Physical Sciences and Mathematics Commons^™

The Evolution From Late Miocene West Salton Detachment Faulting To Cross-Cutting Pleistocene Oblique Strike-Slip Faults In The Sw Salton Trough, Southern California, Alexander N. Steely

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Field studies in the southwest Salton Trough between Yaqui Ridge and Borrego Mountain show that the West Salton detachment fault was active during the Pliocene and may have initiated during the latest Miocene. At Yaqui Ridge dominantly east-directed extension is recorded by slickenlines on the NW-striking detachment fault, and shows that the fault is actually a low-angle dextral oblique strike-slip fault. Crustal inheritance is responsible for the position of the fault at Yaqui Ridge, which reactivates a late Cretaceous reverse-sense mylonite zone at map scale.

Late Miocene to Pliocene basin fill deposits at Borrego Mountain display progressive unconformities, contain detritus …

Implications Of Late Pleistocene Climatic Change On The Morphological Variations Of The Neanderthal, Dawn Marie Bradley

Geosciences Theses

In this research, the relationship of climatic changes between 130k to 28k years BP to concurrent morphological variations in Neanderthals was tested. Traditional anthropological studies attribute robust Neanderthal morphological traits as an adaptation to a cold environment. A database of previously completed terrestrial paleoclimatic reconstructions in Europe and the Mediterranean was compiled and used to create a series of GIS-generated timeslice maps. Regional climatic conditions were then related to changes in Neanderthal appearances, morphology and disappearances as evident in the archaeological record. To establish climatic conditions, existing studies were compiled from two regions: Europe and the Mediterranean. The European data …

Continuous Late Pleistocene Paleoclimate Record From The Southwest African Margin: A Multi-Proxy Approach, Julia Keegan Shackford

Geosciences Theses

Late Pleistocene sediments recovered from ODP Leg 175, Site 1085 are used to generate a high-resolution (500 yr) record of continental climate change in Southern Africa. The location of Site 1085, the SW African continental slope, provides a continuous hemipelagic section with a significant terrigenous component. Terrigenous sediments are transported via fluvial and/or eolian transport mechanisms with MIS 1 being dominated by eolian transport. Analyses, including grain-size, color reflectance, biogenic sediment geochemistry (%CaCO3, %TOC, and C/N), bulk sediment geochemistry, and clay mineralogy, are used to identify continental climate conditions in southern Africa. Analyses indicate glacial/interglacial variation. Median grain-size peaks are …

Geology Of The Tierras Blancas Area In The Southeastern Acambay Graben, Central Mexico, Lonnie T. Mercer

Theses and Dissertations

Pliocene-Pleistocene sediments in the southeastern Acambay graben, central Mexico have yielded mammal fossils, including Equus simplicidens, cf. Rhynchotherium, ?Camelops, Mammuthus sp., Bison sp., and Antilocapra sp. The fossiliferous sediments include a period of lacustrine sedimentation in the late Pliocene-early Pleistocene that interrupted fluvial and alluvial sedimentation during the early Pliocene and Pleistocene. The sediments deposited in this late Pliocene paleolake record a history of lake level fluctuations, shown by lithologic variations in lacustrine sediments and abundance of vertebrate burrows. Volcanic and tectonic events in the Acambay graben were the major controls on sedimentation during Pliocene-Pleistocene time. …

A Large Late Pleistocene Outburst Flood From Pluvial Lakes Alvord And Coyote Into The Owyhee River, Oregon, Deron Torrey Carter

All Master's Theses

A large late-Pleistocene flood traveled into the Owyhee River as a result of a rise and subsequent outburst from pluvial Lake Alvord in southeastern Oregon. Lake Alvord breached Big Sand Gap after reaching an elevation of 1292 m, releasing 11.3 km3 into the adjacent Coyote Basin before stabilizing at an elevation of about 1280 m. Overflow then spilled out of the Coyote Basin through two outlets at 1278 m and into the Crooked Creek drainage of the Owyhee River. The flood created a series of deeply incised canyons, scabland topography and deposited numerous boulder bars containing imbricated clasts up to …

Aminostratigraphy Of Thatcher Basin, Se Idaho: Reassessment Of Pleistocene Lakes, Amy Hochberg

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Quaternary geologic history of Lake Thatcher, southeastern Idaho, is pivotal in determining when the Bear River carved its through-flowing channel into the Bonneville Basin. Bright's reconstruction of the history of Lake Thatcher was based on ¹⁴C dates that are now known to be inaccurate. Lava Creek B ash found interbedded with lacustrine sediment suggests that Thatcher Basin contained a lake well before Bright's original estimate of 34 ka.

D/L ratios, which measure the extent of racemization in fossil gastropods, in conjunction with paleosols and tephra, were used to correlate between four localities across Thatcher Basin to reassess lake-level …

Boulder Streams, Debris Fans, And Pleistocene Climate Change In The Blue Ridge Mountains Of Central Virginia, G. Richard Whittecar, Derek W. Ryter

OES Faculty Publications

The west slope of the Blue Ridge mountains in central Virginia is a polygenetic landscape containing interglacial and periglacial features. This paper proposes a general model relating the distribution and origin of hillslope and toeslope Quaternary landforms to climatically influenced geomorphic processes. Two generations of interglacial debris fans in the study area differ in their degree of soil development and clast weathering. Boulder streams, which clog debris flow chutes for the upper debris fans, are interpreted as solifluction features formed during successive periglacial episodes. Growth of the boulder streams and associated talus slopes can influence the magnitude and frequency of …

Parameters Controlling Sediment Composition Of Modern And Pleistocene Jamaican Reefs, Stephen K. Boss

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Recent carbonate sediments from Jamaican north coast fringing reefs display variation in constituent composition, texture, and mineralogy related to their location on the reef. Samples were collected along lines which traversed the back reef and fore reef (0.5m to 70m).

The sediment is dominated by highly comminuted coral fragments, plates of the calcareous green alga, Halimeda, coralline algae, and the encrusting Foraminifera, Homotrema rubrum, with lesser amounts of other taxonomic groups (Foraminifera; molluscs; echinoderms). Relative abundances of these biotic components vary between sites. Q-mode cluster analysis indicates that constituent composition can be used to delineate the different reef …

Explorations, Vol. 1, No. 2, Jim I. Mead, Emilee M. Mead, Carol J. Bombard, Ronald B. Davis, Marcella H. Sorg

Explorations — A Journal of Research

The cover print is a multi-plate colored etching entitled Skull and Sun Dial, by Susan Groce, Associate Professor of Art at the University of Maine at Orono, where she teaches Printmaking and Drawing.

Articles include:

"The Quaternary"

"Ice Age Plants and Animals: Secrets of the Colorado Plateau," by Jim I. Mead and Emilee M. Mead

"Finding the Facts: Pieces of the Puzzle"

"On Location: In Search of the First Americans"

"A Temporal Vegetational Continuum: From Tundra to Forest," by Carole J. Bombard for Ronald B. Davis

"Anatomy of an Excavation," by Robson Bonnichsen

"What the Bones Tell Us," by …

Stratigraphy And Depositional Environments Of A Late Pleistocene Barrier Island Complex, Southeastern Virginia, Alan K. Jasper

OES Theses and Dissertations

The Norfolk, Kempsville, and Sand Bridge Formations beneath the HIckory Scarp of southeastern Virginia are reinterpreted as representing one glacio-eustatic transgressive cycle. The timing of this transgressive event is set during the earliest Wisconsinan. The formations were previously interpreted as unconformable overlying one another. The Norfolk-Kempsville unconformity is actually a diagenetic boundary. Evidence is presented which indicates that the Kempsville Scarp area should be reduced to member status or dropped entirely.

The Succession Of Late Cenozoic Volcanic Ashes In The Great Plains: A Progress Report, John Boellstorff

School of Natural Resources: Faculty Publications

No abstract provided.

Guidebook To The Late Pliocene And Early Pleistocene Of Nebraska, T. M. Stout, H. M. Degraw, L. G. Tanner, K. O. Stanley, W. J. Wayne, J. B. Swinehart

Conservation and Survey Division

No abstract provided.

The Red Cloud Sand And Gravel, A New Pleistocene Formation In Nebraska, C. Bertrand Schultz, Eugene C. Reed, A. L. Lugn

Conservation and Survey Division

Recent studies of the stratigraphy and paleontology of the Pleistocene of Nebraska have resulted in additional data that require further clarification and partial revision of the Grand Island sand and gravel formation (1,2) in order that there may be no condusion as the results of varying usage of the term.

The Geologic History Of The Bison In The Great Plains (A Preliminary Report), C. Bertrand Schultz, W. D. Frankforter

Bulletin of the University of Nebraska State Museum

THE GEOLOGIC history of the bison in North America is a subject which has received little attention to date. Osteological rather than geological problems have been the main concern of most writers who have so far published. If the geologic history of the bison is to be learned, it will be necessary to devote more time and effort in the field in determining the age of the deposits in which various specimens have been discovered and in making more extensive collections from deposits of known age. Unfortunately the majority of the type specimens have been surface finds and little attempt …

The Pleistocene Geology Of Nebraska, A. L. Lugn

Conservation and Survey Division

No abstract provided.