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2015

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Full-Text Articles in Earth Sciences

Hybrid Cement Clinker And Cement Made From That Clinker, Thomas Robl, Tristana Y. Duvallet, Robert Rathbone, Yongnin Zhou Mar 2015

Hybrid Cement Clinker And Cement Made From That Clinker, Thomas Robl, Tristana Y. Duvallet, Robert Rathbone, Yongnin Zhou

Earth and Environmental Sciences Faculty Patents

A hybrid cement clinker incorporates specific ranges of clinker phases and falls within specific modulus values as set forth and described in this document.


The Speleogenesis Of Vallgornera Cave (Mallorca, Spain): A Mineralogical And Morphological Study, Jacqueline Amelia Diehl Mar 2015

The Speleogenesis Of Vallgornera Cave (Mallorca, Spain): A Mineralogical And Morphological Study, Jacqueline Amelia Diehl

USF Tampa Graduate Theses and Dissertations

Cova des Pas de Vallgornera (CPV) is morphologically and scientifically, the most prominent karst feature of Mallorca Island (Spain). It consists of over 74 km of passages developed within two carbonate lithologies (reef front and back reef facies) of Upper Miocene age. Two distinct cave patterns are recognized, both tightly controlled by the type of facies; spongework mazes and collapse chambers are characteristic for the reef front unit, whereas linear, fracture-guided galleries develop in the back reef carbonates. CPV is abundantly decorated with a variety of speleothems.

The overarching goal of this study is to provide evidence towards the cave's …


Changes In Spatial Patterns Of Caragana Stenophylla Along A Climatic Drought Gradient On The Inner Mongolian Plateau, Li-Na Xie, Hong-Yu Guo, Christopher A. Gabler, Qing-Fang Li, Cheng-Cang Ma Mar 2015

Changes In Spatial Patterns Of Caragana Stenophylla Along A Climatic Drought Gradient On The Inner Mongolian Plateau, Li-Na Xie, Hong-Yu Guo, Christopher A. Gabler, Qing-Fang Li, Cheng-Cang Ma

School of Earth, Environmental, & Marine Sciences Faculty Publications

Few studies have investigated the influence of water availability on plant population spatial patterns. We studied changes in the spatial patterns of Caragana stenophylla along a climatic drought gradient within the Inner Mongolian Plateau, China. We examined spatial patterns, seed density, “nurse effects” of shrubs on seedlings, transpiration rates and water use efficiency (WUE) of C. stenophylla across semi-arid, arid, and intensively arid zones. Our results showed that patches of C. stenophylla populations shifted from a random to a clumped spatial pattern towards drier environments. Seed density and seedling survival rate of C. stenophylla decreased from the semi-arid zone to …


U.S. Drought Monitor, March 17, 2015, Chris Fenimore Mar 2015

U.S. Drought Monitor, March 17, 2015, Chris Fenimore

United States Agricultural Commodities in Drought Archive

Drought map of U.S. for March 17, 2015 (3/17/15) plus: U.S. crop areas experiencing drought (map), Approximate percentage of crop located in drought, by state (bar graph), Percent of crop area located in drought, past 52 weeks (line graph) for: Corn, Soybeans, Hay, Cattle, Winter wheat.


A Meta-Analysis Of Soil Biodiversity Impacts On The Carbon Cycle, M.-A. De Graaff, J. Adkins, P. Kardol, H. L. Throop Mar 2015

A Meta-Analysis Of Soil Biodiversity Impacts On The Carbon Cycle, M.-A. De Graaff, J. Adkins, P. Kardol, H. L. Throop

Biology Faculty Publications and Presentations

Loss of biodiversity impacts ecosystem functions, such as carbon (C) cycling. Soils are the largest terrestrial C reservoir, containing more C globally than the biotic and atmospheric pools together. As such, soil C cycling, and the processes controlling it, has the potential to affect atmospheric CO2 concentrations and subsequent climate change. Despite the growing evidence of links between plant diversity and soil C cycling, there is a dearth of information on whether similar relationships exist between soil biodiversity and C cycling. This knowledge gap occurs even though there has been increased recognition that soil communities display high levels of …


The Relationship Between Carbon Dioxide Concentration And Visitor Numbers In The Homothermic Zone Of The Balcarka Cave (Moravian Karst) During A Period Of Limited Ventilation, Marek Lang, Jiří Faimon, Camille Ek Mar 2015

The Relationship Between Carbon Dioxide Concentration And Visitor Numbers In The Homothermic Zone Of The Balcarka Cave (Moravian Karst) During A Period Of Limited Ventilation, Marek Lang, Jiří Faimon, Camille Ek

International Journal of Speleology

The evolution of CO2 levels with and without human presence was studied in a selected site (Gallery Chamber) of the homothermic zone of the Balcarka Cave (Moravian Karst, Czech Republic) during the fall, a period of limited ventilation. There were recognized various factors controlling the cave CO2 levels under different conditions in the exterior and interior. When visitors were absent, CO2 levels were controlled by the advective CO2 fluxes linked to cave airflows and reaching up to ~1.5x10-3 mol s-1. These fluxes exceed by orders of magnitude the exchanged diffusive fluxes (up to …


A Novel Approach To Flow And Sediment Transport Estimation In Estuaries And Bays, Hamed Moftakhari Rostamkhani Mar 2015

A Novel Approach To Flow And Sediment Transport Estimation In Estuaries And Bays, Hamed Moftakhari Rostamkhani

Dissertations and Theses

Reliable estimates of river discharge and sediment transport to the ocean from large tidal rivers are vital for water resources management, efficient river and harbor management, navigational purposes, and climate analyses. Due to the difficulties inherent in measuring tidal-river discharge, hydrological and sedimentological records are typically too short to adequately characterize long-term (decadal) trends. Also, uncertainties associated with observation and calibration of hydrological models suggest a need for more accurate methods based on longer records of hydrodynamic parameters (e.g. tides). Tidal theory indicates that tides and river discharge interact through quadratic bed friction, which diminishes and distorts the tidal wave …


U.S. Drought Monitor, March 10, 2015, Matthew Rosencrans Mar 2015

U.S. Drought Monitor, March 10, 2015, Matthew Rosencrans

United States Agricultural Commodities in Drought Archive

Drought map of U.S. for March 10, 2015 (3/10/15) plus: U.S. crop areas experiencing drought (map), Approximate percentage of crop located in drought, by state (bar graph), Percent of crop area located in drought, past 52 weeks (line graph) for: Corn, Soybeans, Hay, Cattle, Winter wheat.


Functional Anatomy Of The Forelimb Of A New Drepanosaur: Testing Behavioral Models For Extinct Species, Austin Andrus, Dr. Brooks Britt Mar 2015

Functional Anatomy Of The Forelimb Of A New Drepanosaur: Testing Behavioral Models For Extinct Species, Austin Andrus, Dr. Brooks Britt

Journal of Undergraduate Research

Introduction: I recently discovered a new genus of reptile from the Triassic period (roughly 225 million years ago). Reptiles like it are called “drepanosaurs,” and share many unique features such as large claws, unusual, humped shoulder blades, opposable fingers, and prehensile tails. Many of these structures appear to be well-suited for climbing, and the scientific community generally considers drepanosaurs to be arboreal. My new specimen, however, is more complete than previous discoveries have been, and it includes skeletal features that could indicate a digging lifestyle. Digging and climbing are on opposite ends of the behavioral spectrum, so my study seeks …


Assessment Of Surface Soil Moisture Using High-Resolution Multi-Spectral Imagery And Artificial Neural Networks, Leila Hassan-Esfahani, Alfonso Torres-Rua, Austin Jensen, Mac Mckee Mar 2015

Assessment Of Surface Soil Moisture Using High-Resolution Multi-Spectral Imagery And Artificial Neural Networks, Leila Hassan-Esfahani, Alfonso Torres-Rua, Austin Jensen, Mac Mckee

AggieAir Publications

Many crop production management decisions can be informed using data from high-resolution aerial images that provide information about crop health as influenced by soil fertility and moisture. Surface soil moisture is a key component of soil water balance, which addresses water and energy exchanges at the surface/atmosphere interface; however, high-resolution remotely sensed data is rarely used to acquire soil moisture values. In this study, an artificial neural network (ANN) model was developed to quantify the effectiveness of using spectral images to estimate surface soil moisture. The model produces acceptable estimations of surface soil moisture (root mean square error (RMSE) = …


U.S. Drought Monitor, March 3, 2015, David Simeral Mar 2015

U.S. Drought Monitor, March 3, 2015, David Simeral

United States Agricultural Commodities in Drought Archive

Drought map of U.S. for March 3, 2015 (3/3/15) plus: U.S. crop areas experiencing drought (map), Approximate percentage of crop located in drought, by state (bar graph), Percent of crop area located in drought, past 52 weeks (line graph) for: Corn, Soybeans, Hay, Cattle, Winter wheat.


Hydrographic Surveys At Seven Chutes And Three Backwaters On The Missouri River In Nebraska, Iowa, And Missouri, 2011-13, Justin R. Krahulik, Brenda K. Densmore, Kayla J. Anderson, Cory L. Kavan Mar 2015

Hydrographic Surveys At Seven Chutes And Three Backwaters On The Missouri River In Nebraska, Iowa, And Missouri, 2011-13, Justin R. Krahulik, Brenda K. Densmore, Kayla J. Anderson, Cory L. Kavan

United States Geological Survey: Water Reports and Publications

The United States Geological Survey (USGS) cooperated with the United States Army Corps of Engineers (USACE), Omaha District, to complete hydrographic surveys of seven chutes and three backwaters on the Missouri River yearly during 2011–13. These chutes and backwaters were constructed by the USACE to increase the amount of available shallow water habitat (SWH) to support threatened and endangered species, as required by the amended “2000 Biological Opinion” on the operation of the Missouri River main-stem reservoir system. Chutes surveyed included Council chute, Plattsmouth chute, Tobacco chute, Upper Hamburg chute, Lower Hamburg chute, Kansas chute, and Deroin chute. Backwaters surveyed …


Nebraska’S Natural Resources Districts: An Assessment Of A Large-Scale Locally Controlled Water Governance Framework, Ann Bleed, Christina Hoffman Babbitt Mar 2015

Nebraska’S Natural Resources Districts: An Assessment Of A Large-Scale Locally Controlled Water Governance Framework, Ann Bleed, Christina Hoffman Babbitt

Daugherty Water for Food Global Institute: Faculty Publications

In 1972 the State of Nebraska created the Natural Resources Districts (NRDs) to consolidate a multitude of single-purpose local natural resource districts into a more comprehensive, holistic, and efficient natural resources governance system. While consolidation and efficiency was important, so was the concept of maintaining local control. Thus, Nebraska rejected the governance framework of a single top-down state agency, preferring to create NRDs that are each governed by a locally elected board. The locally elected governing boards of the NRDs were given broad authorities over many of the state’s natural resources, including groundwater. Such a governance structure was, and to …


Natural And Anthropogenic Processes Contributing To Metal Enrichment In Surface Soils Of Central Pennsylvania, A. M.L. Kraepiel, Ashlee L.D. Dere, E. M. Herndon, Susan L. Brantley Mar 2015

Natural And Anthropogenic Processes Contributing To Metal Enrichment In Surface Soils Of Central Pennsylvania, A. M.L. Kraepiel, Ashlee L.D. Dere, E. M. Herndon, Susan L. Brantley

Geography and Geology Faculty Publications

Metals in soils may positively or negatively affect plants as well as soil micro-organisms and mesofauna, depending on their abundance and bioavailability. Atmospheric deposition and biological uplift commonly result in metal enrichment in surface soils, but the relative importance of these processes is not always resolved. Here, we used an integrated approach to study the cycling of phosphorus and a suite of metals from the soil to the canopy (and back) in a temperate watershed. The behavior of elements in these surface soils fell into three categories. First, Al, Fe, V, Co, and Cr showed little to no enrichment in …


How Geophysicists' Intuition Helps Seismic Data Processing, Afshin Gholamy, Vladik Kreinovich Mar 2015

How Geophysicists' Intuition Helps Seismic Data Processing, Afshin Gholamy, Vladik Kreinovich

Departmental Technical Reports (CS)

In geophysics, signals come with noise. It is desirable to minimize the effect of this noise. If we knew the probabilities of different values of signal and noise, we could use statistical filtering techniques. In geophysics, however, we rarely know the exact values of these probabilities; instead, we have to rely on the expertise and intuition of experts. We show how fuzzy techniques can transform this expertise into precise de-noising methods, we explain that the resulting methods indeed satisfy several natural requirements, and that these methods are in good accordance with heuristic techniques successfully used by geophysicists.


Preliminary Soil And Groundwater Assessment Of The Mantinea Development Area, East Kimberley, Western Australia, Gregory Paul Raper, Richard J. George Dr, Noel Schoknecht Mar 2015

Preliminary Soil And Groundwater Assessment Of The Mantinea Development Area, East Kimberley, Western Australia, Gregory Paul Raper, Richard J. George Dr, Noel Schoknecht

Resource management technical reports

In 2008, the Ord Stage 2 or ‘Ord East Kimberley Expansion Project’ was initiated by the Western Australian Government. The goal of the project was to advance development in the East Kimberley and to bring to market the Weaber Plain (Goomig Farmlands) and Knox Plain. In addition to the existing Ord River Irrigation Area (ORIA) Stage 1 (14 000ha), current Goomig and proposed Knox Plain areas (14 300ha), an estimated 50 000ha of land has potential for irrigation in the region.

One of the areas proposed for future development is the Mantinea Development area. It is located on the south …


Split-Beam Echosounder Observations Of Natural Methane Seep Variability In The Northern Gulf Of Mexico, Kevin W. Jerram, Thomas C. Weber, Jonathan Beaudoin Mar 2015

Split-Beam Echosounder Observations Of Natural Methane Seep Variability In The Northern Gulf Of Mexico, Kevin W. Jerram, Thomas C. Weber, Jonathan Beaudoin

Center for Coastal and Ocean Mapping

A method for positioning and characterizing plumes of bubbles from marine gas seeps using an 18 kHz scientific split-beam echo sounder (SBES) was developed and applied to acoustic observations of plumes of presumed methane gas bubbles originating at approximately 1400 m depth in the northern Gulf of Mexico. A total of 161 plume observations from 27 repeat surveys were grouped by proximity into 35 clusters of gas vent positions on the seafloor. Profiles of acoustic target strength per vertical meter of plume height were calculated with compensation for both the SBES beam pattern and the geometry of plume ensonification. These …


Umphlett Qci March 2015, Natalie Umphlett Mar 2015

Umphlett Qci March 2015, Natalie Umphlett

High Plains Regional Climate Center: Staff Publications

Highlights for the Basin

Temperature and Precipitation Anomalies

Mountain Snowpack

Agriculture

Recreation and Tourism

Forestry

Drought Impacts Continue

3-Month Precipitation and Temperature Outlooks

U.S. Seasonal Drought Outlook


Fossils Of Putative Marine Algae From The Cryogenian Glacial Interlude Of Mongolia, Phoebe A. Cohen, Francis A. Macdonald, Sara Pruss, Emily Matys, Tanja Bosak Mar 2015

Fossils Of Putative Marine Algae From The Cryogenian Glacial Interlude Of Mongolia, Phoebe A. Cohen, Francis A. Macdonald, Sara Pruss, Emily Matys, Tanja Bosak

Geosciences: Faculty Publications

Neoproterozoic carbonate successions provide a new taphonomic window into the diversification of eukaryotes. We report recently discovered macroscopic organic warty sheets (MOWS) in macerates of limestone from the ca. 662-635 Ma Taishir Formation (Tsagaan Olom Group, Mongolia). Sheets are applanate. One surface contains raised ridges and conspicuous, ∼ 100-μm-tall warty protuberances with depressed tops that enclose internal cavities containing cellular structures. The Taishir MOWS may be the remains of unusual bacterial, protistan, or fungal biofilms, or a previously undocumented, extinct taxon. However, multiple lines of evidence including the morphology of warty protuberances and the presence of cellular architecture within protuberances …


Reflection Waveform Inversion Of Ground-Penetrating Radar Data For Characterizing Thin And Ultrathin Layers Of Nonaqueous Phase Liquid Contaminants In Stratified Media, Esther Babcock, John H. Bradford Mar 2015

Reflection Waveform Inversion Of Ground-Penetrating Radar Data For Characterizing Thin And Ultrathin Layers Of Nonaqueous Phase Liquid Contaminants In Stratified Media, Esther Babcock, John H. Bradford

CGISS Publications and Presentations

Accurately quantifying thin-layer parameters by applying a targeted reflection waveform inversion methodology to ground-penetrating radar (GPR) reflection data may provide a useful tool for near-surface investigation and especially for contaminated site investigation where nonaqueous phase liquid (NAPL) contaminants are present. We implemented a targeted reflection waveform inversion algorithm to quantify thin-layer permittivity, thickness, and conductivity for NAPL thin (≤ 1/2 dominant wavelength λ) and ultrathin (≤ 1/8λ) layers using GPR reflection data. The inversion used a nonlinear grid search with a Monte Carlo scheme to initialize starting values to find the global minimum. By taking a targeted approach using a …


Lightening Strikes Twice For Dit Geomatics, Audrey Martin Mar 2015

Lightening Strikes Twice For Dit Geomatics, Audrey Martin

Articles

The Technological University Dublin (DIT) is rapidly becoming known as an international centre for excellence for all things geospatial. In September 2014, Kevin O'Mahony, a final-year BSc Geomatics student, won the international Trimble Geospatial Student Competition. Kevin is the second consecutive DIT student to win this prestigious award, following on from the success of David Hyland (BSc Geomatics) in 2012. Both students submitted their papers under the supervision of Dr Audrey Martin FSCSI FRICS, Chair of the recently accredited (by SCSI) DIT MSc in Geospatial Engineering. The worldwide student competition is held every two years and is open to all …


Results Of Archaeogeophysical Investigations Of The Fowler - Clark Farm Mattapan, Boston, Massachusetts, Brian N. Damiata, John M. Steinberg Mar 2015

Results Of Archaeogeophysical Investigations Of The Fowler - Clark Farm Mattapan, Boston, Massachusetts, Brian N. Damiata, John M. Steinberg

Andrew Fiske Memorial Center for Archaeological Research Publications

Ground penetrating radar (GPR) and Frequency-Domain Electromagnetic (FDEM) surveys were employed over an extensively modified 50 m x 65 m city lot containing a farmhouse initially constructed between 1786 and 1806 and a later barn. Both geophysical methods suggested that most of the lot had experienced substantial disturbance and that there was limited sub - surface preservation. Both the GPR and EM surveys indicated a scatter of metallic debris and other disturbance s in the back yard at depths up to 1 m. Most of the front yard also presents as disturbed, except for two unusual but limited buried surfaces …


Wayne E. Sabbe Arkansas Soil Fertility Studies 2014, Nathan A. Slaton Mar 2015

Wayne E. Sabbe Arkansas Soil Fertility Studies 2014, Nathan A. Slaton

Arkansas Agricultural Experiment Station Research Series

Rapid technological changes in crop management and production require that the research efforts be presented in an expeditious manner. The contributions of soil fertility and fertilizers are major production factors in all Arkansas crops. The studies described within will allow producers to compare their practices with the university’s research efforts. Additionally, soil-test data and fertilizer sales are presented to allow comparisons among years, crops, and other areas within Arkansas.


Sources Of Nutrient And Escherichia Coli Contamination Within The Otter Creek Watershed, Madison County, Kentucky, Nathaniel C. Crockett, Walter S. Borowski Mar 2015

Sources Of Nutrient And Escherichia Coli Contamination Within The Otter Creek Watershed, Madison County, Kentucky, Nathaniel C. Crockett, Walter S. Borowski

EKU Faculty and Staff Scholarship

The Otter Creek watershed exhibits dissolved nutrient (ammonium, NH4; nitrate, NO3; phosphate, PO4) and Escherichia coli contamination that compromises its water quality. The watershed covers a substantial portion of Madison County and consists of Lake Reba, Dreaming Creek, and east and west forks, all of which enter the trunk of Otter Creek before flowing into the Kentucky River. Suspected contaminate sources include leaky sewage system pipes, runoff from pasture land, and septic system leachate. We collected 330 water samples on three occasions during summer 2014 to determine the extent and sources of contamination. Nutrients …


Microbial Iron Mats At The Mid-Atlantic Ridge And Evidence That Zetaproteobacteria May Be Restricted To Iron-Oxidizing Marine Systems, Jarrod J. Scott, John A. Breier, George W. Luther Iii, David Emerson Mar 2015

Microbial Iron Mats At The Mid-Atlantic Ridge And Evidence That Zetaproteobacteria May Be Restricted To Iron-Oxidizing Marine Systems, Jarrod J. Scott, John A. Breier, George W. Luther Iii, David Emerson

School of Earth, Environmental, & Marine Sciences Faculty Publications

Chemolithoautotrophic iron-oxidizing bacteria play an essential role in the global iron cycle. Thus far, the majority of marine iron-oxidizing bacteria have been identified as Zetaproteobacteria, a novel class within the phylum Proteobacteria. Marine iron-oxidizing microbial communities have been found associated with volcanically active seamounts, crustal spreading centers, and coastal waters. However, little is known about the presence and diversity of iron-oxidizing communities at hydrothermal systems along the slow crustal spreading center of the Mid-Atlantic Ridge. From October to November 2012, samples were collected from rust-colored mats at three well-known hydrothermal vent systems on the Mid-Atlantic Ridge (Rainbow, Trans-Atlantic Geotraverse, and …


Dissolved Fe And Al In The Upper 1000 M Of The Eastern Indian Ocean: A High‐Resolution Transect Along 95°E From The Antarctic Margin To The Bay Of Bengal, Maxime Grand, Christopher Measures, Mariko Hatta, William Hiscock, William Landing, Peter Morton, Clifton Buck, Pamela Barrett, Joseph Resing Mar 2015

Dissolved Fe And Al In The Upper 1000 M Of The Eastern Indian Ocean: A High‐Resolution Transect Along 95°E From The Antarctic Margin To The Bay Of Bengal, Maxime Grand, Christopher Measures, Mariko Hatta, William Hiscock, William Landing, Peter Morton, Clifton Buck, Pamela Barrett, Joseph Resing

Faculty Publications

A high‐resolution section of dissolved iron (dFe) and aluminum (dAl) was obtained along ~95°E in the upper 1000 m of the eastern Indian Ocean from the Antarctic margin (66°S) to the Bay of Bengal (18°N) during the U.S. Climate Variability and Predictability (CLIVAR) CO2 Repeat Hydrography I08S and I09N sections (February–April 2007). In the Southern Ocean, low concentrations of dAl (<1 n M) reflect the negligible dust inputs impacting the water masses subducted in the circumpolar domain. The low dAl concentrations characterizing the Southern Ocean terminate near 45°S, probably because of the advection of subtropical water masses that received dust and sedimentary inputs in their formation region. Our subsurface dFe data near the southern Kerguelen Plateau were significantly higher than historical observations in other Indian sectors of the Southern Ocean. We surmise that the offshore advection of dFe‐rich waters along the western flank of the southern Kerguelen plateau and enhanced vertical mixing could contribute to this elevated subsurface dFe inventory. Elevated subsurface particulate and dFe levels downstream of the northern Kerguelen Plateau may reflect long‐range lateral transport from the plateau's sediments and/or remineralization inputs. At the northern edge of the south Indian subtropical gyre, the deposition of Australian dust, possibly combined with the advection of dAl‐enriched waters from the Indonesian Throughflow, creates a region of elevated dAl in the upper 400 m but without a corresponding enrichment in dFe. In the northern Indian Ocean, the South Equatorial Current constitutes a remarkable biogeochemical front separating the oxygen‐rich and dFe‐poor subtropical gyre waters from the dFe‐rich and oxygen‐depleted waters of the northern Indian Ocean. By tracing the accumulation of macronutrients and dFe along the advective pathway of Indian Central Water, we show that the central waters of the northern Indian Ocean receive excess dFe in addition to that produced by remineralization inputs. The resuspension of shelf sediments and release of pore waters probably contribute to the elevated dFe and dAl levels observed below the highly stratified upper layers of the Bay of Bengal.


Dust Deposition In The Eastern Indian Ocean: The Ocean Perspective From Antarctica To The Bay Of Bengal, Maxime Grand, Christopher Measures, Mariko Hatta, William Hiscock, Clifton Buck, William Landing Mar 2015

Dust Deposition In The Eastern Indian Ocean: The Ocean Perspective From Antarctica To The Bay Of Bengal, Maxime Grand, Christopher Measures, Mariko Hatta, William Hiscock, Clifton Buck, William Landing

Faculty Publications

Atmospheric deposition is an important but still poorly constrained source of trace micronutrients to the open ocean because of the dearth of in situ measurements of total deposition (i.e., wet + dry deposition) in remote regions. In this work, we discuss the upper ocean distribution of dissolved Fe and Al in the eastern Indian Ocean along a 95°E meridional transect spanning the Antarctic margin to the Bay of Bengal. We use the mixed layer concentration of dissolved Al in conjunction with empirical data in a simple steady state model to produce 75 estimates of total dust deposition that we compare …


Rapid Imbibition Of Water In Fractures Within Unsaturated Sedimentary Rock, Chu-Lin Cheng, E. Perfect, B. Donnelly, H. Z. Bilheux, A. S. Tremsin, L. D. Mckay, V. H. Distefano, J. C. Cai, L. J. Santodonato Mar 2015

Rapid Imbibition Of Water In Fractures Within Unsaturated Sedimentary Rock, Chu-Lin Cheng, E. Perfect, B. Donnelly, H. Z. Bilheux, A. S. Tremsin, L. D. Mckay, V. H. Distefano, J. C. Cai, L. J. Santodonato

School of Earth, Environmental, & Marine Sciences Faculty Publications

The spontaneous imbibition of water and other liquids into gas-filled fractures in variably-saturated porous media is important in a variety of engineering and geological contexts. However, surprisingly few studies have investigated this phenomenon. We present a theoretical framework for predicting the 1-dimensional movement of water into air-filled fractures within a porous medium based on early-time capillary dynamics and spreading over the rough surfaces of fracture faces. The theory permits estimation of sorptivity values for the matrix and fracture zone, as well as a dispersion parameter which quantifies the extent of spreading of the wetting front. Quantitative data on spontaneous imbibition …


Hydroclimatic Shifts In Northeast Thailand During The Last Two Millennia — The Record Of Lake Pa Kho, Sakonvan Chawchai, Akkaneewut Chabangborn, Sherilyn C. Fritz, Minna Väliranta, Carl-Magnus Mörth, Maarten Blaauw, Paul J. Reimer, Paul J. Kusic, Ludvig Löwemark, Barbara Wohlfarth Mar 2015

Hydroclimatic Shifts In Northeast Thailand During The Last Two Millennia — The Record Of Lake Pa Kho, Sakonvan Chawchai, Akkaneewut Chabangborn, Sherilyn C. Fritz, Minna Väliranta, Carl-Magnus Mörth, Maarten Blaauw, Paul J. Reimer, Paul J. Kusic, Ludvig Löwemark, Barbara Wohlfarth

Department of Earth and Atmospheric Sciences: Faculty Publications

The Southeast Asian mainland is located in the central path of the Asian summer monsoon, a region where paleoclimatic data are still sparse. Here we present a multi-proxy (TOC, C/N, δ13C, biogenic silica, and XRF elemental data) study of a 1.5 m sediment/peat sequence from Lake Pa Kho, northeast Thailand, which is supported by 20 AMS 14C ages. Hydroclimatic reconstructions for Pa Kho suggest a strengthened summer monsoon between BC 170–AD 370, AD 800–960, and after AD 1450; and a weakening of the summer monsoon between AD 370–800, and AD 1300–1450. Increased run-off and a higher nutrient supply after AD …


Core Evolution Driven By Mantle Global Circulation, Peter Olson, Renaud Deguen, Maxwell L. Rudolph, Shijie Zhong Mar 2015

Core Evolution Driven By Mantle Global Circulation, Peter Olson, Renaud Deguen, Maxwell L. Rudolph, Shijie Zhong

Geology Faculty Publications and Presentations

Reconstructions of the Phanerozoic history of mantle global circulation that include past plate motions are used to constrain the thermochemical evolution of the core. According to our mantle global circulation models, the present-day global average heat flux at the core-mantle boundary lies in the range 80-90 mW.m-2, with peak-to-peak, long wavelength lateral variations up to 100 mW.m-2 associated with compositional and thermal heterogeneity in the D”-layer. For core thermal conductivity in the range k=100-130 W.m-1.K-1 we infer that the present-day outer core is thermally unstable beneath the high seismic velocity regions in the …