Graphic correlation across a facies change marking the location of a middle to late Cenomanian ocean front

Conference · Mon Mar 01 00:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5933752

Fisher, C G ^[1]

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1. State Univ. of New York, Cortland, NY (United States). Dept. of Geology

An abrupt lithofacies change between calcareous shale and non-calcareous shale occurs in strata deposited in the mid-Cretaceous Greenhorn Seaway in the extreme southeastern corner of Montana, U.S.A. This strata, north of the Black Hills has previously been miss-correlated due to the extreme difficulty in locating unique continuous marker beds. Supplemental Graphic Correlation techniques of Lucy Edwards, which expand on those of Shaw, were employed in the difficult task of correlating across the Little Missouri River Valley. Precise correlation was necessary in order to interpret the cause of the lithofacies change. Edwards's use of non-unique event marker beds and the side-by-side graph method proved to be invaluable tools. Precise correlation across the facies change was accomplished using a combination of bentonite beds, calcarenite beds, ammonite species, foraminiferal and calcareous nannofossil assemblages. Supplemental Graphic Correlation techniques allowed the definition of twenty-five time slices and permitted the identification of an ocean front during each of these time slices.

• OSTI ID: 5933752
• Report Number(s): CONF-9303211-; CODEN: GAAPBC
• Journal Information: Geological Society of America, Abstracts with Programs; (United States), Vol. 25:2; Conference: 28. annual Geological Society of America (GSA) Northeastern Section meeting, Burlington, VT (United States), 22-24 Mar 1993; ISSN 0016-7592
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
GEOLOGIC DEPOSITS
LITHOLOGY
MAPPING
STRATIGRAPHY
MONTANA
SHALES
BENTONITE
COMPARATIVE EVALUATIONS
CRETACEOUS PERIOD
FORAMINIFERA
FOSSILS
GEOLOGIC HISTORY
GEOLOGIC STRATA
PALEONTOLOGY
ANIMALS
CLAYS
DEVELOPED COUNTRIES
EVALUATION
GEOLOGIC AGES
GEOLOGIC STRUCTURES
GEOLOGY
INORGANIC ION EXCHANGERS
INVERTEBRATES
ION EXCHANGE MATERIALS
MATERIALS
MESOZOIC ERA
MICROORGANISMS
NORTH AMERICA
PETROLOGY
PROTOZOA
ROCKS
SARCODINA
SEDIMENTARY ROCKS
USA
580000* - Geosciences