Physical Sciences and Mathematics Commons^™

Geol 112: Hazards, Risks Of Earthquakes And Volcanoes Textbook Alternatives, Donald Reed

Donald Reed

Poster summarizing cost saving textbook alternatives for GEOL 112: Hazards, Risks of Earthquakes and Volcanoes.

Topographic Control Of Asynchronous Glacial Advances: A Case Study From Annapurna, Nepal, B. Pratt-Sitaula, D. W. Burbank, A. M. Heimsath, Neil Humphrey, M. Oskin, J. Putkonen

Neil Humphrey

Differences in the timing of glacial advances, which are commonly attributed to climatic changes, can be due to variations in valley topography. Cosmogenic Be-10 dates from 24 glacial moraine boulders in 5 valleys define two age populations, late-glacial and early Holocene. Moraine ages correlate with paleoglacier valley hypsometries. Moraines in valleys with lower maximum altitudes date to the late-glacial, whereas those in valleys with higher maximum altitudes are early Holocene. Two valleys with similar equilibrium-line altitudes (ELAs), but contrasting ages, are aspect, such that spatial differences in climate can be excluded. A glacial mass-balance cellular automata model of these two …

Geology Of The Chester, Ridley, And Crum Watersheds – Violent Past, Tranquil Present, Walter Cressler

Walt Cressler

No abstract provided.

The Quasi-Static Deformation, Failure, And Fracture Behavior Of Titanium Alloy Gusset Plates Containing Bolt Holes, Therese Hurtuk, Craig Menzemer, Anil Patnaik, Tirumalai Srivatsan, Kannan Manigandan, T. Quick

Craig Menzemer

In this article, the influence of bolt holes, specifically their number and layout on strength, deformation, and final fracture behavior of titanium alloy gusset plates under the influence of an external load is presented and discussed. Several plates having differences in both the number and layout of the bolt holes were precision machined and then deformed under quasi-static loading. The specific influence of number of bolt holes and their layout on maximum load-carrying capability and even fracture load was determined. The conjoint influence of bolt number, bolt layout pattern, nature of loading, contribution from local stress concentration, and intrinsic microstructural …

The Sedimentary Flux Of Dissolved Rare Earth Elements To The Ocean, April Abbott, Brian Haley, James Mcmanus, Clare Reimers

James McManus

We determined pore fluid rare earth element (REE) concentrations in near-surface sediments retrieved from the continental margin off Oregon and California (USA). These sites represent shelf-to-slope settings, which lie above, within, and below the oxygen minimum zone of the Northeast Pacific. The sediments are characterized by varying degrees of net iron reduction, with pore fluids from the shelf sites being generally ferruginous, and the slope sediments having less-pronounced iron reduction zones that originate deeper in the sediment package. REE concentrations show maxima in shallow (upper 2–10 cm) subsurface pore fluids across all sites with concentrations that rise more than two …

The Quasi-Static Deformation, Failure, And Fracture Behavior Of Titanium Alloy Gusset Plates Containing Bolt Holes, Therese Hurtuk, Craig Menzemer, Anil Patnaik, Tirumalai Srivatsan, Kannan Manigandan, T. Quick

Anil Patnaik

In this article, the influence of bolt holes, specifically their number and layout on strength, deformation, and final fracture behavior of titanium alloy gusset plates under the influence of an external load is presented and discussed. Several plates having differences in both the number and layout of the bolt holes were precision machined and then deformed under quasi-static loading. The specific influence of number of bolt holes and their layout on maximum load-carrying capability and even fracture load was determined. The conjoint influence of bolt number, bolt layout pattern, nature of loading, contribution from local stress concentration, and intrinsic microstructural …

Geochronology Of Hemphillian-Blancan Aged Strata, Guanajuato, Mexico, And Implications For Timing Of The Great American Biotic Interchange, Bart Kowallis, John Flynn, Clarita Nunez, Oscar Carranza-Castaneda, Wade Miller, Carl Swisher, Everett Lindsay

Bart J Kowallis

We present new geochronologic magnetostratigraphy, fission-track and 40Ar/39Ar radioisotopic dates, biostratigraphy)bdata constraining the age of three separate sequences and a composite section from Guanajuato, Mexico. Those data make this one of the most complete and precisely age-calibrated sequences in North America spanning the Hemphillian/Blancan North American Land Mammal “Age” (NALMA) boundary interval, and the data further constrain the timing and pattern of the Great American Biotic Interchange (GABI). In total, 196 samples (77 sites) were used to construct the magnetic polarity stratigraphies, with eight fission-track analyses and four new 40Ar/39Ar radioisotopic dates. The sections sampled are possibly latest Miocene to …

Contrasting Silicic Magma Series In Miocene-Pliocene Ash Deposits In The San Miguel De Allende Graben, Guanajuato, Mexico, Eric Christiansen, Bart Kowallis, Aaron Adams, Oscar Carranza-Castaneda, Wade Miller

Bart J Kowallis

The San Miguel de Allende graben, Guanajuato, Mexico, contains numerous rhyolitic volcanic ash beds. Electron microprobe and x-ray fluorescence analyses of glass shards from 14 localities, combined with mineralogic, stratigraphic, radiometric, and paleomagnetic data, allow us to correlate the ash beds (and the intervening sedimentary strata and fossils), understand the timing of volcanism, date the age of extension, and better understand the tectonic and volcanic evolution of central Mexico. Our analyses reveal that at least six separate eruptions of rhyolitic ash occurred during the Late Miocene and Pliocene (5-3 Ma) while the San Miguel Allende basin was subsiding. The fallout …

The Digital Atlas Of Ancient Life: Delivering Information On Paleontology And Biogeography, Jonathan R. Hendricks, Alycia L. Stigall, Bruce S. Lieberman

Jonathan R. Hendricks

No abstract provided.

Preliminary Geophysical Characterization Of The Karst Within A Transverse Glade In The Atlantic Coastal Ridge, Miami-Dade County Florida, Usa, Lee J. Florea, Jeff Ransom, Dallas Hazelton

Lee J Florea, PhD, P.G.

In this paper we present results of two DC Electrical Resistivity Tomography surveys at Deering Estate at Cutler in the Atlantic Coastal Ridge of Miami-Dade County, Florida. This County Natural Area encompasses Deering Glade and hosts one of the largest remaining tropical hardwood-hammock ecosystems in the USA. A canal extension, wetland restoration, and pump station recently constructed at Deering Estate by the South Florida Water Management District is designed to re-hydrate Deering Glade to pre-development conditions thus helping to sustain the hammock ecosystem and reverse trends in salt-water intrusion in this portion of the Biscayne aquifer. For these transects, we …

Neotectonics Of Major Faults Based On Strain Analysis And U-Th Dating Of Syntectonic Calcite, R. Weinberger, P. Nuriel, John Craddock

John Craddock

No abstract provided.

Stable Isotope Studies Of Paleoenvironment And Paleoclimate From Afar, Ethiopia, Zelalem K. Bedaso

Zelalem Bedaso

ABSTRACT The sedimentary deposits of the Hadar Formation at Dikika and the Mount Galili Formation at Galili preserve a wealth of paleoenvironmental and paleoclimatic records spanning the last 5.29 Ma. Stable carbon and oxygen isotopic compositions of herbivore tooth enamel were analyzed for more than 600 specimens of 15 different taxa from 10 stratigraphic intervals. The application of carbon and oxygen isotopes here aims principally at reconstructing shifts in the relative abundance of C4 grasses, and its implications for climate indicators including temperature, aridity, and seasonality. The full range of δ13Cenamel values throughout the Plio-Pleistocene signifies a wide range of …

Glowing Seashells: Diversity Of Fossilized Coloration Patterns On Coral Reef-Associated Cone Snail (Gastropoda: Conidae) Shells From The Neogene Of The Dominican Republic, Jonathan R. Hendricks

Jonathan R. Hendricks

The biology of modern Conidae (cone snails)—which includes the hyperdiverse genus Conus—has been intensively studied, but the fossil record of the clade remains poorly understood, particularly within an evolutionary framework. Here, ultraviolet light is used to reveal and characterize the original shell coloration patterns of 28 species of cone snails from three Neogene coral reef-associated deposits from the Cibao Valley, northern Dominican Republic. These fossils come from the upper Miocene Cercado Fm. and lower Pliocene Gurabo Fm., and range in age from about 6.6-4.8 Ma. Comparison of the revealed coloration patterns with those of extant species allow the taxa to …

Late Pleistocene Glacial History And Magnetic Chronostratigraphy, Western Adirondack Borderland, New York, Donald Pair

Donald L. Pair

New lines of evidence from the western Adirondack borderland have been employed to assess the style of deglaciation and reconstruct the nature and timing of associated proglacial lacustrine and marine (Champlain Sea) events. Contrasting styles of deglaciation, controlled primarily by water depth, resulted in landfast ice withdrawing gradually on the northern slope of the Adirondacks while actively calving ice, retreating rapidly in the deep water of Lake Iroquois, quickly evacuated the western St. Lawrence Lowland of ice. The extent of ice retreat from the western St. Lawrence Lowland during the life of Lake Iroquois has been estimated on the basis …

Communicating The Science Of Igcp 591 To The Public, Lewandowski J. Katherine

Katherine J. Lewandowski

Selling the broader impacts of science to funding agencies has become a necessity in a time when competition for grant money is high. While involving students in research is still important for maintaining a pipeline of trained scientists, the bar has been raised and it is increasingly incumbent on us to communicate to the public what is so important about our work. To be competitive in the search for funds, there must be a plan for the science funded to be disseminated to the public. The education and outreach plan for IGCP 591 attempts to appeal to this broader audience …

Validation Of Recent Shear Wave Velocity Models In The United States With Full-Wave Simulation, Haiying Gao, Yang Shen

Haiying Gao

Interpretations of dynamic processes and the thermal and chemical structure of the Earth depend on the accuracy of Earth models. With the growing number of velocity models constructed with different tomographic methods and seismic data sets, there is an increasing need for a systematic way to validate model accuracy and resolution. This study selects five shear wave velocity models in the U.S. and simulates full wave propagation within the 3-D structures. Surface-wave signals extracted from ambient seismic noise and regional earthquakes are compared with synthetic waveforms at multiple-frequency bands. Phase delays and cross-correlation coefficients between observed and synthetic waveforms allow …

Longitudinal Profile And Sediment Mobility As Geomorphic Tools To Interpret The History Of A Fluviokarst Stream System, John Woodside, Eric Peterson, Toby Dogwiler

Eric Wade Peterson

The complex drainage systems within karst settings can result in atypical longitudinal profiles. Features, such as cave entrances, can be expressed as anomalous ‘bumps’ in the longitudinal profile of a stream if downcutting has continued upstream of the area in which the water is pirated to the subsurface. Horn Hollow, a fluviokarst valley located in Carter Caves State Park Resort in northeastern Kentucky, was examined for these types of features. The objectives of this study were to determine if sediment mobility can be used as a proxy for anomalous areas along the profile of the valley and if detailed cross-sections …

Three-Dimensional Geologic Model Of The Pecatonica Gas Storage Field, Winnebago County, Illinois, Nicole Kron, David Malone, Eric Peterson

Eric Wade Peterson

Stratigraphy And Porosity Modeling Of Southern Centeral Illinois Chester (Upper Missisippian) Series Sandstones Usng Petrel, Darren Kimple, Eric Peterson, David Malone

Eric Wade Peterson

Identification Of Potential Vertical Gas Migration Pathways Above Gas Storage Reservoirs, Eric Peterson, Lauren Martin, David Malone

Eric Wade Peterson

Rock Strength Along A Fluvial Transect Of The Colorado Plateau - Quantifying A Fundamental Control On Geomorphology, Natalie Bursztyn, Joel Pederson

Natalie Bursztyn

Bedrock strength is a key parameter that influences slope stability, landscape erosion, and fluvial incision. Yet, it is often ignored or indirectly constrained in studies of landscape evolution, as with the K erodibility parameter in stream-power models. Empirical datasets of rock strength suited to address geomorphic questions are rare, in part because of the difficulty in measuring those rocks at Earth's surface that are heterolithic, weak, or poorly exposed. Here we present a large dataset of measured bedrock strength organized by rock units exposed along the length of the trunk Green–Colorado River through the iconic Colorado Plateau of the western …