University of Illinois Urbana-Champaign

Stratigraphy, Depositional History, and Brachiopod Paleontology of Virgilian Strata of East-Central Illinois

Weibel, Carl Pius

This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.

Permalink

https://hdl.handle.net/2142/77688

Description

Title
Stratigraphy, Depositional History, and Brachiopod Paleontology of Virgilian Strata of East-Central Illinois
Author(s)
Weibel, Carl Pius
Issue Date
1988
Doctoral Committee Chair(s)
Langenheim, Ralph L., Jr.
Department of Study
Geology
Discipline
Geology
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
  • Geology
  • Paleontology
Language
eng
Abstract
  • The Virgilian outlier, upper Mattoon Formation, in east-central Illinois consists of alternating marine and nonmarine strata divided into eight modified cyclothems: Omega, Shumway, Bogota, Newton, Mint Creek, Greenup, Toledo, and Woodbury. The modified cyclothems are recognized with lower boundaries at top of coal or base of the lowest marine stratum. The perceived stratigraphic succession is revised, incorporating cyclotherms and formal members, and utilizes outcrop and newly acquired subsurface data.
  • Cyclothems containing black, fissile shale were deposited in successive environments of (1) local, shallow, tidal lagoon, (2) shallow, nearshore, open marine, (3) offshore, marine, (4) shallow, nearshore, open marine, (5) subaqueous deltaic progadation, and (6) coastal plain progradation. Marine units in cyclothems lacking the shale were deposited in either shallow, nearshore, open marine or in shallow, offshore, open marine environments. Analysis of the Bogota cyclothem indicates slow transgression consisting of a series of progressively more widespread advances with minor retreats.
  • Limestone petrography indicates diagenesis in successive environments of marine phreatic, saturated meteoric phreatic, and burial environment. Some limestones included diagenesis in mixed marine-freshwater, unsaturated meteoric phreatic, or meteoric vadose environments. Diagenetic sequences are compatible with the inferred depositional environments.
  • Shumway, Bogota, Newton, and Mint Creek cyclothems correlate with equivalent cyclic sequences in the midcontinent and north-central Texas. Biostratigraphic correlation of 21 brachiopod species, indicates strata above the Omega Limestone Member are middle to upper Virgilian, supporting the extrabasinal, lithostratigraphic correlation. Inability to correlate with cyclic strata in New Mexico and Nevada suggests correlable Virgilian cyclothems are restricted to the craton, or that eustatic fluctuations are not yet discernable in the these platform carbonates. This study supports, in part, the validity of widespread, glacial-eustatic, cyclothemic deposition.
Graduation Semester
1988
Type of Resource
text
Permalink
http://hdl.handle.net/2142/77688

Owning Collections

Graduate Dissertations and Theses at Illinois PRIMARY
Graduate Theses and Dissertations at Illinois
Dissertations and Theses - Geology