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Geology

2013

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Articles 1 - 30 of 155

Full-Text Articles in Physical Sciences and Mathematics

A Tree-Ring Based Reconstruction Of Logan River Streamflow, Northern Utah, Eric B. Allen, Tammy M. Rittenour, R. Justin Derose, Matthew F. Bekker, Roger Kjelgren, Brendan M. Buckley Dec 2013

A Tree-Ring Based Reconstruction Of Logan River Streamflow, Northern Utah, Eric B. Allen, Tammy M. Rittenour, R. Justin Derose, Matthew F. Bekker, Roger Kjelgren, Brendan M. Buckley

Geosciences Faculty Publications

We created six new tree‐ring chronologies in northern Utah, which were used with preexisting chronologies from Utah and western Wyoming to reconstruct mean annual flow for the Logan River, the largest tributary of the regionally important Bear River. Two reconstruction models were developed, a “Local” model that incorporated two Rocky Mountain juniper chronologies located within the basin, and a “Regional” model that also included limber pine and pinyon pine chronologies from a larger area. The Local model explained 48.2% of the variability in the instrumental record and the juniper chronologies better captured streamflow variability than Douglas‐fir collected within the Logan …

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The Crustal Thickness Of West Antarctica, Julien A. Chaput, Richard C. Aster, Audrey D. Huerta, X. Sun, Andrew Lloyd, Douglas A. Wiens, Andrew Nyblade, Sridhar Anandakrishnan, J. Paul Winberry, Terry Wilson Dec 2013

The Crustal Thickness Of West Antarctica, Julien A. Chaput, Richard C. Aster, Audrey D. Huerta, X. Sun, Andrew Lloyd, Douglas A. Wiens, Andrew Nyblade, Sridhar Anandakrishnan, J. Paul Winberry, Terry Wilson

Geological Sciences Faculty Scholarship

P-to-S receiver functions (PRFs) from the Polar Earth Observing Network (POLENET) GPS and seismic leg of POLENET spanning West Antarctica and the Transantarctic Mountains deployment of seismographic stations provide new estimates of crustal thickness across West Antarctica, including the West Antarctic Rift System (WARS), Marie Byrd Land (MBL) dome, and the Transantarctic Mountains (TAM) margin. We show that complications arising from ice sheet multiples can be effectively managed and further information concerning low-velocity subglacial sediment thickness may be determined, via top-down utilization of synthetic receiver function models. We combine shallow structure constraints with the response of deeper layers using a …

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Marine Diatom Assemblage Variation Across Pleistocene Glacial-Interglacial Transitions And Neogene Diatom Biostratigraphy Of Site C9001, Nw Pacific Ocean, Marcella K. Purkey Dec 2013

Marine Diatom Assemblage Variation Across Pleistocene Glacial-Interglacial Transitions And Neogene Diatom Biostratigraphy Of Site C9001, Nw Pacific Ocean, Marcella K. Purkey

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

In 2006, D/V-Chikyu cruise CK06-06 drilled Hole C9001C at Site C9001 in the Northwest Pacific Ocean, 80 km east of the Shimokita Peninsula, Japan. An existing chronostratigraphic framework provides a continuous glacial-interglacial (GI) climate record from which a diatom record of paleoenvironmental changes was developed across several GI cycles. Species counts, diatom temperature values, calculated sea-surface temperatures (SST) and factor analysis were produced for each sample and calibrated to prior diatom studies in this region. These features were used to characterize and compare interglacial maxima of Marine Isotope Stages (MIS) 1, 5e, 9 and 11 and transitions from the preceding …

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Hydrochemical Investigation Of A Transient Parafluvial Zone Under Drought Conditions, Platte River, Nebraska, Audrey R. Boerner Dec 2013

Hydrochemical Investigation Of A Transient Parafluvial Zone Under Drought Conditions, Platte River, Nebraska, Audrey R. Boerner

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Shallow groundwater (0.5 m -1.2 m deep) beneath a vegetated and non-vegetated fluvial island was observed in the lower Platte River, Nebraska, USA during exceptional summer drought. Over the course of three months, sub-hourly measurements of hydraulic head, and weekly measurements of redox indicators, δ2H, δ18O, and dissolved gases were analyzed together with nitrogen and carbon species from an array of shallow piezometers in the river bed and islands. These data were compared with the same parameters collected from a 15 m-deep riparian borehole. Vertical hydraulic gradients in the island piezometers indicated the vertical component to …

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Glacier Slip And Seismicity Induced By Surface Melt, Peter L. Moore, J. Paul Winberry, Neal R. Iverson, Knut A. Christianson, Sridhar Anandakrishnan, Miriam Jackson, Mark E. Mathison, Denis Cohen Dec 2013

Glacier Slip And Seismicity Induced By Surface Melt, Peter L. Moore, J. Paul Winberry, Neal R. Iverson, Knut A. Christianson, Sridhar Anandakrishnan, Miriam Jackson, Mark E. Mathison, Denis Cohen

All Faculty Scholarship for the College of the Sciences

Many of the key processes governing fast glacier flow involve interaction between a glacier and its basal hydrological system, which is hidden from direct observation. Passive seismic monitoring has shown promise as a tool for remotely monitoring basal processes, but lack of glacier-bed access prevents clear understanding of the relationships between subglacial processes and corresponding seismic emissions. Here we describe direct measurements of basal hydrology, sliding, and broadband seismicity made in a unique subglacial facility in Norway during the onset of two summer melt seasons. In the most pronounced of these episodes, rapid delivery of surface meltwater to the bed …

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Chemical Eor, Ibnelwaleed A. Hussein, Yujun Feng, Baojun Bai Dec 2013

Chemical Eor, Ibnelwaleed A. Hussein, Yujun Feng, Baojun Bai

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

No abstract provided.

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Sources Of Co2 Controlling The Carbonate Chemistry Of The Logsdon River, Mammoth Cave, Kentucky, Bruce Elliott Hatcher Dec 2013

Sources Of Co2 Controlling The Carbonate Chemistry Of The Logsdon River, Mammoth Cave, Kentucky, Bruce Elliott Hatcher

Masters Theses & Specialist Projects

Logsdon River is a major, base-level stream within the Turnhole Bend Drainage basin of the Mammoth Cave System. The Logsdon River system has provided a unique opportunity to examine the geochemical evolution of a stream flowing through a major karst conduit that can be traversed for 10 km. This study examines CO2 inputs at the upstream portion of the river, which provide major control for the river’s hydrochemistry. Samples were collected from the upstream portion of Logsdon River at what is referred to as the S-188 sump and also nearby at Crowbar Dome over the course of 44 weeks …

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Eastern Deciduous Forest Phenology And Vegetative Vigor Trends From 2000 To 2013, Mammoth Cave National Park, Ky, Sean Taylor Hutchison Dec 2013

Eastern Deciduous Forest Phenology And Vegetative Vigor Trends From 2000 To 2013, Mammoth Cave National Park, Ky, Sean Taylor Hutchison

Masters Theses & Specialist Projects

Global climate change is predicted to affect environmental systems at the midlatitudes, but the scope, severity, and outcomes of these impacts are yet to be fully understood. This study focuses on the implications of short-term climate variability for forests in central Kentucky. Using a Normalized Difference Vegetation Index (NDVI) calculated from MODerate-Resolution Imaging Spectroradiometer (MODIS) instrument data, the photosynthetic activity of vegetation at Mammoth Cave National Park (MACA) is tracked from 2000 to 2013. Three methods were employed to examine the changes and climate influences in vegetation over the study period: 1) aggregating the NDVI of the Park by year …

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Inferring Tidal Wetland Stability From Channel Sediment Fluxes: Observations And A Conceptual Model, Nk Ganju, Nj Nidzieko, Matthew L. Kirwan Dec 2013

Inferring Tidal Wetland Stability From Channel Sediment Fluxes: Observations And A Conceptual Model, Nk Ganju, Nj Nidzieko, Matthew L. Kirwan

VIMS Articles

Anthropogenic and climatic forces have modified the geomorphology of tidal wetlands over a range of timescales. Changes in land use, sediment supply, river flow, storminess, and sea level alter the layout of tidal channels, intertidal flats, and marsh plains; these elements define wetland complexes. Diagnostically, measurements of net sediment fluxes through tidal channels are high-temporal resolution, spatially integrated quantities that indicate (1) whether a complex is stable over seasonal timescales and (2) what mechanisms are leading to that state. We estimated sediment fluxes through tidal channels draining wetland complexes on the Blackwater and Transquaking Rivers, Maryland, USA. While the Blackwater …

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Global Digital Elevation Model Accuracy Assessment In The Himalaya, Nepal, Luke G. Miles Dec 2013

Global Digital Elevation Model Accuracy Assessment In The Himalaya, Nepal, Luke G. Miles

Masters Theses & Specialist Projects

Digital Elevation Models (DEMs) are digital representations of surface topography or terrain. Collection of DEM data can be done directly through surveying and taking ground control point (GCP) data in the field or indirectly with remote sensing using a variety of techniques. The accuracies of DEM data can be problematic, especially in rugged terrain or when differing data acquisition techniques are combined. For the present study, ground data were taken in various protected areas in the mountainous regions of Nepal. Elevation, slope, and aspect were measured at nearly 2000 locations. These ground data were imported into a Geographic Information System …

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La Yeguada Volcanic Vomplex In The Republic Of Panama: An Assessment Of The Geologic Hazards Using 40ar/39ar Geochronology, Karinne L. Knutsen, William I. Rose, Brian Jicha Nov 2013

La Yeguada Volcanic Vomplex In The Republic Of Panama: An Assessment Of The Geologic Hazards Using 40ar/39ar Geochronology, Karinne L. Knutsen, William I. Rose, Brian Jicha

Department of Geological and Mining Engineering and Sciences Publications

La Yeguada volcanic complex is one of three Quaternary volcanic centers in Panama. To assess potential geologic hazards, new samples were analyzed using argon analysis (40Ar/39Ar), and obtained the following: the most recent eruption occurred approximately 32,000 years ago at the Media Luna cinder cone; the youngest dated eruption from the main dome complex occurred 357 ± 19 ka, producing the Castillo dome unit; Cerro Picacho, a separate dacite dome 1.5 km east of the main complex is 4.47 ± 0.23 Ma; and the El Satro Pyroclastic Flow unit surrounds the northern portion of the volcanic …

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Seismic Slip Deficit In The Kashmir Himalaya From Gps Observations, Celia Schiffman, Bikram Singh Bali, Walter Szeliga, Roger Bilham Nov 2013

Seismic Slip Deficit In The Kashmir Himalaya From Gps Observations, Celia Schiffman, Bikram Singh Bali, Walter Szeliga, Roger Bilham

Faculty Scholarship for the Cascadia Hazards Institute

GPS measurements in Kashmir Himalaya reveal rangenormal convergence of 11±1 mm/yr with dextral shear of 5±1 mm/yr. The transition from a fully locked 170 km wide décollement to the unrestrained descending Indian plate occurs at ~25 km depth over an ~23 km wide transition zone. The convergence rate is consistent with the lower bounds of geological estimates for the Main Frontal Thrust, Riasi, and Balapora fault systems, on which no surface slip has been reported in the past millennium. Of the 14 damaging Kashmir earthquakes since 1123, none may have exceeded Mw = 7.6. Therefore, either a seismic moment …

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Reverse-Time Migration-Based Reflection Tomography Using Teleseismic Free Surface Multiples, S. Burdick, M. V. De Hoop, R. D. Van Der Hilst Nov 2013

Reverse-Time Migration-Based Reflection Tomography Using Teleseismic Free Surface Multiples, S. Burdick, M. V. De Hoop, R. D. Van Der Hilst

Environmental Science and Geology Faculty Research Publications

Converted and multiply reflected phases from teleseismic events are routinely used to create structural images of the crust–mantle boundary (Moho) and the elasticity contrasts within the crust and upper mantle. The accuracy of these images is to a large extent determined by the background velocity model used to propagate these phases to depth. In order to improve estimates of 3-D velocity variations and, hence, improve imaging, we develop a method of reverse-time migration-based reflection tomography for use with wavefields from teleseismic earthquakes recorded at broad-band seismograph arrays. Reflection tomography makes use of data redundancy—that is, the ability to generate numerous …

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The Western Kentucky University Crumps Cave Research & Education Preserve, Chris Groves, Jason Polk, Ben Miller, Pat Kambesis, Carl Bolster, Sean Vanderhoff, Beth Tyrie Nov 2013

The Western Kentucky University Crumps Cave Research & Education Preserve, Chris Groves, Jason Polk, Ben Miller, Pat Kambesis, Carl Bolster, Sean Vanderhoff, Beth Tyrie

Earth, Environmental, and Atmospheric Sciences Faculty Publications

Crumps Cave is located about one kilometer northeast of Smiths Grove, Kentucky (Figures 1, 2, and 3). The only known entrance was purchased by Western Kentucky University (WKU) in 2009 through a grant from the Kentucky Heritage Land Conservation Fund and the cave is managed as the focal point of a research and education preserve to study a wide range of environmental conditions and dynamics, and their interactions, using high-resolution electronic monitoring along with geochemical sampling, analysis and modeling. Crews from WKU’s Hoffman Environmental Research Institute visit the cave weekly for sampling, data downloading, and equipment maintenance, with a major …

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Melt Inclusion Evidence For Magma Evolution At Mutnovsky Volcano, Kamchatka, K. Robertson, A. Simon, T. Pettke, Sean R. Mulcahy, E. Smith, O. Selyangin, A. Kiryukhin, J. D. Walker Nov 2013

Melt Inclusion Evidence For Magma Evolution At Mutnovsky Volcano, Kamchatka, K. Robertson, A. Simon, T. Pettke, Sean R. Mulcahy, E. Smith, O. Selyangin, A. Kiryukhin, J. D. Walker

Geology Faculty Publications

Mutnovsky Volcano, located in Kamchatka, Russia, is a young volcano that has formed a series of four overlapping stratocones over its approximately 80 ka history. Erupted products at Mutnovsky range in composition from basalts to dacites; basalts are the most common. In this study, melt inclusions from representative samples of all erupted compositions from all four eruptive centers were analyzed to investigate the causes of the compositional heterogeneity, melt evolution, and pre-eruptive magma dynamics. Melt inclusions from Mutnovsky were sampled in olivine, plagioclase, orthopyroxene, and clinopyroxene. The melt inclusion data represent a wide range of melt compositions, from basalt through …

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An Apparent Angular Unconformity In Western Connecticut, Stanley Schleifer, Nazrul I. Khandaker, Adisa Charles, Hernando Martinez, Shirley Jackson, Chiemeka Ihebom Oct 2013

An Apparent Angular Unconformity In Western Connecticut, Stanley Schleifer, Nazrul I. Khandaker, Adisa Charles, Hernando Martinez, Shirley Jackson, Chiemeka Ihebom

Publications and Research

The recent extension, to the north, of the U. S. Route 7 ‘superhighway’ in the town of Brookfield, Connecticut has involved the excavation of crystalline bedrock of lower Paleozoic to upper Proterozoic age in the area. The road cuts produced by this excavation have exposed some interesting features of structure and lithology. An outcrop, observed by the authors off the east side of route 7, at grid coordinates 41.482444 N, 73.415307 W is of particular interest. It appears, to the casual observer to be an angular unconformity. Maps and publications regarding this area of Western Connecticut support the likelihood of …

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Ichnogenic Megaporosity And Permeability In Carbonate Aquifers And Reservoirs: Definitions And Examples, H. Allen Curran, Kevin J. Cunningham Oct 2013

Ichnogenic Megaporosity And Permeability In Carbonate Aquifers And Reservoirs: Definitions And Examples, H. Allen Curran, Kevin J. Cunningham

Geosciences: Faculty Publications

Biogenic megaporosity in sedimentary deposits (readily visible without magnification) typically has body-fossil moldic or ichnogenic origin. We consider ichnogenic megaporosity as pores greater than 4 mm associated with either burrow- or rhizolith-dominated ichnofabrics. Dominant bioturbators in shallow-marine environments typically include thalassinidean crustaceans and polychaetes. Callianassid shrimp commonly dominate the deep-tier fauna in carbonate and siliciclastic, sandy, shallow-marine settings; when fossilized their thickly lined, pelleted burrows (cm-scale outside diameters) are assigned to the ichnogenus Ophiomorpha. In the mostly Pleistocene carbonate rocks of the Biscayne aquifer of south Florida, Ophiomorpha is well lithified and burrows form a rigid framework, with interburrow macroporosity …

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Geogram 2013, David J. Keeling Editor, Wku Department Of Geography And Geology Oct 2013

Geogram 2013, David J. Keeling Editor, Wku Department Of Geography And Geology

Earth, Environmental, and Atmospheric Sciences Publications

No abstract provided.

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Rapid River Incision Across An Inactive Fault - Implications For Patterns Of Erosion And Deformation In The Central Colorado Plateau, Joel L. Pederson, Neil Burnside, Zoe Shipton, Tammy M. Rittenour Oct 2013

Rapid River Incision Across An Inactive Fault - Implications For Patterns Of Erosion And Deformation In The Central Colorado Plateau, Joel L. Pederson, Neil Burnside, Zoe Shipton, Tammy M. Rittenour

Geosciences Faculty Publications

The Colorado Plateau presents a contrast between deep and seemingly recent erosion and apparently only mild late Cenozoic tectonic activity. Researchers have recently proposed multiple sources of epeirogenic uplift and intriguing patterns of differential incision, yet little or no quantitative constraints exist in the heart of the plateau to test these ideas. Here, we use both optically stimulated luminescence (OSL) and uranium-series dating to delimit the record of fluvial strath terraces at Crystal Geyser in southeastern Utah, where the Little Grand Wash fault crosses the Green River in the broad Mancos Shale badlands of the central plateau. Results indicate there …

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Limits Of Luminescence Dating: An Update Regarding Quartz Of The Southern Alps Of New Zealand And The Olympic Mountains, Washington, Usa, Cianna E. Wyshnytzky, Tammy M. Rittenour Oct 2013

Limits Of Luminescence Dating: An Update Regarding Quartz Of The Southern Alps Of New Zealand And The Olympic Mountains, Washington, Usa, Cianna E. Wyshnytzky, Tammy M. Rittenour

Graduate Student Posters

Late Pleistocene glacial sediments from the South Fork Hoh River valley in the Olympic Mountains, Washington, USA and the Lake Hawea valley in the Southern Alps, New Zealand were dated using optically stimulated luminescence (OSL) on quartz and infrared stimulated luminescence (IRSL) on feldspar sand from 2011-2013. High sediment supply (typical of glacial environments), short transport distances, and sediment newly eroded from bedrock sources were expected to pose problems for luminescence dating in these locations. Samples were collected from a variety of depositional environments and inferred distances from the ice-front to assess how luminescence signals may vary due to these …

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Stratigraphic Framework, Discontinuity Surfaces, And Regional Significance Of Campanian Slope To Ramp Carbonates From Central Dalmatia, Croatia, M. Brlek, T. Korbar, B. Cvetko Tešović, B. Glumac, L. Fuček Oct 2013

Stratigraphic Framework, Discontinuity Surfaces, And Regional Significance Of Campanian Slope To Ramp Carbonates From Central Dalmatia, Croatia, M. Brlek, T. Korbar, B. Cvetko Tešović, B. Glumac, L. Fuček

Geosciences: Faculty Publications

The sedimentology, microfacies, and stratigraphic age (from planktonic and benthic foraminifera and strontium-isotope stratigraphy) of a 300-m-thick Upper Cretaceous carbonate succession from the Island of Čiovo (central Dalmatia, Croatia) were analyzed in order to determine the lithostratigraphic, depositional, and chronostratigraphic framework. The Cretaceous strata were deposited in the southern part of the long-lasting (Late Triassic to Paleogene) Adriatic-Dinaridic Carbonate Platform (ADCP), one of a few late Mesozoic, intra-Tethyan, peri-Adriatic (sub)tropical archipelagos. The succession is separated by a firmground formational boundary into two lithostratigraphic units: the underlying Middle to Upper Campanian Dol Formation consisting of slope pelagic limestone with intercalated turbidites …

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Making Reliable Shear-Wave Splitting Measurements, Kelly H. Liu, Stephen S. Gao Oct 2013

Making Reliable Shear-Wave Splitting Measurements, Kelly H. Liu, Stephen S. Gao

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Shear-wave splitting (SWS) analysis using SKS, SKKS, and PKS (hereafter collectively called XKS) phases is one of the most commonly used techniques in structural seismology. In spite of the apparent simplicity in performing SWS measurements, large discrepancies in published SWS parameters (fast direction and splitting time) suggest that a significant portion of splitting parameters has been incorrectly determined. Here, based on the popularly used minimization of transverse energy technique, we present a procedure that combines automatic data processing and careful manual screening, which includes adjusting the XKS window used for splitting analysis, modifying band-pass filtering corner frequencies, and verifying and …

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Late Holocene Tsunami Deposits At Salt Creek, Washington, Usa, Ian Hutchinson, Curt D. Peterson, Sarah L. Sterling Oct 2013

Late Holocene Tsunami Deposits At Salt Creek, Washington, Usa, Ian Hutchinson, Curt D. Peterson, Sarah L. Sterling

Anthropology Faculty Publications and Presentations

We interpret two thin sand layers in the estuarine marsh at Salt Creek, on the southern shore of the Strait of Juan de Fuca, as the products of tsunamis propagated by earthquakes at the Cascadia subduction zone. The sand layers extend for about 60 m along the left bank of the creek about 800 m from the mouth, and can be traced to the base of a nearby upland area. One layer is exposed in the creek bank about 400 m further upstream, but they are only patchily distributed in the rest of the central area of the marsh. Both …

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Phanerozoic Surface History Of The Slavecraton, Alexis K. Ault, Rebecca M. Flowers, Samuel A. Bowring Sep 2013

Phanerozoic Surface History Of The Slavecraton, Alexis K. Ault, Rebecca M. Flowers, Samuel A. Bowring

Geosciences Faculty Publications

New apatite (U-Th)/He (AHe) thermochronometry data and key geologic constraints from Slave craton kimberlites are used to develop a model for the Phanerozoic burial, unroofing, and hypsometric history of the northwestern Canadian shield. AHe dates range from 210 ± 13 to 382 ± 79 Ma, are older in the eastern Slave craton and decrease westward, and resolve the spatial extent, thickness, and history of now-denuded sedimentary units. Results indicate Paleozoic heating to temperatures ≥85–90°C, suggesting regional burial beneath ≥2.8 km of strata while the region was at sea level, followed by the westward migration of unroofing across the craton. This …

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Paleoseismology Of The Southern Panamint Valley Fault: Implications For Regional Earthquake Occurrence And Seismic Hazard In Southern California, Lee J. Mcauliffe, James F. Dolan, Eric Kirby, Chris Rollins, Ben Haravitch, Steve Alm, Tammy M. Rittenour Sep 2013

Paleoseismology Of The Southern Panamint Valley Fault: Implications For Regional Earthquake Occurrence And Seismic Hazard In Southern California, Lee J. Mcauliffe, James F. Dolan, Eric Kirby, Chris Rollins, Ben Haravitch, Steve Alm, Tammy M. Rittenour

Geosciences Faculty Publications

[1] Paleoseismologic data from the southern Panamint Valley fault (PVF) reveal evidence of at least four surface ruptures during late Holocene time (0.33–0.48 ka, 0.9–3.0 ka, 3.3–3.6 ka, and >4.1 ka). These paleo‐earthquake ages indicate that the southern PVF has ruptured at least once and possibly twice during the ongoing (≤1.5 ka) seismic cluster in the Mojave section of the eastern California shear zone (ECSZ). The most recent event (MRE) on the PVF is also similar in age to the 1872 Owens Valley earthquake and the geomorphically youthful MRE on the Death Valley fault. The timing of the three oldest …

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Wmu Research Facility Assists In Rediscovery Of Rare Mineral Deposit, Cheryl Roland Sep 2013

Wmu Research Facility Assists In Rediscovery Of Rare Mineral Deposit, Cheryl Roland

MGRRE News

WMU News article about the rediscovery of a long-forgotten mineral deposit, potash, which is located under two West Michigan counties.

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Scavenging, Cycling And Removal Fluxes Of 210Po And 210Pb At The Bermuda Time-Series Study Site, G. H. Hong, M. Baskaran, T. M. Church, M. Conte Sep 2013

Scavenging, Cycling And Removal Fluxes Of 210Po And 210Pb At The Bermuda Time-Series Study Site, G. H. Hong, M. Baskaran, T. M. Church, M. Conte

Environmental Science and Geology Faculty Research Publications

Quantifying relative affinities of Po and Pb in different populations of marine particulate matter is of great importance in utilizing 210Po as a tracer for carbon cycling. We collected and analyzed water samples for the concentrations of dissolved and total 210Po and 210Pb from the upper 600 m of the water column at Bermuda Time-series Study site (September 1999 to September 2000) to investigate their seasonality of concentrations and their ac-tivity ratio (210Po/210Pb activity ratio, AR). Sinking particles collected in sediment traps at depths of 500 m, 1500 m, and 3200 m from …

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Self-Potential Signals Generated By The Corrosion Of Buried Metallic Objects With Application To Contaminant Plumes, Justin B. R. Rittgers, Andre Revil, Marios C. Karaoulis, Michael A. Mooney, Lee D. Slater, Estella A. Atekwana Sep 2013

Self-Potential Signals Generated By The Corrosion Of Buried Metallic Objects With Application To Contaminant Plumes, Justin B. R. Rittgers, Andre Revil, Marios C. Karaoulis, Michael A. Mooney, Lee D. Slater, Estella A. Atekwana

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Large-amplitude (>100 mV) negative electric (self)-potential anomalies are often observed in the vicinity of buried metallic objects and ore bodies or over groundwater plumes associated with organic contaminants. To explain the physical and chemical mechanisms that generate such electrical signals, a controlled laboratory experiment was carried out involving two metallic cylinders buried with vertical and horizontal orientations and centered through and in the capillary fringe within a sandbox. The 2D and 3D self-potential (SP) data were collected at several time steps along with collocated pH and redox potential measurements. Large dipolar SP and redox potential anomalies developed in association …

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Accommodation Space Controls On The Latest Pleistocene And Holocene (16–0 Ka) Sediment Size And Bypassing In The Lower Columbia River Valley: A Large Fluvial–Tidal System In Oregon And Washington, Usa, Curt D. Peterson Sep 2013

Accommodation Space Controls On The Latest Pleistocene And Holocene (16–0 Ka) Sediment Size And Bypassing In The Lower Columbia River Valley: A Large Fluvial–Tidal System In Oregon And Washington, Usa, Curt D. Peterson

Geology Faculty Publications and Presentations

In this study, we establish the roles that increasing basin accommodation space have on sediment size and bypassing in the transgressive fill (16–0 ka) in the submerged Lower Columbia River Valley (LCRV). The antecedent forearc valley (225 km in length, 4–8 km in width, and 60–115 m in axial valley depth) is characterized by high sediment supply rates (10–15 million t y-1) but no delta at its mouth to the Pacific Ocean. Core sample sediment textures (N ¼ 1600) are analyzed from 3000 m of borehole sections in 58 representative boreholes to characterize the ancestral valley fill: 57% sand, 17% …

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Integrated Geophysical Investigation Of The St. James Fault Complex: A Case Study, Robert W. Jacob, Jeremy B. Byler, Mary Beth Gray Sep 2013

Integrated Geophysical Investigation Of The St. James Fault Complex: A Case Study, Robert W. Jacob, Jeremy B. Byler, Mary Beth Gray

Faculty Journal Articles

We noninvasively detected the characteristics and location of a regional fault in an area of poor bedrock exposure complicated by karst weathering features in the subsurface. Because this regional fault is associated with sinkhole formation, its location is important for hazard avoidance. The bedrock lithologies on either side of the fault trace are similar; hence, we chose an approach that capitalized on the complementary strengths of very low frequency (VLF) electromagnetic, resistivity, and gravity methods. VLF proved most useful as a first-order reconnaissance tool, allowing us to define a narrow target area for further geophysical exploration. Fault-related epikarst was delineated …

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