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Geology

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Masters Theses

Sequence stratigraphy

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Full-Text Articles in Physical Sciences and Mathematics

Depositional Facies And Sequence Stratigraphic Model For The Silurian Reefs, Michigan Basin, Usa, Zaid N. Nadhim Apr 2019

Depositional Facies And Sequence Stratigraphic Model For The Silurian Reefs, Michigan Basin, Usa, Zaid N. Nadhim

Masters Theses

Depositional models for the Silurian reefs in the Michigan Basin suggest that internal facies are either (i) randomly distributed within a symmetrical reef structure, or (ii) highly asymmetrical and strongly controlled by paleo-wind direction. To further test the applicability of these models, internal facies distributions were mapped using high-resolution core and log data in two sets of Silurian reefs. The results suggest that the relationship between reef geometry, facies distribution and proposed paleo-wind direction is more inconsistent than recently proposed. More specifically, facies descriptions from the Silurian reefs suggest the following. First, overall reef geometry and facies distributions are not …


Application Of Handheld Ed-Xrf For High-Resolution Chemostratigraphy In Texturally Homogeneous Carbonate Mudstones: Salina A-1 Carbonate (Silurian), Michigan Basin, Matthew A. Hemenway Jun 2018

Application Of Handheld Ed-Xrf For High-Resolution Chemostratigraphy In Texturally Homogeneous Carbonate Mudstones: Salina A-1 Carbonate (Silurian), Michigan Basin, Matthew A. Hemenway

Masters Theses

Handheld energy dispersive x-ray fluorescence spectrometry (ED-XRF) is routinely used to observe elemental variability in fine-grained siliciclastics but has been applied rarely in fine-grained carbonates. Here, ED-XRF chemostratigraphy is utilized in the texturally homogenous, mudstones of the Silurian A-1 Carbonate (A-1C), Michigan Basin. Previous studies on the A-1C focused on the stratigraphic relationship with the underlying Niagaran reefs, so little is known about the geological variability in the basin center. In this study, high-resolution elemental data from nine cores were integrated with petrographic and mineralogical observations to evaluate two hypotheses: (1) Texturally homogeneous, basin-center mudstones in the A-1C have spatially …


Paleogeographic And Paleoenvironmental Evolution Of Lacustrine And Fluvial Upper Triassic Zhangjiatan Shale Sequence, Ordos Basin, China, Qiuwan Yu Jan 2015

Paleogeographic And Paleoenvironmental Evolution Of Lacustrine And Fluvial Upper Triassic Zhangjiatan Shale Sequence, Ordos Basin, China, Qiuwan Yu

Masters Theses

"Detailed sequence stratigraphic and depositional systems analyses can effectively delineate factors and processes controlling deposition of fine-grained lacustrine sediments. Upper Triassic Zhangjiatan (ZJT) Shale Bed and adjacent strata in Ordos foreland basin was used as an example. A new depositional sequence model shows that the maximum regressive shoreline was more landward than that at the lowest lake-level. The study area is on the ramp margin, covering 100x90 km2. Thin sections, cores and well-logs of 80 wells are used to calibrate log signatures, document lithofacies, and interpret depositional facies in a sequence stratigraphic context. The entire sequence thickens from …