Spelling suggestions: "subject:"eology, estratigraphic -- pleistocene."" "subject:"eology, estratigraphic -- leistocene.""
1 |
The Pleistocene loesses of a part of the Junction City quadrangleCrumpton, Carl F. January 1951 (has links)
Call number: LD2668 .T4 1951 C7 / Master of Science
|
2 |
The stratigraphy and sedimentation of the pleistocene section of the May Stone and Sand Company, Inc., Ardmore Avenue Quarry, Fort Wayne, Allen County, IndianaLacy, Stephen L. January 1986 (has links)
The Pleistocene section exposed in the May Stone and Sand Company, Inc., Ardmore Avenue quarry rests in the upper reaches of the Wabash-Erie Channel. The section consists of two distinct till units which are covered by a thick outwash deposit. Analysis of the tills has led to the assignment of the lower till to the Trafalgar Formation, while the upper till is assigned to the Lagro Formation. The 13- to 16-foot outwash unit shows evidence of rapid drainage which may be related to the catastrophic drainage of glacial Lake Maumee. Isolated mud to muck inclusions in the top eight feet of the section show the final depositional environment of the channel. These deposits were produced near the end of late Wisconsinan time. The last major event in the area was the stream piracy of the St. Joseph and Ste. Mary's Rivers by the Maumee River, in Late Wisconsinan or Recent time.
|
3 |
Late Pleistocene and postglacial sedimentation and stratigraphy of deep-sea environments off OregonDuncan, John Russell Jr 03 April 1968 (has links)
Graduation date: 1968
|
4 |
Geochemical evolution of groundwater in the Pleistocene limestone aquifer of BarbadosJones, Ian Christopher 28 August 2008 (has links)
Not available / text
|
5 |
Late Pleistocene reef limestones, Northern Barbados, W.I.James, Noel P. January 1971 (has links)
No description available.
|
6 |
Late Pleistocene reef limestones, Northern Barbados, W.I.James, Noel P. January 1971 (has links)
No description available.
|
7 |
Stratigraphic geology and depositional environments of the 111 Ranch area, Graham County, ArizonaSeff, Philip, 1923- January 1962 (has links)
No description available.
|
8 |
Late Pleistocene and recent chronologies of Playa lakes in Arizona and New MexicoLong, Austin,1936- January 1966 (has links)
A stratigraphic radiocarbon study at the Wilicox Playa and vicinity in Cochise County, southeastern Arizona has revealed a sedimentary sequence reflecting the lake level chronology of ancient Lake Cochise. The lower green clay was deposited in a lake at least 30 miles long from before 30,000 years ago until about 13,000 years ago. A marl formation which began depositing about 25,000 years ago and continued until the lake diminishe to about its present state 13,000 years ago, indicates a warm, moist climate at that time. The period from 13,000 B.P. (before present) and 11,000 B.P. was one of alluvial deposition north of the playa and channel cutting east of the playa. An upper green clay, 6 to 8 inches thick, represented the final phase of Lake Cochise, lasting from 11,500 B.P. until 10,500 B.P. A thin marl layer was deposited during this phase, indicating warm moist conditions again. The lake rapidly receded, some playa sediments deflated from the surface, and dunes formed north of the playa. Preliminary studies of two playas near Lordsburg, New Mexico and one at the San Augustin Plains, New Mexico, indicate these fluctuations were responding to a general climate change rather than isolated tectonic disturbances. The climate chronology concluded from this study is consistent with known climatic variations in the world.
|
9 |
The dietary behaviour of early pleistocene bovids from Cooper's Cave and Swartkrans, South AfricaSteininger, Christine Marrie 06 March 2012 (has links)
Ph.D., Faculty of Science, University of the Witwatersrand, 2011 / There is ongoing speculation about how an increasingly arid environment contributed to the extinction of Paranthropus robustus, given that a mosaic landscape with a major part of the area consisting of predominantly open grassland environment accompanied by an escalating cooler drier climate remains the persistent palaeoecological reconstruction for this species. It has been suggested that P. robustus, a dietary specialist, was not able to adapt to an increasingly xeric habitat. This notion has been challenged by recent multi-disciplinary research on P. robustus remains, including stable light isotope and dental microwear analyses, which portray a more complex diet. Paranthropus robustus is present in a number of key fossil assemblages spanning the period ca. 1.8 to 1.0 Ma. Analysis of the stable carbon isotope composition of bioapatites and dental microwear texture analysis of different bovid taxa, associated with P. robustus remains from five discrete deposits, were used to reconstruct dietary behaviour and by inference availability of local resources.
The overall pattern emerging from the bovid data indicates a more mixed and varied diet than previously thought, suggesting a heterogeneous environment, and hence a less static ecological profile for Paranthropus. The significant occurrence of mixed diets and relatively few obligate C4 grazers suggest that although C4 grasses were available in a mosaic environment, a C4-dominated ecosystem was not present. Swartkrans Member 2 (ca. 1.6 Ma) contains substantially more C3 feeders than other P. robustus deposits, signifying a vegetation community structure that was more C3-dominated than the other deposits. There is an apparent indication of shifting vegetation structure between
P. robustus deposits. Thus, despite its derived craniodental morphology, P. robustus seems to have thrived through a range of climatic and ecological shifts by selecting from a variety of available foods present on the landscape.
|
10 |
Seismic sequence stratigraphy and tectonic evolution of southern hydrate ridgeChevallier, Johanna 18 February 2004 (has links)
A 3D seismic volume was acquired summer 2000 over the southern end of
Hydrate Ridge (FIR), an anomalously shallow ridge 100 km offshore Newport,
Oregon. The survey followed a succession of scientific expeditions aimed at
studying the gas hydrates present in the shallow subsurface that gave the name to
the ridge. This thesis consists of a seismic sequence analysis of the high-resolution
(125 Hz) 3D survey. Identification of seismic units and interpretation of
depositional sequences observed on the seismic sections is presented. The sequence
analysis is compared with the results from nine sites cored during ODP Leg 204
during summer 2002. The first objective is to document in detail the stratigraphy of
the ridge so that we can compare it with the gas hydrate distribution. The second is
to reconstruct the structural evolution through time of this complex anticline as
inferred from the depositional history. The result is a time series of structural
evolutionary cross-sections as well as a series of paleo-bathymetric maps revealing
the development of and interplay between the structures now buried in the
subsurface of southern HR. The structural evolutionary diagrams show the
existence of three anticlines, interpreted as thrust-related folds. They formed at the
deformation front and controlled the distribution and deformation of the sediments
during the Pleistocene. The current southern HR started its uplift less than 0.5 Ma.
A seismic relict in the form of a double BSR is a witness to the evolution of the gas
hydrate system of HR. It confirms the recent uplift of the ridge and consequent
shallowing of the base of the gas hydrate stability zone (GHSZ). Further detailed
studies of the stratigraphy reveal stratigraphic controls on the fluid flow, which in
turn control the distribution of gas hydrates. Analysis of the amplitude map of the
bottom-simulating reflector (BSR), which is a proxy for the free gas distribution,
shows a relationship between anticlinal features within the older strata (older than
1.6 Ma) and strong amplitude anomalies of the BSR, which confirm previous
observations suggesting a very low permeability for the young slope-basin
sediments and an accumulation of gas within the older sediments underneath. / Graduation date: 2004
|
Page generated in 0.0776 seconds