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Articles 571 - 600 of 1626

Full-Text Articles in Paleontology

Geobiology: Evidence For Early Life On Earth And The Search For Life On Other Planets, Sherry L. Cady, Nora Noffke Jan 2009

Geobiology: Evidence For Early Life On Earth And The Search For Life On Other Planets, Sherry L. Cady, Nora Noffke

OES Faculty Publications

Extensive research efforts in the subdisciplinary field of geobiology have focused on the interactions between Earth and life through time. As a consequence, gaps in our knowledge of Earth’s history are closing, and the search for life beyond Earth is expanding. A few examples of geobiology studies designed to advance our understanding of life on early Earth and to improve the chances of finding life on other planets are provided to highlight recent developments and research areas that are on the verge of new discoveries.


On The Interpretation Of Caribbean Paleo-Temperature Reconstructions During The Younger Dryas, Xiuquan Wan, Ping Chang, R. Saravanan, Rong Zhang, Matthew W. Schmidt Jan 2009

On The Interpretation Of Caribbean Paleo-Temperature Reconstructions During The Younger Dryas, Xiuquan Wan, Ping Chang, R. Saravanan, Rong Zhang, Matthew W. Schmidt

OES Faculty Publications

A conundrum exists regarding whether the sea-surface temperatures decreased or increased over the southern Caribbean and the western Tropical Atlantic region during the Younger Dryas when the North Atlantic cooled substantially and the Atlantic thermohaline circulation was weakened significantly. Despite the proximity of core locations, some proxy reconstructions record a surface cooling, while others indicate a warming. We suggest that this seemingly paradoxical finding may, at least partially, be attributed to the competing physical processes that result in opposing signs of temperature change in the region in response to weakened North Atlantic meridional overturning circulation. Our coupled ocean-atmosphere model experiments …


Agate Fossil Beds National Monument: Geologic Resources Inventory Report, John Graham Jan 2009

Agate Fossil Beds National Monument: Geologic Resources Inventory Report, John Graham

United States National Park Service: Publications

This report accompanies the digital geologic map for Agate Fossil Beds National Monument in Nebraska, which the Geologic Resources Division produced in collaboration with its partners. It contains information relevant to resource management and scientific research. This document incorporates preexisting geologic information and does not include new data or additional fieldwork.

Formerly a working ranch in sparsely populated northwestern Nebraska, Agate Fossil Beds National Monument is one of the most important paleontological sites in the world for studying Miocene-age mammals and the evolving Miocene world which existed around 20 million years ago. The main bonebeds at Carnegie Hill and University …


Eastern Nebraska Water Resources Assessment (Enwra): Introduction To A Hydrogeological Study, Dana Divine, R. Matthew Joeckel, Jesse T. Korus, P.R. Hanson, Sue Olafsen Lackey Jan 2009

Eastern Nebraska Water Resources Assessment (Enwra): Introduction To A Hydrogeological Study, Dana Divine, R. Matthew Joeckel, Jesse T. Korus, P.R. Hanson, Sue Olafsen Lackey

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Digital Reconstruction Of A Ceratopsid Pes, Ken Conrad Noriega Jan 2009

Digital Reconstruction Of A Ceratopsid Pes, Ken Conrad Noriega

Theses Digitization Project

A complete and fully articulated right pes of a centrosaurine ceratopsid from the Dinossaur Park Formation of Alberta, Canada provides important information regarding the structure and function of the pelvic limb in this group. A reconstructed centrosaurine foot with all data coming directly from actual specimens could be accurately modeled in three-dimensional morphospace and provide the basis of a digital atlas of the elements.


Evolution Of The Cretaceous Calcareous Nanofossil Genus Eiffellithus And Its Biostratigraphic Significance, Jamie L. Shamrock, David K. Watkins Jan 2009

Evolution Of The Cretaceous Calcareous Nanofossil Genus Eiffellithus And Its Biostratigraphic Significance, Jamie L. Shamrock, David K. Watkins

Department of Earth and Atmospheric Sciences: Faculty Publications

The calcareous nanofossil genus Eiffellithus is an important taxon of mid- to Upper Cretaceous marine sediments in biostratigraphy and paleoceanography. The definition of species within Eiffellithus have been both broadly interpreted and variably applied by nanofossil workers. This is particularly true for the Eiffellithus eximius plexus. While the taxonomy of mid-Cretaceous Eiffellithus species has recently been well-defined, the remaining 35 m.y. history of the genus has not been closely examined. Our investigation of Cenomanian to Maastrichtian sediments from the Western Interior Seaway, Gulf of Mexico, and Western Atlantic gives rise to six new species of Eiffellithus that can be reliably …


Pilot Study: The Nature And Thickness Of The Unsaturated Zone And Delineation Of Confined Aquifers, Sue Olafsen Lackey, Les Howard Jan 2009

Pilot Study: The Nature And Thickness Of The Unsaturated Zone And Delineation Of Confined Aquifers, Sue Olafsen Lackey, Les Howard

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Nebraska Statewide Groundwater-Level Monitoring Report 2009, Jesse T. Korus Dr., Mark E. Burbach Jan 2009

Nebraska Statewide Groundwater-Level Monitoring Report 2009, Jesse T. Korus Dr., Mark E. Burbach

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


The Influence Of Fallback Foods On Great Ape Tooth Enamel, Paul J. Constantino, Peter W. Lucas, James J.-W. Lee, Brian R. Lawn Jan 2009

The Influence Of Fallback Foods On Great Ape Tooth Enamel, Paul J. Constantino, Peter W. Lucas, James J.-W. Lee, Brian R. Lawn

Biological Sciences Faculty Research

Lucas and colleagues recently proposed a model based on fracture and deformation concepts to describe how mammalian tooth enamel may be adapted to the mechanical demands of diet (Lucas et al.: Bioessays 30[2008] 374-385). Here we review the applicability of that model by examining existing data on the food mechanical properties and enamel morphology of great apes (Pan, Pongo, and Gorilla). Particular attention is paid to whether the consumption of fallback foods is likely to play a key role in influencing great ape enamel morphology. Our results suggest that this is indeed the case. We also consider the implications of …


Mechanical Properties Of Plant Underground Storage Organs And Implications For Dietary Models Of Early Hominins, Nathaniel J. Dominy, Erin R. Vogel, Justin D. Yeakel, Paul J. Constantino, Peter W. Lucas Jul 2008

Mechanical Properties Of Plant Underground Storage Organs And Implications For Dietary Models Of Early Hominins, Nathaniel J. Dominy, Erin R. Vogel, Justin D. Yeakel, Paul J. Constantino, Peter W. Lucas

Biological Sciences Faculty Research

The diet of early human ancestors has received renewed theoretical interest since the discovery of elevated d13C values in the enamel of Australopithecus africanus and Paranthropus robustus. As a result, the hominin diet is hypothesized to have included C4 grass or the tissues of animals which themselves consumed C4 grass. On mechanical grounds, such a diet is incompatible with the dental morphology and dental microwear of early hominins. Most inferences, particularly for Paranthropus, favor a diet of hard or mechanically resistant foods. This discrepancy has invigorated the longstanding hypothesis that hominins consumed plant underground storage organs (USOs). Plant USOs are …


An Ordovician Global Reference Section Recently Selected In Oklahoma, Daniel Goldman, Stephen A. Leslie, Stig M. Bergström, Jaak Nõlvak, Seth A. Young, Stanley C. Finney Apr 2008

An Ordovician Global Reference Section Recently Selected In Oklahoma, Daniel Goldman, Stephen A. Leslie, Stig M. Bergström, Jaak Nõlvak, Seth A. Young, Stanley C. Finney

Department of Earth, Environment and Sustainability Faculty Publications

Ordovician fossil faunas are characterized by a marked biogeographic differentiation that results in a minimal similarity between most North American faunas and those of major Ordovician areas elsewhere in the world. This provincial distribution of most fossils has led to establishment of different schemes of fossil-based regional stages in, for instance, North America, Baltoscandia, China, and the British Isles.

Because these chrono-stratigraphic units have been largely based on shelly fossils with distributions restricted to a particular region, it has been impossible in most cases to establish a precise international correlation of these regional stages. Furthermore, some general terms, such as …


Comparative Osteohistology Of Hyperelongate Neural Spines In Basal Synapsids (Vertebrata, Amniota): Growth And Mechanical Considerations, Adam Keith Huttenlocker Jan 2008

Comparative Osteohistology Of Hyperelongate Neural Spines In Basal Synapsids (Vertebrata, Amniota): Growth And Mechanical Considerations, Adam Keith Huttenlocker

Theses Digitization Project

Basal synapsids comprise one of the best represented groups of early tetrapods and demonstrate a classic example of a macroevolutionary transition. The basal synapsid fossil record is of significant interest to paleontolists because it presents an excellent opportunity for studying the evolution of vertebrate morphology. In the present study, neural spine osteohistology is further examined across a broad range of basal synapsid genera with hyperlongate neural spines. Due to the limited availability of specimens and the comparative approach required for destructive analysis, the present study is divided into two major comparative investigations: analysis of hyperlongate neural spine in (1) Spenacodontidae …


The Dynamic Evolutionary History Of The Bananaquit (Coereba Flaveola) In The Caribbean Revealed By A Multigene Analysis, Eva Bellemain, Eldredge Bermingham, Robert Ricklefs Jan 2008

The Dynamic Evolutionary History Of The Bananaquit (Coereba Flaveola) In The Caribbean Revealed By A Multigene Analysis, Eva Bellemain, Eldredge Bermingham, Robert Ricklefs

Biology Department Faculty Works

BackgroundThe bananaquit (Coereba flaveola) is a small nectivorous and frugivorous emberizine bird (order Passeriformes) that is an abundant resident throughout the Caribbean region. We used multi-gene analyses to investigate the evolutionary history of this species throughout its distribution in the West Indies and in South and Middle America. We sequenced six mitochondrial genes (3744 base pairs) and three nuclear genes (2049 base pairs) for forty-four bananaquits and three outgroup species. We infer the ancestral area of the present-day bananaquit populations, report on the species' phylogenetic, biogeographic and evolutionary history, and propose scenarios for its diversification and range expansion.ResultsPhylogenetic concordance between …


Arctic Perennial Ice Cover Over The Last 14 Million Years, Dennis A. Darby Jan 2008

Arctic Perennial Ice Cover Over The Last 14 Million Years, Dennis A. Darby

OES Faculty Publications

Knowledge of the long-term history of the perennial ice is an important issue that has eluded study because the Cenozoic core material needed has been unavailable until the recent Arctic Coring Expedition (ACEX). Detrital Fe oxide mineral grains analyzed by microprobe from the last 14 Ma (164 m) of the ACEX composite core on the Lomonosov Ridge were matched to circum-Arctic sources with the same mineral and 12-element composition. These precise source determinations and estimates of drift rates were used to determine that these sand grains could not be rafted to the ACEX core site in less than a year. …


Turbulent Lifestyle: Microbial Mats On Earth’S Sandy Beaches—Today And 3 Billion Years Ago, Nora Noffke Jan 2008

Turbulent Lifestyle: Microbial Mats On Earth’S Sandy Beaches—Today And 3 Billion Years Ago, Nora Noffke

OES Faculty Publications

Archean Earth history is very difficult to reconstruct. Until recently, only bacterial cells preserved in chert, microborings, and stromatolites provided the few clues to ancient life. Now, siliciclastic “microbially induced sedimentary structures” (MISS) are adding to our knowledge of both past life and paleoenvironments. MISS rise from the interaction of photoautotrophic microbial mats with physical sediment dynamics in siliciclastic, shallow-marine settings. Archean MISS can be understood through observations of living microbial mats and modern biotic-physical sedimentary processes. Such geobiological studies are key to the interpretation of the early evolution of prokaryotes. For example, the 2.9 Ga Pongola Supergroup, South Africa, …


Historic Resource Study: Agate Fossil Beds National Monument, Gail Evans-Hatch Jan 2008

Historic Resource Study: Agate Fossil Beds National Monument, Gail Evans-Hatch

United States National Park Service: Publications

As steward of many of the United States' most important cultural and natural resources, the National Park Service (NPS) is required to create background documents along with specific plans aimed at managing and protecting these resources for the enjoyment of present and future generations. An important aspect of managing cultural landscapes requires knowing the past of those landscapes. A historic resource study (HRS) project involves researching and presenting the history of a park. A HRS also attempts to identify and evaluate the importance of all cultural resources within that park. Researching and presenting the broader historical context of a park …


The Global Stratotype Section And Point (Gssp) For The Base Of The Katian Stage Of The Upper Ordovician Series At Black Knob Ridge, Southeastern Oklahoma, Usa, Daniel Goldman, Stephen A. Leslie, Jaak Nõlvak, Seth Young, Stig M. Bergström, Warren D. Huff Dec 2007

The Global Stratotype Section And Point (Gssp) For The Base Of The Katian Stage Of The Upper Ordovician Series At Black Knob Ridge, Southeastern Oklahoma, Usa, Daniel Goldman, Stephen A. Leslie, Jaak Nõlvak, Seth Young, Stig M. Bergström, Warren D. Huff

Department of Earth, Environment and Sustainability Faculty Publications

The International Subcomission on Ordovician Stratigraphy (ISOS) of the International Commission on Stratigraphy (ICS) recently defined the base of the global Upper Ordovician Series to be at the first appearance datum (FAD) of the graptolite species Nemagraptus gracilis in the Fågelsång GSSP in southern Sweden. This designation recognized the tremendous utility for global correlation of the first appearance of a cosmopolitan taxon that occurs within a consistent succession of other first appearance datums (e.g., Finney and Bergström, 1986; Bergström et al., 2000). Current efforts by the ISOS have focused on subdividing the Upper Ordovician into three stages and choosing appropriate …


Pleistocene Peccaries From Guy Wilson Cave, Sullivan County, Tennessee., April Season Nye Aug 2007

Pleistocene Peccaries From Guy Wilson Cave, Sullivan County, Tennessee., April Season Nye

Electronic Theses and Dissertations

Descriptive and taphonomic analyses of undescribed Pleistocene Tayassuidae from Guy Wilson Cave within the East Tennessee State University and McClung Museum collections revealed a MNI of 16 Platygonus compressus and 2 Mylohyus from left femora and isolated teeth, respectively. Linkage between upper dentition and species identification is suggested by comparing Mylohyus fossilis to M. nasutus from other Pleistocene-aged sites. Long-bone NISP and age profiles show a predominance of Platygonus adults. Tayassuidae upper canines, likely Platygonus, suggest sexual dimorphism. Long bones were analyzed for carnivore damage and utilization revealing light utilization similar to that caused by modern wolves. Long bone …


Identification And Catalog Of Holocene And Late Pleistocene Chiropteran Fossils From Hamilton County, Tn, Ashley Miller Mar 2007

Identification And Catalog Of Holocene And Late Pleistocene Chiropteran Fossils From Hamilton County, Tn, Ashley Miller

Honors Theses

Caves play an essential role in our understanding of the Pleistocene Epoch. Caves represent the largest percentage of known North American Pleistocene faunas (Kurten and Anderson, 1980). These unique environments provide stable erosion free conditions that allow fossils to remain preserved for thousands, if not millions, of years (Corgan, 1996; Schubert et al., 2003). The fossil remains found in caves can help paleontologists document biogeographic and evolutionary patterns in a great variety of organisms (Schubert et al., 2003). Many fossils found in cave deposits only date to the Holocene (Schubert et al., 2003). These fossils localities are rarely studied by …


The Evolution Of Zinjanthropus Boisei, Paul J. Constantino, Bernard A. Wood Mar 2007

The Evolution Of Zinjanthropus Boisei, Paul J. Constantino, Bernard A. Wood

Biological Sciences Faculty Research

Many people assume that OH 5, the type specimen of Paranthropus boisei, collected in 1959, was the first evidence of that taxon to be found, but OH 3, recovered in 1955, predated the discovery of OH 5 by four years. Thus, Paranthropus boisei recently celebrated the equivalent of its fiftieth birthday. This review marks that milestone by examining the way our understanding of this taxon has changed during its fifty, or so, year history.


Dundy County Test Hole Logs, Duane A. Eversoll Jan 2007

Dundy County Test Hole Logs, Duane A. Eversoll

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Water Resources And Geologic Field Trip In York And Seward Counties, Nebraska, Michael J. Jess, Mark Burbach Nov 2006

Water Resources And Geologic Field Trip In York And Seward Counties, Nebraska, Michael J. Jess, Mark Burbach

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Correlating Late Pleistocene Deposits On The Coastal Plain Of Virginia With The Glacial-Eustatic Sea-Level Curve, Timothy Wullschleger Scott Apr 2006

Correlating Late Pleistocene Deposits On The Coastal Plain Of Virginia With The Glacial-Eustatic Sea-Level Curve, Timothy Wullschleger Scott

OES Theses and Dissertations

Late Pleistocene sediments mapped along Virginia's southeastern coastal plain record deposition by high-frequency cycles during isotope stages 5 to 1. Correlations between several geologic units both south (S) and east (E) of the Chesapeake Bay have proven difficult due to insufficient dating methods. To improve these regional correlations, two members of the Tabb Formation on Virginia's southside and two formations on the southern Delmarva Peninsula were selected for stratigraphic analyses. Ground penetrating radar provided geologic details in areas where samples were collected for optically stimulated luminescence (OSL) dating. The stratigraphically older units, Sedgefield Member of the Tabb Formation (S) and …


The Earth All Around Us Selected Building Stone In Lincoln, Nebraska, William J. Wayne Mar 2006

The Earth All Around Us Selected Building Stone In Lincoln, Nebraska, William J. Wayne

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Tapeworms Of Elasmobranchs (Part Ii) A Monograph On The Diphyllidea (Platyhelminthes, Cestoda), Gaines Albert Tyler Ii Jan 2006

Tapeworms Of Elasmobranchs (Part Ii) A Monograph On The Diphyllidea (Platyhelminthes, Cestoda), Gaines Albert Tyler Ii

Bulletin of the University of Nebraska State Museum (1924–2023)

The main objective of this monograph was a synthesis of the available knowledge on the diversity, systematics, host associations, and biogeography of the Diphyllidea. A thorough review of the literature resulted in the transfer of Diagonobothrium into Diphyllidea as a genus inquirendum. The genus Yogeshwaria was also transferred to Diphyllidea as a synonym of Echinobothrium. Its only species, E. nagabhushani n. comb., is considered to be a species inquirenda. New collections resulted in the description of a new species of Echinobothrium. Type and/or voucher specimens for 32 of 36 valid diphyllidean species (including the new species) …


Western Caribbean Sea Surface Temperatures During The Late Quaternary, Matthew W. Schmidt, Maryline J. Vautravers, Howard J. Spero Jan 2006

Western Caribbean Sea Surface Temperatures During The Late Quaternary, Matthew W. Schmidt, Maryline J. Vautravers, Howard J. Spero

OES Faculty Publications

[1] Mg/Ca ratios in the planktonic foraminifera Globigerinoides ruber from Colombian Basin core ODP 999A suggest that Caribbean sea surface temperatures ( SSTs) were from 2.1 to 2.7°C colder than the present during the last three glacial maximums. In comparison, faunal derived SSTs ( SIMMAX method) show that August SSTs in the Caribbean varied < 2° over the past 360 kyr, whereas February SSTs varied between 21.0°C and 26.5°C. Changes in the Mg/Ca-SST record contain a strong 23 kyr periodicity, suggesting the Mg/Ca-SST record reflects a warm season weighted SST average rather than an annual mean SST. Combining several dissolution indices, we identify brief periods of decreased carbonate preservation in our record and show that MIS 11 stands out as the most intensive dissolution cycle in the Caribbean over the last 460 kyr. Comparison of Caribbean SST change with a similar estimate of tropical SST variability in the western Pacific over the past 360 kyr reveals shifts in the east-west tropical SST gradient that are coeval with glacial-interglacial climate change and consistent both with a southward migration of the glacial ITCZ and with a glacial El Niño-like mode of tropical circulation.


Groundwater-Level Changes In Nebraska, Spring 2000 To Spring 2006/ Density Of Registered Irrigation Wells In Nebraska August 2005, Conservation Survey Division Jan 2006

Groundwater-Level Changes In Nebraska, Spring 2000 To Spring 2006/ Density Of Registered Irrigation Wells In Nebraska August 2005, Conservation Survey Division

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Plant Paleoecology Of The Late Devonian Red Hill Locality, North-Central Pennsylvania, An Archaeopteris-Dominated Wetland Plant Community And Early Tetrapod Site., Walter L. Cressler Iii Jan 2006

Plant Paleoecology Of The Late Devonian Red Hill Locality, North-Central Pennsylvania, An Archaeopteris-Dominated Wetland Plant Community And Early Tetrapod Site., Walter L. Cressler Iii

Earth & Space Sciences Faculty Publications

The Late Devonian Red Hill locality in north-central Pennsylvania contains an Archaeopteris-dominated plant fossil assemblage, a diverse fossil fauna, and an extensive sedimentary sequence ideal for investigating the landscapes and biotic associations of the earliest forest ecosystems. Sedimentological analysis of the main plantfossil bearing layer at Red Hill indicates that it was a fl ood-plain pond. A seasonal wet-and-dry climate is indicated by well-developed paleovertisols. The presence of charcoal interspersed with plant fossils indicates that fi res occurred in this landscape.Fires appear to have primarily affected the fern Rhacophyton. The specifi city of the fires, the distribution profi …


Spatial Distributions Of Perchloroethylene Reactive Transport Parameters In The Borden Aquifer, Richelle M. Allen-King, Dana Divine, Michel J. L. Robin, J. Richard Alldredge, David R. Gaylord Jan 2006

Spatial Distributions Of Perchloroethylene Reactive Transport Parameters In The Borden Aquifer, Richelle M. Allen-King, Dana Divine, Michel J. L. Robin, J. Richard Alldredge, David R. Gaylord

Conservation and Survey Division: Faculty and Staff Publications

We determined the descriptive statistical and spatial geostatistical properties of the perchloroethene ln Kd and the ln k of a 1.5 m thick by 10 m horizontal transect of the Borden aquifer near the location of the Stanford-Waterloo (SW) tracer experiment. The ln Kd distribution is not normal and is right skewed because of a few high values that occur localized in two regions of the transect. In contrast, the ln k data can be characterized by a normal distribution. A linear regression of ln Kd on ln k yields a statistically significant positive correlation, also shown …


From Soft Tissue To Homing Pigeons (Faith & Science Update), John T. Baldwin Jan 2006

From Soft Tissue To Homing Pigeons (Faith & Science Update), John T. Baldwin

Perspective Digest

No abstract provided.