Life Sciences Commons^™

Excavations At Natural Trap Cave, Larry D. Martin, B. Miles Gilbert

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

Among the more important questions addressed by students of earth history are those that relate to climatic change. This is especially true of change that has taken place during the last two million years of the "Ice Age." It is not an accident that a great deal of effort has been directed towards the Late Pleistocene, and our knowledge of Late Pleistocene environmental parameters has increased markedly in the past few years. However, our knowledge of these changes is still incomplete, and we still have some uncertainty about the cause and nature of Late Pleistocene climatic change, its possible relationship …

The Classical European Glacial Stages: Correlation With Deep-Sea Sediments, George Kukla

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

Four glacials and three interglacials, recognized by classical Alpine and North-European subdivisions of the Pleistocene, were correlated with continuous oxygen-isotope records from the oceans using loess sections and terraces as a link (Fig. 15). It was found that the Alpine "glacial" stages are represented by sediments formed during both glacial and interglacial climates, that the classical Alpine "interglacial" stages do not represent episodes of interglacial climate but probably intervals of accelerated crustal movements, and that the physical evidence on which the North-European classical subdivision is based is misinterpreted due to lengthy gaps in the record.

It is recommended to discontinue …

Progress On Rock Glacier Research, John F. Shroder Jr., John R. Giardino

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

This report is an account of research progress on rock glaciers of Afghanistan, Colorado, and Utah. Because of the preliminary nature of this work, some speculation is present; nevertheless, we think there is evidence for each major, new point expressed. The main thesis of our work is that rock glaciers are polygenetic and appear to be part of a continuum of similar landforms grading morphologically and, presumably, mechanically from one type to another type.

The End Of The Pleistocene In North America, Larry D. Martin, A. M. Neuner

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

The excavations at Natural Trap Cave have stimulated our interest in the changes that took place some 12,000 to 8,000 years ago that mark the end of the Pleistocene. Of these changes, the extinction that occurred at the end of the Pleistocene in North and South America is near enough in time, and the animals involved are well enough known, to stimulate interest in the causal mechanism. With the possible exception of the extinction of dinosaurs at the end of the Cretaceous, none other has been the subject of more varied and extensive speculation. One of the most attractive hypotheses …

The Origins Of Spring Migratory Staging By Sandhill Cranes And White-Fronted Geese, Roger S. Sharpe

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

A most unusual avian migratory event takes place each spring in the Platte River basin of Nebraska between 98 and 102 degrees longitude (Fig. 1). In suitable habitats throughout this area large concentrations of Sandhill Cranes, Grus canadensis, and White-fronted Geese, Anser albifrons, develop and achieve peak populations in mid to late March. This phenomenon is traditional to the migratory habits of specific populations and occurs during the spring movement from wintering grounds in Texas, New Mexico, and Mexico to breeding grounds far to the north in Canada and Alaska. In both species groups of individuals drift in …

Transactions Of The Nebraska Academy Of Sciences Volume Vi (1978): Table Of Contents

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

Nebraska Academy of Sciences, Officers, Policy Committee .......... ii

Editorial Board, Instructions to Contributors .......... v

Symposium: "The Ice Age- When dd it begin and has it ended"

Cochairmen: John F. Shroder, Jr. and Lloyd G. Tanner

The comparative method in stratigraphy: the beginning and end of an ice age (T. M. Stout) .......... 1

The Plio-Pleistocene: sediments, environments, and geochronology along the Karari Escarpment, East Turkana, Kenya (Vondra, Burggraf, Jr., and White) .......... 19

Chronology of some Late Cenozoic deposits from the central United States and the Ice Ages (J. D. Boellstorff) .......... 35

Progress on rock glacier research …

The Plio-Pleistocene: Sediments, Environments, And Geochronology Along The Karari Escarpment, East Turkana, Kenya, Carl F. Vondra, Daniel R. Burggraf Jr., Howard J. White

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

The sedimentary sequence of East Turkana, Kenya, provides an excellent opportunity to document change contemporary with the Plio-Pleistocene boundary in East Africa. Within exposures along the Karari Ridge, sediments of the Fluvio-lacustrine Koobi Fora Formation record a dramatic change in depositional regime from low to high energy attributable to climate change and/or tectonic activity. The correlation of this abrupt transition with the beginning of the Pleistocene epoch is not without question, but controversy resulting from radiometric dating of volcanic ash units, paleomagnetic zonation, and paleontologic data exists and indicates that resolution of the Plio-Pleistocene boundary at East Turkana will be …

The Middle Missouri Tradition In Retrospect, Warren W. Caldwell

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

The "culture history" of the Missouri trench in North and South Dakota has been phrased in climatological parameters. The life cycle of the Middle Missouri Tradition in particular seems to correlate closely with the Neo-Atlantic eposide, yet the interpretation is speculatory because appropriate climatic data are not available.

The Complexity Of Measuring The Impact Of Possible Climatic Change On Agriculture, R. E. Neild

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

Much geological and paleontological evidence exists of major changes in climate over widespread areas of the world including Nebraska. What is now Nebraska was once warm enough to support flora and fauna found now only in tropical areas. During the last Ice Age the climate of what is now Lincoln was similar to Igvitut at the base of the large glacier covering most of Greenland.

Recent weather fluctuations and consequent variations in essential food (Newman and Pickett, 1974), fuel, and water supplies have prompted speculation that climate is changing toward some former extreme. Massive purchases of grain by the Soviet …

The Comparative Method In Stratigraphy: The Beginning And End Of An Ice Age, Thompson Mylan Stout

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

Glaciation should now be treated as a regularly repetitive process, not as an irregular process through geologic time. If so, the changes in volume of the world ocean (glacio-eustasy) may be expected to account primarily for the major advances and retreats of the sea (the "pulsations" of Grabau) that arc global and characteristic of all continental platforms (cratonic margins). These larger cycles, best termed stages (equivalent to the "megacycles" or "megacyclothems" of Moore, and to the "mesothems" of Ramsbottom), resemble the Quaternary Model, whether comparison is made with sedimentary cycles of the Paleozoic, Mesozoic, or Tertiary. Conversely, the Quaternary may …

Chronology Of Some Late Cenozoic Deposits From The Central United States And The Ice Ages, John Boellstorff

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

The first of four North American Ice Ages commenced about 2.8 m.y. ago, reached a maximum between 2.4 and 2.6 m.y. ago during which continental glaciers invaded southwestern Iowa and southeastern Nebraska, and ended about 2.1 m.y. ago. This first Ice Age may span the Pliocene-Pleistocene boundary herein placed at 2.5 ± 0.1 m.y. The second Ice Age occurred about 1.9 to 1.5 m.y. ago. However, apparently it was not severe enough for glaciers to reach into Nebraska or central Iowa. The third Ice Age occurred between about 1.0 and 0.4 m.y. ago. Glaciers invaded Nebraska and Iowa at least …

The Evidence For Climatic Change From Antarctica?, Robert H. Rutford

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

The stratigraphic record of the Antarctic continent records a history compatible and comparable with that of any of the other continents: a Pre-Cambrian basement truncated by a major erosion surface, a sequence of Paleozoic and Mesozoic sediments, and finally a Cenozoic record dominated by glacial deposits. Two major geologic provinces are recognized: East Antarctica, a typical continental shield or stable platform consisting of older igneous and metamorphic rocks overlain by younger, mainly flat-lying stratified sedimentary and igneous rocks; West Antarctica is composed mainly of younger rocks that are deformed and metamorphosed-abundant intrusive and extrusive rocks are present and volcanic activity …

Climatic Change And The Extinction Of Large Mammals During The Quaternary, C. Bertrand Schultz, John M. Hillerud

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

There is an abundance of soils and paleosols as well as terraces and terrace fills and erosional forms of pediments to aid in working out a precise stratigraphic sequence for the Quaternary animals. The dating and correlation of Quaternary deposits are complex, and we must realize that there were numerous glacial advances and retreats. A continuing reexamination of the relationship of the mammalian faunas to the paleosols, terrace fills, volcanic ashes, and other geologic features must be done in order to provide a proper framework for the interpretation of the mammalian stratigraphic sequences.

The horses and camels, which had so …

Excavation At The Hot Springs Mammoth Site: A Late Pleistocene Animal Trap, Larry D. Agenbroad

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

Construction work on a housing development in southern Hot Springs, South Dakota, during July 1974 exposed teeth, tusks, skulls, and post-cranial elements of mammoth. These were located in a small deposit of sand within the Spearfish Formation, a red shale of Permian-Triassic age.

The deposit was originally a topographic depression. Prior to construction, it stood as a ridge, the sand and gravel armoring the adjacent shale. It is currently a sandy knob left by the construction work.

Initial excavation during 1974 and 1975 (Agenbroad and Jones, 1975) was salvage and exploratory in nature. The abundant faunal remains from such efforts …

Political And Social Implications Of Possible Climatic Changes, Robert D. Miewald

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

There is something rather ludicrous about a learned paper on the political and social implications of the end of the world. Obviously, since we do not have much reliable historical information about this sort of event, the author can only offer some speculations which, however well-informed, are of debatable quality. And the reader, insofar as he or she actually believes in impending disaster, will doubtless be disappointed by the absence of any specific recommendations about how to survive. Yet while this exercise may seem foolish, it is undertaken because of the conviction that it would be even more foolish for …