the Cretaceous section, fossils are especially useful for dating and correlating repetitive facies of different ages in structurally complex terrain. The biostratigraphic zonation for the region is based on megafossils (chiefly ammonites), which permit accurate dating and correlation of outcrop sections, and which have been calibrated with the radiometric time scale for the Western Interior. Molluscan and vertebrate zone fossils are difficult to obtain from the subsurface, however, and ammonities are restricted to rocks of margin origin. Palynomorphs (plant microfossils) have proven to be the most valuable fossils in investigations of stratigraphy and structures in the subsurface of the thrust belt because palynomorphs can be recovered from drill cuttings. Palynomorphs also are found in both marine and nonmarine rocks and can be used for correlation between facies. In this paper, stratigraphic ranges of selected Cretaceous marine and nonmarine palynomorphs in previously designated reference sections in Fossil Basin, Wyoming, are correlated with the occurrence of ammonities and other zone fossils in the samemore » sections. These correlations can be related to known isotopic ages, and they contribute to the calibration of palynomorph ranges in the Cretaceous of the Western Interior.« less

Authors:
 [1];
  1. (U.S. Geological Survey, Denver, CO)
Publication Date:
OSTI Identifier:
6413708
Alternate Identifier(s):
OSTI ID: 6413708
Resource Type:
Journal Article
Journal Name:
Mt. Geol.; (United States)
Additional Journal Information:
Journal Volume: 19:3
Country of Publication:
United States
Language:
English
Subject:
02 PETROLEUM; 03 NATURAL GAS; GEOLOGIC STRUCTURES; STRATIGRAPHY; SEDIMENTARY ROCKS; AGE ESTIMATION; WYOMING; CRETACEOUS PERIOD; EXPLORATION; FOSSILS; GEOLOGIC TRAPS; MAPPING; NATURAL GAS; PALEONTOLOGY; PETROLEUM; ENERGY SOURCES; FEDERAL REGION VIII; FLUIDS; FOSSIL FUELS; FUEL GAS; FUELS; GAS FUELS; GASES; GEOLOGIC AGES; GEOLOGY; MESOZOIC ERA; NORTH AMERICA; ROCKS; USA 020200* -- Petroleum-- Reserves, Geology, & Exploration; 030200 -- Natural Gas-- Reserves, Geology, & Exploration

Citation Formats

Nichols, D.J., and Jacobson, S.R. Cretaceous biostratigraphy in the Wyoming thrust belt. United States: N. p., 1982. Web.
Nichols, D.J., & Jacobson, S.R. Cretaceous biostratigraphy in the Wyoming thrust belt. United States.
Nichols, D.J., and Jacobson, S.R. Thu . "Cretaceous biostratigraphy in the Wyoming thrust belt". United States.
@article{osti_6413708,
title = {Cretaceous biostratigraphy in the Wyoming thrust belt},
author = {Nichols, D.J. and Jacobson, S.R.},
abstractNote = {Biostratigraphy is essential to exploration for oil and gas in the Wyoming thrust belt because fossils provide a temporal framework for interpretation of events of faulting, erosion, sedimentation, and the development of hydrocarbon traps and migration pathways. In the Cretaceous section, fossils are especially useful for dating and correlating repetitive facies of different ages in structurally complex terrain. The biostratigraphic zonation for the region is based on megafossils (chiefly ammonites), which permit accurate dating and correlation of outcrop sections, and which have been calibrated with the radiometric time scale for the Western Interior. Molluscan and vertebrate zone fossils are difficult to obtain from the subsurface, however, and ammonities are restricted to rocks of margin origin. Palynomorphs (plant microfossils) have proven to be the most valuable fossils in investigations of stratigraphy and structures in the subsurface of the thrust belt because palynomorphs can be recovered from drill cuttings. Palynomorphs also are found in both marine and nonmarine rocks and can be used for correlation between facies. In this paper, stratigraphic ranges of selected Cretaceous marine and nonmarine palynomorphs in previously designated reference sections in Fossil Basin, Wyoming, are correlated with the occurrence of ammonities and other zone fossils in the same sections. These correlations can be related to known isotopic ages, and they contribute to the calibration of palynomorph ranges in the Cretaceous of the Western Interior.},
doi = {},
journal = {Mt. Geol.; (United States)},
number = ,
volume = 19:3,
place = {United States},
year = {1982},
month = {7}
}