Title

Petrographic Characteristics of Transgressive and Regressive Limestone of Upper-Pennsylvanian (Virgilian) Oread Cyclothem, NE Oklahoma and SE Kansas

Presenter Information

Lu Zhu

Department

Geosciences and Geological and Petroleum Engineering

Major

Geology

Research Advisor

Yang, Wan

Advisor's Department

Geosciences and Geological and Petroleum Engineering

Funding Source

Missouri S&T Opportunities for Undergraduate Research Experiences (OURE) Program

Abstract

Deltaic sandstones deposited during maximum-transgression and regression are expected to differ compositionally and texturally, because of different environmental conditions associated with sea-level changes. This hypothesis is tested by petrographic study of two sandstones from maximum-trangressive delta and two from regressive delta in NE Oklahoma. Data are compared to display their similarities by interpreting the controlling processes. All sandstones are feldspathic arenite. The lower maximum-trangressive sandstone is K-feldspar rich, less sorted, finer, less rounded, more symmetrical than the upper one. These characteristics conform with the stratigraphic stacking of the lower distal and upper proximal delta lobes, where upward coarsening trend and increased maturity are common during deltaic progradation. The lower regressive sandstone is finer, better sorted, better rounded, near symmetrical than the upper one. Field evidence indicates that the lower sandstone is wave dominated, whereas the upper river dominated, conforming to the overall progradational pattern. The differences in wave and river processes and energy regime are probably the causes of an upward-decreasing textural maturity between the two sandstones. Maximum-trangressive sandstones are more texturally heterogeneous than regressive sandstones, indicating more variable environmental conditions in regressive-deltaic environment. Overall the deltaic sandstones of Oread Cyclothem are feldspar-rich, texturally submature. The petrographic characteristics suggest that the lithology and location of provenance, transport distance, and deltaic sedimentary processes are the dominant controls, rather than sea-level changes.

Biography

Lu, a geology student at Missouri S&T, was transferred to Rolla from China University of Petroleum (East China) in 2010. She is a member of Epsilon Sigma Gamma honor society.

Research Category

Sciences

Presentation Type

Poster Presentation

Document Type

Poster

Location

Upper Atrium/Hallway

Presentation Date

10 Apr 2012, 9:00 am - 11:45 am

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Apr 10th, 9:00 AM Apr 10th, 11:45 AM

Petrographic Characteristics of Transgressive and Regressive Limestone of Upper-Pennsylvanian (Virgilian) Oread Cyclothem, NE Oklahoma and SE Kansas

Upper Atrium/Hallway

Deltaic sandstones deposited during maximum-transgression and regression are expected to differ compositionally and texturally, because of different environmental conditions associated with sea-level changes. This hypothesis is tested by petrographic study of two sandstones from maximum-trangressive delta and two from regressive delta in NE Oklahoma. Data are compared to display their similarities by interpreting the controlling processes. All sandstones are feldspathic arenite. The lower maximum-trangressive sandstone is K-feldspar rich, less sorted, finer, less rounded, more symmetrical than the upper one. These characteristics conform with the stratigraphic stacking of the lower distal and upper proximal delta lobes, where upward coarsening trend and increased maturity are common during deltaic progradation. The lower regressive sandstone is finer, better sorted, better rounded, near symmetrical than the upper one. Field evidence indicates that the lower sandstone is wave dominated, whereas the upper river dominated, conforming to the overall progradational pattern. The differences in wave and river processes and energy regime are probably the causes of an upward-decreasing textural maturity between the two sandstones. Maximum-trangressive sandstones are more texturally heterogeneous than regressive sandstones, indicating more variable environmental conditions in regressive-deltaic environment. Overall the deltaic sandstones of Oread Cyclothem are feldspar-rich, texturally submature. The petrographic characteristics suggest that the lithology and location of provenance, transport distance, and deltaic sedimentary processes are the dominant controls, rather than sea-level changes.