Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 18 of 18

Full-Text Articles in Physical Sciences and Mathematics

San Andreas Structural Interpretation: Merging Geophysical And Geological Data At Safod And Vicinity, Rebekah E. Wood, James P. Evans, Peter E. Malin Nov 2010

San Andreas Structural Interpretation: Merging Geophysical And Geological Data At Safod And Vicinity, Rebekah E. Wood, James P. Evans, Peter E. Malin

Rebekah Wood

No abstract provided.


Background Fluorescence In Groundwater From A Tropical Karst Island Aquifer, Michelle Hoffman Sep 2010

Background Fluorescence In Groundwater From A Tropical Karst Island Aquifer, Michelle Hoffman

Michelle Hoffman

Background levels of four fluorescent compounds were monitored biweekly at thirteen sampling sites on Guam, consisting of subtidal and intertidal springs, dissolution fractures, and internal upland contact spring discharge, over a 13-month period from 2006 to 2007. Samples were compared to local precipitation and to seawater samples from four nearby reef flats. The data revealed that the concentrations of optical brighteners were consistently two orders of magnitude greater than either sodium fluorescein or rhodamine WT, while Eosine Y was rarely detected. Background levels in seawater, by comparison, accounted for 25% or more of the fluorescent compounds detected at the thirteen …


Late Quaternary Distribution And Biogeography Of The Southern Lake Eyre Basin (Sleb) Megafauna, South Australia, Steve Webb Aug 2010

Late Quaternary Distribution And Biogeography Of The Southern Lake Eyre Basin (Sleb) Megafauna, South Australia, Steve Webb

Steve Webb

Understanding the population demography, species distribution and biogeography of Australia’s megafauna is essential for understanding their extinction. This process is only just beginning, and this article discusses these aspects while concentrating on a particular region; the southern Lake Eyre Basin (SLEB). It is also the first detailed description of the distribution of megafauna across that region of central Australia. The data are based on an extensive longitudinal study of 41 palaeontological sites spread across 250 000km2. Megafauna adaptation and response to extensive environmental change during the late Quaternary is reflected in the composition and distribution of 21 megafauna species found …


Evolution Of The Kangmar Dome, Southern Tibet: Structural, Petrologic, And Thermochronologic Constraints, Jeffrey Lee, Bradley Hacker, William Dinklage, Yu Wang, Phillip Gans, Andrew Calvert, Ann Blythe, William Mcclelland Jul 2010

Evolution Of The Kangmar Dome, Southern Tibet: Structural, Petrologic, And Thermochronologic Constraints, Jeffrey Lee, Bradley Hacker, William Dinklage, Yu Wang, Phillip Gans, Andrew Calvert, Ann Blythe, William Mcclelland

Ann Blythe

Structural, thermobarometric, and thermochronologic investigations of the Kangmar Dome, southern Tibet, suggest that both extensional and contractional deformational histories are preserved within the dome. The dome is cored by an orthogneiss which is mantled by staurolite + kyanite zone metasedimentary rocks; metamorphic grade dies out up section and is defined by a series of concentric kyanite-in, staurolite-in, garnet-in, and chloritoid-in isograds. Three major deformational events, two older penetrative events and a younger doming event, are preserved. The oldest event, D1, resulted in approximately E-W trending tight to isoclinal folds of bedding with an associated moderately to steeply north dipping axial …


Central New York Varve Chronology: A Suggestion For Quaternary Geologists, Thomas Bradley Walker Mar 2010

Central New York Varve Chronology: A Suggestion For Quaternary Geologists, Thomas Bradley Walker

Thomas Bradley Walker

Work done to build a chronology of deglaciation using varves has been the focus of a number of researchers in New England for many years. The locations employed to build their timeline have been quite useful to date. However, New England is not the only place in the Northeast conducive to studying the last deglaciation of North America. The discovery of a set of ice proximal varves in an ancient glacial lake, now a swamp, in Oswego County, central New York, has shown that some locations outside of New England would be suitable for similar studies. The land having been …


Cenozoic Mass Extinctions In The Deep Sea; What Disturbs The Largest Habitat On Earth?, Ellen Thomas Feb 2010

Cenozoic Mass Extinctions In The Deep Sea; What Disturbs The Largest Habitat On Earth?, Ellen Thomas

Ellen Thomas

No abstract provided.


Assessing The Impact Of Geosciences Laboratories On Student Learning: Who Benefits From Introductory Labs, Karl Nelson, Kristin Huysken, Zoran Kilibarda Jan 2010

Assessing The Impact Of Geosciences Laboratories On Student Learning: Who Benefits From Introductory Labs, Karl Nelson, Kristin Huysken, Zoran Kilibarda

Zoran Kilibarda

Laboratories serve as an integral part of geoscience education at most colleges and universities. While anecdotal evidence supports the beneficial impact of laboratories on science class learning, little quantitative research backs this statement. This study compared classroom data from students who completed a geoscience laboratory in conjunction with an introductory-level lecture-based course to those who completed the lecture course only. Laboratory-enrolled students performed better in the lecture class, resulting in an increase of 5.5% in their final class score. Even after controlling for GPA, laboratory enrollment accounted for a statistically significant proportion of the variance. Nontraditional students (age 25 and …


Diurnal Patterns Of Blowing Sand, John E. Stout Jan 2010

Diurnal Patterns Of Blowing Sand, John E. Stout

John E. Stout

The diurnal pattern of blowing sand results from a complex process that involves an interaction between solar heating, thermal instability, atmospheric turbulence, wind strength, and surface threshold conditions. During the day, solar heating produces thermal instability, which enhances the convective mixing of high momentum winds from the upper levels of the atmosphere to the surface layer. The sun also dries the sand surface so that the critical threshold is as low as possible. Thus, in the afternoon, the combination of strong turbulent winds and a low surface threshold increases the likelihood that winds may intermittently exceed the critical threshold of …


Re-Interpreting Great Lakes Shorelines As Components Of Wave-Influenced Deltas: An Example From The Portage River, Lake Erie, Ohio, James E. Evans Jan 2010

Re-Interpreting Great Lakes Shorelines As Components Of Wave-Influenced Deltas: An Example From The Portage River, Lake Erie, Ohio, James E. Evans

James E. Evans

No abstract provided.


Quaternary Geology And Geochronology Of The Uppermost Arkansas Valley, Colorado- Glaciers, Ice Dams, Landslides, And Floods, James P. Mccalpin Jan 2010

Quaternary Geology And Geochronology Of The Uppermost Arkansas Valley, Colorado- Glaciers, Ice Dams, Landslides, And Floods, James P. Mccalpin

James P. McCalpin

This field trip to the uppermost Arkansas Valley of central Colorado is based mainly on work performed since 2008, in an area with a long history of bedrock mapping by renowned geologists of the U.S. Geological Survey beginning in the 1880s (e.g. Emmons, 1886). The Quaternary features of the region were first described by Capps in 1909. Despite over 100 years of intermittent geologic studies here, there were still new discoveries to be made in the past few years. Day 1 of the trip emphasizes landslides (in the morning) and glacial deposits (in the afternoon). The “take-home messages” of the …


Collaborative Research: Graptolite Biogeography, Paleo-Gis, And Evolutionary Dynamics Of Early Paleozoic Zooplankton, Daniel Goldman Dec 2009

Collaborative Research: Graptolite Biogeography, Paleo-Gis, And Evolutionary Dynamics Of Early Paleozoic Zooplankton, Daniel Goldman

Daniel Goldman

Funding Agency: National Service Foundation Investigators: Dr. Goldman, SY. Wu Amount: $255,326.00 Number of years: 4 years


Deformation Of Continental Crust Along A Transform Boundary, Coast Mountains, British Columbia, Scott Bogue, Margaret Rusmore, Karen Dodson, Kenneth Farley, Glenn Woodsworth Dec 2009

Deformation Of Continental Crust Along A Transform Boundary, Coast Mountains, British Columbia, Scott Bogue, Margaret Rusmore, Karen Dodson, Kenneth Farley, Glenn Woodsworth

Scott Bogue

New structural, paleomagnetic, and apatite (U-Th)/He results from the continental margin inboard of the Queen Charlotte fault (∼54°N) delineate patterns of brittle faulting linked to transform development since ∼50 Ma. In the core of the orogen, ∼250 km from the transform, north striking, dip-slip brittle faults and vertical axis rotation of large crustal domains occurred after ∼50 Ma and before intrusion of mafic dikes at 20 Ma. By 20 Ma, dextral faulting was active in the core of the orogen, but extension had migrated toward the transform, continuing there until <9 Ma. Local tilting in the core of the orogen …


Faculty Spotlight: Mark Sutherland, Mark Sutherland Dec 2009

Faculty Spotlight: Mark Sutherland, Mark Sutherland

Mark Sutherland

Interview with Mark J. Sutherland about his earth science teaching career at College of DuPage.


Very Rapid Geomagnetic Field Change Recorded By The Partial Remagnetization Of A Lava Flow, Scott Bogue, Jonathan Glen Dec 2009

Very Rapid Geomagnetic Field Change Recorded By The Partial Remagnetization Of A Lava Flow, Scott Bogue, Jonathan Glen

Scott Bogue

A new paleomagnetic result from a lava flow with a distinctive, two-part remanence reinforces the controversial hypothesis that geomagnetic change during a polarity reversal can be much faster than normal. The 3.9-m-thick lava (“Flow 20”) is exposed in the Sheep Creek Range (north central Nevada) and was erupted during a reverse-to-normal (R-N) geomagnetic polarity switch at 15.6 Ma. Flow 20 began to acquire a primary thermoremanence while the field was pointing east and down but was soon buried, reheated, and partially-remagnetized in a north-down direction by the 8.2-m-thick flow that succeeded it. A simple conductive cooling calculation shows that the …


Fabric Development In Cm-Scale Shear Zones In Ultramafic Rocks, Red Hills, New Zealand, Caroline Webber, Julie Newman, Caleb Holyoke, Timothy Little, Basil Tikoff Dec 2009

Fabric Development In Cm-Scale Shear Zones In Ultramafic Rocks, Red Hills, New Zealand, Caroline Webber, Julie Newman, Caleb Holyoke, Timothy Little, Basil Tikoff

Caleb Holyoke

No abstract provided.


Accurate Differential Stress Measurement Using The Molten Salt Cell And Solid Salt Assemblies In The Griggs Apparatus With Applications To Strength, Piezometers And Rheology, Caleb Holyoke, Andreas Kronenberg Dec 2009

Accurate Differential Stress Measurement Using The Molten Salt Cell And Solid Salt Assemblies In The Griggs Apparatus With Applications To Strength, Piezometers And Rheology, Caleb Holyoke, Andreas Kronenberg

Caleb Holyoke

No abstract provided.


Deformation Of Single Crystal Sample Using D-Dia Apparatus Coupled With Synchrotron X-Rays: In-Situ Stress And Strain Measurements At High Pressure And Temperature, Jennifer Girard, Jiuhua Chen, Paul Raterron, Caleb Holyoke Dec 2009

Deformation Of Single Crystal Sample Using D-Dia Apparatus Coupled With Synchrotron X-Rays: In-Situ Stress And Strain Measurements At High Pressure And Temperature, Jennifer Girard, Jiuhua Chen, Paul Raterron, Caleb Holyoke

Caleb Holyoke

No abstract provided.


Forward Modeling Synsedimentary Deformation Associated With A Prograding Steep-Sloped Carbonate Margin, Phillip G. Resor Dec 2009

Forward Modeling Synsedimentary Deformation Associated With A Prograding Steep-Sloped Carbonate Margin, Phillip G. Resor

Phillip G Resor

Differential compaction associated with prograding and aggrading steep-rimmed carbonate margins leads to penecontemporaneous and post- depositional modifications of stratal geometries and tensile and shear stress concentrations that result in brittle deformation. In an effort to investigate controls on these deformation processes, we employ a step-wise gravity loaded elastic model that captures pre-failure displacement and stress field patterns for a depositional geometry based on the Permian Capitan depositional system, Guadalupe Mountains, West Texas and New Mexico, USA. We consider four model geometries with varying progradation to aggradation (P/A) ratio, from strongly prograding (P/A=10) to strongly aggrading (P/A=0.1). The strongly prograding case …