Earth Sciences Commons^™

Condensed And Expanded Sections In The Lower Mesaverde Clastic Wedge, Campanian Of Wyoming: Evidence For Tectonic Rectification Of Sea Level, Matthew W. Botzler

OES Theses and Dissertations

The stratigraphy of the Cretaceous Western Interior basin indicates that sea level oscillated during the late Cretaceous. The oscillations were polyharmonic, with periods ranging from millions of years to hundred thousands and ten thousands of years. However, there is disagreement over the extent to which sea level change was global in nature and the extent to which it was driven by local uplift or subsidence (tectonism). In orogenic regions where subsidence, sediment supply, and eustatic variation are all affecting sea level, comparisons of high and low frequency cycles can help to sort out forcing mechanisms. Low frequency eustatic sea level …

Middle Shoreface Intervals: Evidence Of Barred Nearshore Systems In He Stratigraphic Record, James V. Gravette

OES Theses and Dissertations

An interpretation for middle shoreface (MSF) intervals was developed by comparing MSF intervals from the Upper Cretaceous (Campanian) Blackhawk Formation, east-central Utah, with conceptual models proposed for modern nearshore areas. Specifically, MSF intervals identified within the Sunnyside Member were compared with MSF intervals identified within the Spring Canyon (Kamola and Van Wagoner, 1995) and the Aberdeen (Kamola, unpublished data) members.

A comparison of MSF interval data revealed that MSF intervals occur stratigraphically between upper and lower shore face deposits, disrupting the standard vertical succession for nearshore marine deposits (consisting of offshore, lower shore face, upper shore face, and foreshore deposits). …

Biostratigraphic Analysis Of Southern Florida's Plio-Pleistocene Shell Beds, Dalton L. Rasmussen

OES Theses and Dissertations

Four molluscan assemblage zones in southern Florida corresponding to the Pinecrest Sand Member of the Tamiami Formation, and the Caloosahatchee, Bermont and Fort Thompson shell beds were identified following quantitative and qualitative analyses of the fossil molluscan fauna. Twenty-eight bulk sediment samples collected from 16 localities across southern Florida were processed for fossil material, and yielded nearly 60,000 specimens belonging to 311 species. A Q-mode cluster analysis compared sediment samples on the basis of 188 species whose abundances had been converted to binary presence-absence form. The cluster analysis was run four times using the Jaccard and Dice similarity coefficients as …

Depositional Environment And Sequence Stratigraphic Interpretation Of Miocene St. Marys Formation, Calvert County, Maryland, John J. Blandin

OES Theses and Dissertations

The Miocene St. Marys Formation at Calvert Cliffs, Maryland is divided into four depositional packages made up of marine fades representing shallow shelf through intertidal conditions. These depositional packages are separated by five laterally persistent surfaces and were defined based on detailed depositional fades analysis of 24 measured sections, averaging 17 meters thick. These four packages make up two marine sequences, stratigraphic units bound above and below by surfaces of sea level fall. The lower sequence is composed of a single depositional package, while the upper sequence is composed of three upward-shallowing depositional packages (i.e. para-sequences). A fifth depositional package …

Seismic Stratigraphic Analysis Of The Upper Indus-Fan Complex A Model For Fan Development, Syed Firasat Shah

OES Theses and Dissertations

The seismic stratigraphic analysis of the upper Indus-Fan Complex has revealed the presence of six depositional sequences. Deposition of these sequences occurred primarily during the Miocene period. The Indus River drainage system that developed as a consequence of Himalayan orogeny transported the bulk of the sediments deposited in the Indus Fan. The distribution and thickness of the sequences of the upper Indus Fan are closely related to the canyon-channel systems. Seismic facies analysis of the slope has revealed the presence of a facies relationship that shows continued deepening from the time of deposition of slope fan to the latest deposits …

Lithofacies Of The Pliocene Yorktown Formation In The Vicinity Of Kingsmill On The James River, Virginia, Michael David Lawless

OES Theses and Dissertations

The Yorktown Formation beds which crop out along the James River in southeastern Virginia near Kingsmill and Carter's Grove are lithologically described in order to compare them with the "typical" Yorktown beds upriver in the area of Fort Boykins, Rushmere, and Cobham Wharf. Thirty-four stratigraphic sections are constructed of the bluffs along the river. The Yorktown beds in the area of Kingsmill and Cobham Wharf are divided into ten lithofacies: the silty sand facies (B), the Chesapecten facies (C), the Glycymeris facies (D), the Chama facies (E), the glauconitic biofragmental sand facies (F), the laminated silty clay facies (G), the …

Trace Elements In Northern Virginia Middle Ordovician Carbonates: Implications For Diagenesis, Ruth Ann Strauss

OES Theses and Dissertations

Ninety-three carbonate rock samples collected from four of the major lithofacies types present in the Middle Ordovician limestone sequence of northwestern Virginia were analyzed to investigate whether the lithofacies bear the geochemical signature of the depositional and/or the diagenetic environment. Significant variations in Cr, Fe, Mg, Mn and Sr concentrations exist among the major lithofacies types. Low levels of Sr in both New Market lithofacies are indicative of an open system during diagenesis. Dissimilar Fe and Mn concentrations between these, however, reflect water chemistry differences in the depositional environment. Increasingly greater Cr, Fe, Mn, and Sr concentrations in the Lincolnshire …

Foraminiferal Biostratigraphy And Paleoenvironmental Analysis Of The Anahuac Formation (Late Oligocene-Early Miocene) From A Deep Well In Vermilion Parish, Louisiana, Audrey Lynne Orndorff

OES Theses and Dissertations

In the subsurface of Vermilion Parish, Louisiana, sediments from the Anahuac Formation in the #1 J. W. Steen well are assigned an Upper Oligocene-Lower Miocene age based on planktonic foraminifera. Previous age determinations for sediments from this formation elsewhere range from Middle to Late Oligocene based on the presence of larger foraminifera contained within these strata. Planktonic foraminifera in Anahuac formation sediments in the #1 J. W. Steen well permit their assignment to an established worldwide zonation scheme and indicate that the age ranges from the Globorotalia kugleri Interval Zone (Upper Oligocene) to the Catapsydrax dissimilis Zone (Lower Miocene). Benthic …

Conodont Biostratigraphy Of The Cambrian-Ordovician Boundary Interval In The Northern Shenandoah Valley Of Virginia, U.S.A., Randall C. Orndorff

OES Theses and Dissertations

Conodonts collected from two measured sections in the northern Shenandoah Valley of Virginia indicate that locally the Cambrian-Ordovician boundary is within the upper part of the Conococheague Formation and that the Conococheague-Stonehenge formational contact as defined in this study, is diachronous in relation to the boundary. Using the generally accepted definition of the CambrianOrdovician boundary as at the base of the trilobite Missisguoia Zone or within the conodont Hirsutodontus hirsutus Subzone of the Cordylodus proavus Zone, it is found here that the boundary is 230 ft (70 m) below the formational contact at the Narrow Passage Creek section. Several North …

Stratigraphy And Textural Analyses Of A Beach Ridge Complex, Cape Henry, Virginia, Daniel Leland Oyler

OES Theses and Dissertations

Eight lithological units, documented from the analyses of 26 boreholes, comprise five laterally extensive horizons in the subsurface of Cape Henry, Virginia. Interpretations of the environments of deposition for those units are based upon textural and compositional features, fossils, thickness and distribution of strata, and previous reports about late Tertiary and Quaternary deposits in nearby areas. The incised, Pliocene Chowan River Formation (Unit H) underlies Pleistocene Units F and G which are concentrated in a buried river valley beneath Cape Henry. Estuarine Units D and E resulted from a marine transgression of the study area during the early Holocene. The …

Tectonic Implications Of Late Tertiary Strata Exposed Along The Piankatank River, Eastern Virginia, Daniel Stephen Lane

OES Theses and Dissertations

Biostratigraphic analysis of Late Miocene and Pliocene strata along the Piankatank River in eastern Virginia exposes a juxtaposition of the Eastover and Yorktown Formations. This structure is situated on a NE trending alignment of geological, geomorphic, and geophysical features which run from southern Virginia to northern Delaware. Tectonic jointing in isolated sandstone bodies and fracture controlled drainage patterns provide further evidence of post-middle Pliocene tectonism in the region. The lateral spacing of this structure from the Stafford and Brandywine fault zones and other linear features on the Coastal Plain strongly implies that a structural similarity exists between the Piankatank structure …