Sedimentation and diagenesis at a Late Cambrian biomere extinction horizon
Abstract
The base of the Eurekia apopsis Subzone of the Saukia Zone, slightly below the present Cambrian-Ordovician boundary, has been interpreted as a biomere extinction crisis for trilobites and conodonts. This boundary can be recognized to within two centimeters in platform carbonates in Utah, Nevada, Texas, and Oklahoma. Regional stratigraphy in West Utah reveals that this extinction horizon occurs within a shoaling upward sequence in which sedimentation was predominantly episodic. Shallow subtidal sedimentation, producing bioturbated mixed-skeletal wackestones and graded intraclastic grainsupportstones (tempestites), shifted to peritidal sedimentation through the boundary interval and for the duration of the E. apopsis Subzone. Associated lithofacies include sponge-dominated thrombolite mounds with tidal channels, sublittoral stromatolite reefs, and a restricted marine lagoon. The base of the E. apopsis Subzone in West Utah is a sharp contact but is interpreted as neither a disconformity nor a surface of subaerial exposure. In Texas, this boundary is a planar disconformity between biosparites. The bed underlying this surface displays features that reflect wholesale aragonite dissolution followed by two stages of inferred meteroic phreatic cementation. The surface is well washed and provided a clean substrate for epitaxial cementation across the boundary. The overlying basal strata of the E. apopsis Subzone are cementedmore »
- Authors:
- Publication Date:
- Research Org.:
- Univ. of Wisconsin, Madison (USA)
- OSTI Identifier:
- 6598007
- Report Number(s):
- CONF-8510489-
Journal ID: CODEN: GAAPB
- Resource Type:
- Conference
- Journal Name:
- Geol. Soc. Am., Abstr. Programs; (United States)
- Additional Journal Information:
- Journal Volume: 17; Conference: 98. annual meeting of the Geological Society of America, Orlando, FL, USA, 28 Oct 1985
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 58 GEOSCIENCES; CARBONATE ROCKS; DIAGENESIS; PALEONTOLOGY; PETROLOGY; STRATIGRAPHY; NEVADA; OKLAHOMA; TEXAS; UTAH; BIOLOGICAL EXTINCTION; CAMBRIAN PERIOD; GEOLOGIC HISTORY; LITHOLOGY; SEDIMENTATION; FEDERAL REGION IX; FEDERAL REGION VI; FEDERAL REGION VIII; GEOLOGIC AGES; GEOLOGY; NORTH AMERICA; PALEOZOIC ERA; ROCKS; SEDIMENTARY ROCKS; USA; 580100* - Geology & Hydrology- (-1989); 580300 - Mineralogy, Petrology, & Rock Mechanics- (-1989)
Citation Formats
Grimm, K A, Miller, J F, and Taylor, J F. Sedimentation and diagenesis at a Late Cambrian biomere extinction horizon. United States: N. p., 1985.
Web.
Grimm, K A, Miller, J F, & Taylor, J F. Sedimentation and diagenesis at a Late Cambrian biomere extinction horizon. United States.
Grimm, K A, Miller, J F, and Taylor, J F. 1985.
"Sedimentation and diagenesis at a Late Cambrian biomere extinction horizon". United States.
@article{osti_6598007,
title = {Sedimentation and diagenesis at a Late Cambrian biomere extinction horizon},
author = {Grimm, K A and Miller, J F and Taylor, J F},
abstractNote = {The base of the Eurekia apopsis Subzone of the Saukia Zone, slightly below the present Cambrian-Ordovician boundary, has been interpreted as a biomere extinction crisis for trilobites and conodonts. This boundary can be recognized to within two centimeters in platform carbonates in Utah, Nevada, Texas, and Oklahoma. Regional stratigraphy in West Utah reveals that this extinction horizon occurs within a shoaling upward sequence in which sedimentation was predominantly episodic. Shallow subtidal sedimentation, producing bioturbated mixed-skeletal wackestones and graded intraclastic grainsupportstones (tempestites), shifted to peritidal sedimentation through the boundary interval and for the duration of the E. apopsis Subzone. Associated lithofacies include sponge-dominated thrombolite mounds with tidal channels, sublittoral stromatolite reefs, and a restricted marine lagoon. The base of the E. apopsis Subzone in West Utah is a sharp contact but is interpreted as neither a disconformity nor a surface of subaerial exposure. In Texas, this boundary is a planar disconformity between biosparites. The bed underlying this surface displays features that reflect wholesale aragonite dissolution followed by two stages of inferred meteroic phreatic cementation. The surface is well washed and provided a clean substrate for epitaxial cementation across the boundary. The overlying basal strata of the E. apopsis Subzone are cemented with marine phreatic non-ferroan calcite and contain faunas that are strikingly dissimilar to those below.},
doi = {},
url = {https://www.osti.gov/biblio/6598007},
journal = {Geol. Soc. Am., Abstr. Programs; (United States)},
number = ,
volume = 17,
place = {United States},
year = {Tue Jan 01 00:00:00 EST 1985},
month = {Tue Jan 01 00:00:00 EST 1985}
}