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

Earth Sciences Commons

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

Articles 1 - 9 of 9

Full-Text Articles in Earth Sciences

Overview Of Radiometric Ages In Three Allochthonous Belts Of Northern Venezuela: Old Ones, New Ones, And Their Impact On Regional Geology, V Sisson, H Lallemant, M Ostos, Ann Blythe, L Snee, P Copeland, J Wright, R Donelick, L Guth Dec 2004

Overview Of Radiometric Ages In Three Allochthonous Belts Of Northern Venezuela: Old Ones, New Ones, And Their Impact On Regional Geology, V Sisson, H Lallemant, M Ostos, Ann Blythe, L Snee, P Copeland, J Wright, R Donelick, L Guth

Ann Blythe

No abstract provided.


Exploring The Persistence Of Sorted Bedforms On The Inner-Shelf Of Wrightsville Beach, North Carolina, Benjamin Gutierez, George Voulgaris, Robert Thieler Dec 2004

Exploring The Persistence Of Sorted Bedforms On The Inner-Shelf Of Wrightsville Beach, North Carolina, Benjamin Gutierez, George Voulgaris, Robert Thieler

George Voulgaris

Geological studies offshore of Wrightsville Beach, North Carolina reveal subtle large-scale regions of coarse sand with gravel and shell hash (widths between 100 and 200 m and negative relief of ∼1 m) that trend obliquely to the coast. It was previously suggested that these regions serve as conduits for sand exchange between the shoreface and inner shelf during storm-associated downwelling. Consequently they were classified as rippled scour depressions. More recently, the role of alongshore flows and self-organization as a result of inhibited settling of fine sand has been discussed. In this study, 45 days of near-bed current measurements were analyzed …


Effect Of Channel Bifurcation On Residual Estuarine Circulation: Winyah Bay, South Carolina, Yong Kim, George Voulgaris Dec 2004

Effect Of Channel Bifurcation On Residual Estuarine Circulation: Winyah Bay, South Carolina, Yong Kim, George Voulgaris

George Voulgaris

The residual circulation pattern of Winyah Bay, the fourth largest estuary on the eastern coast of the US, is examined using stationary and shipborne current measurements during periods of low freshwater discharge. The estuary has a complex morphology with a single channel and narrow banks at the river entrance and the bay mouth, and a bifurcated channel system (main and western channels, respectively) in the middle part that appears to affect the residual circulation. Overall, the upper (single channel morphology) and middle (dual-channel morphology) parts of the estuary exhibit a baroclinic residual circulation. The presence of bifurcated channels in the …


Sustainable Development And Natural Governance: The Challenges Ahead, John Dernbach, Dan Tarlock Dec 2004

Sustainable Development And Natural Governance: The Challenges Ahead, John Dernbach, Dan Tarlock

John C. Dernbach

No abstract provided.


Integrating High-Precision Aftershock Locations And Geodetic Observations To Model Coseismic Deformation Associated With The 1995 Kozani-Grevena Earthquake, Greece, Phillip G. Resor, David Pollard, T J. Wright, G C. Beroza Dec 2004

Integrating High-Precision Aftershock Locations And Geodetic Observations To Model Coseismic Deformation Associated With The 1995 Kozani-Grevena Earthquake, Greece, Phillip G. Resor, David Pollard, T J. Wright, G C. Beroza

Phillip G Resor

We integrate high-precision aftershock locations with geodetic inverse modeling to create a more complete kinematic model for the Kozani-Grevena earthquake sequence. Using the double-difference algorithm, we have improved relative hypocentral locations by a factor of ∼7 and thus imaged the details of the fault network associated with the seismic sequence. The interpreted fault network consists of multiple segments including (1) a master normal fault that strikes nearly due west and dips toward the north at 43°, extending from 6 to 15 km depth; (2) an upper segment that connects the top of the seismicity to the observed surface ruptures and …


Inverting For Slip On Three-Dimensional Fault Surfaces Using Angular Dislocations, Phillip G. Resor, David Pollard, Frantz Maerten, Laurent Maerten Dec 2004

Inverting For Slip On Three-Dimensional Fault Surfaces Using Angular Dislocations, Phillip G. Resor, David Pollard, Frantz Maerten, Laurent Maerten

Phillip G Resor

The increasing quality of geodetic data (synthetic aperture radar interferometry [INSAR] dense Global Positioning System [GPS] arrays) now available to geophysicists and geologists are not fully exploited in slip-inversion procedures. Most common methods of inversion use rectangular dislocation segments to model fault ruptures and therefore oversimplify fault geometries. These geometric simplifications can lead to inconsistencies when inverting for slip on earthquake faults, and they preclude a more complete understanding of the role of fault geometry in the earthquake process. We have developed a new three-dimensional slip-inversion method based on the analytical solution for an angular dislocation in a linear-elastic, homogeneous, …


Hartford Basin Cross Section – Southington To Portland, Ct, Phillip G. Resor, J Z. Deboer Dec 2004

Hartford Basin Cross Section – Southington To Portland, Ct, Phillip G. Resor, J Z. Deboer

Phillip G Resor

No abstract provided.


Laramie Peak Shear System, Central Laramie Mountains, Wyoming, Usa: Regeneration Of The Archean Wyoming Province During Palaeoproterozoic Accretion, Phillip G. Resor, Arthur W. Snoke Dec 2004

Laramie Peak Shear System, Central Laramie Mountains, Wyoming, Usa: Regeneration Of The Archean Wyoming Province During Palaeoproterozoic Accretion, Phillip G. Resor, Arthur W. Snoke

Phillip G Resor

The Laramie Peak shear system (LPSS) is a 10 km-thick zone of heterogeneous general shear (non-coaxial) that records significant tectonic regeneration of middle-lower crustal rocks of the Archean Wyoming province. The shear system is related to the 1.78–1.74 Ga Medicine Bow orogeny that involved the collision of an oceanic-arc terrane (Colorado province or Green Mountain block or arc) with the rifted, southern margin of the Wyoming province. The style and character of deformation associated with the LPSS is distinctive: a strong, penetrative (mylonitic) foliation commonly containing a moderately steep, SW-plunging elongation lineation. In mylonitic quartzo-feldspathic gneisses of the Fletcher Park …


Western End Of The Honey Hill Fault Along The Eastern Bank Of The Connecticut River, Phillip G. Resor, J Z. Deboer Dec 2004

Western End Of The Honey Hill Fault Along The Eastern Bank Of The Connecticut River, Phillip G. Resor, J Z. Deboer

Phillip G Resor

No abstract provided.