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- Caves and Karst (4)
- Geochemistry and Climatology (4)
- Hydrogeology (4)
- Biochar (2)
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- Climate change (2)
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- Lead isotope geochemistry sacramento river california gasoline emissions (2)
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- Megafauna (2)
- Norway (2)
- Tephra, lake sediments (2)
- Abstract (1)
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- Acid-base accounting (1)
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- Anoxia (1)
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- Armenia; Mining; Smelter; Lead; Residential soil and dust; Alaverdi (1)
- Bauxite refinery residue (1)
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Articles 1 - 30 of 37
Full-Text Articles in Physical Sciences and Mathematics
Impact Of Biochar Amendments On The Quality Of A Typical Midwestern Agricultural Soil, David A. Laird, Pierce Fleming, Dedrick D. Davis, Robert Horton, Baiqun Wang, Douglas L. Karlen
Impact Of Biochar Amendments On The Quality Of A Typical Midwestern Agricultural Soil, David A. Laird, Pierce Fleming, Dedrick D. Davis, Robert Horton, Baiqun Wang, Douglas L. Karlen
Douglas L Karlen
Biochar, a co-product of thermochemical conversion of lignocellulosic materials into advanced biofuels, may be used as a soil amendment to enhance the sustainability of biomass harvesting. We investigated the impact of biochar amendments (0, 5, 10, and 20 g-biochar kg− 1 soil) on the quality of a Clarion soil (Mesic Typic Hapludolls), collected (0–15 cm) in Boone County, Iowa. Repacked soil columns were incubated for 500 days at 25 °C and 80% relative humidity. On week 12, 5 g of dried and ground swine manure was incorporated into the upper 3 cm of soil for half of the columns. Once …
Biochar Impact On Nutrient Leaching From A Midwestern Agricultural Soil, David Laird, Pierce Flemming, Baiqun Wang, Robert Horton, Douglas Karlen
Biochar Impact On Nutrient Leaching From A Midwestern Agricultural Soil, David Laird, Pierce Flemming, Baiqun Wang, Robert Horton, Douglas Karlen
Douglas L Karlen
Application of biochar to highly weathered tropical soils has been shown to enhance soil quality and decrease leaching of nutrients. Little, however, is known about the effects of biochar applications on temperate region soils. Our objective was to quantify the impact of biochar on leaching of plant nutrients following application of swine manure to a typical Midwestern agricultural soil. Repacked soil columns containing 0, 5, 10, and 20 g-biochar kg− 1-soil, with and without 5 g kg− 1 of dried swine manure were leached weekly for 45 weeks. Measurements showed a significant decrease in the total amount of N, P, …
Belowground Rhizomes In Paleosols: The Hidden Half Of An Early Devonian Vascular Plant, Jinzhuang Xue, Zhenzhen Deng, Pu Huang, Kangjun Huang, Michael J. Benton, Ying Cui
Belowground Rhizomes In Paleosols: The Hidden Half Of An Early Devonian Vascular Plant, Jinzhuang Xue, Zhenzhen Deng, Pu Huang, Kangjun Huang, Michael J. Benton, Ying Cui
Ying Cui
The colonization of terrestrial environments by rooted vascular plants had far-reaching impacts on the Earth system. However, the belowground structures of early vascular plants are rarely documented, and thus the plant−soil interactions in early terrestrial ecosystems are poorly understood. Here we report the earliest rooted paleosols (fossil soils) in Asia from Early Devonian deposits of Yunnan, China. Plant traces are extensive within the soil and occur as complex network-like structures, which are interpreted as representing long-lived, belowground rhizomes of the basal lycopsid Drepanophycus. The rhizomes produced large clones and helped the plant survive frequent sediment burial in well-drained soils …
Multivariate Spectral Analysis Of Crism Data To Characterize The Composition Of Mawrth Vallis, Melissa Luna
Multivariate Spectral Analysis Of Crism Data To Characterize The Composition Of Mawrth Vallis, Melissa Luna
Melissa Luna
No abstract provided.
Data-Driven Diagnostics Of Terrestrial Carbon Dynamics Over North America, Jingfeng Xiao, Scott V. Ollinger, Steve Frolking, George Hurtt, David Y. Hollinger, Kenneth J. Davis, Yude Pan, Xiaoyang Zhang, Feng Deng, Jiquan Chen, Dennis D. Baldocchi, Beverly E. Law, M. Altaf Arain, Ankur R. Desai, Andrew D. Richardson, Ge Sun, Brian Amiro, Hank Margolis, Lianhong Gu, Russell L. Scott, Peter D. Blanken, Andrew E. Suyker
Data-Driven Diagnostics Of Terrestrial Carbon Dynamics Over North America, Jingfeng Xiao, Scott V. Ollinger, Steve Frolking, George Hurtt, David Y. Hollinger, Kenneth J. Davis, Yude Pan, Xiaoyang Zhang, Feng Deng, Jiquan Chen, Dennis D. Baldocchi, Beverly E. Law, M. Altaf Arain, Ankur R. Desai, Andrew D. Richardson, Ge Sun, Brian Amiro, Hank Margolis, Lianhong Gu, Russell L. Scott, Peter D. Blanken, Andrew E. Suyker
Xiaoyang Zhang
The exchange of carbon dioxide is a key measure of ecosystem metabolism and a critical intersection between the terrestrial biosphere and the Earth’s climate. Despite the general agreement that the terrestrial ecosystems in North America provide a sizeable carbon sink, the size and distribution of the sink remain uncertain. We use a data-driven approach to upscale eddy covariance flux observations from towers to the continental scale by integrating flux observations, meteorology, stand age,aboveground biomass, and a proxy for canopy nitrogen concentrations from AmeriFlux and Fluxnet-Canada Research Network as well as a variety of satellite data streams from the MODIS sensors. …
Lower Lakes Carbon Project: The Aquatic Vegetation Contribution To Carbon Pools, Leigh A. Sullivan, Nicholas J. Ward, Richard T. Bush, Alicia Hidden, Diane M. Fyfe, Michelle Bush, Crystal A. Maher
Lower Lakes Carbon Project: The Aquatic Vegetation Contribution To Carbon Pools, Leigh A. Sullivan, Nicholas J. Ward, Richard T. Bush, Alicia Hidden, Diane M. Fyfe, Michelle Bush, Crystal A. Maher
Adjunct Professor Richard T Bush
No abstract provided.
Lower Lakes Carbon Project: The Aquatic Vegetation Contribution To Carbon Pools, Leigh A. Sullivan, Nicholas J. Ward, Richard T. Bush, Alicia Hidden, Diane M. Fyfe, Michelle Bush, Crystal A. Maher
Lower Lakes Carbon Project: The Aquatic Vegetation Contribution To Carbon Pools, Leigh A. Sullivan, Nicholas J. Ward, Richard T. Bush, Alicia Hidden, Diane M. Fyfe, Michelle Bush, Crystal A. Maher
Dr Nicholas J Ward
No abstract provided.
Nitrates In Karst Systems: Comparing Impacted Systems To A Relatively Unimpacted System, Julie C. Angel, Eric Wade Peterson
Nitrates In Karst Systems: Comparing Impacted Systems To A Relatively Unimpacted System, Julie C. Angel, Eric Wade Peterson
Eric Wade Peterson
Karst aquifers are highly susceptible to contamination because of the connection with surface water. Nitrate contamination is common; with most karst aquifers exhibiting some degree of impact. This work assesses the potential impacts of anthropogenic activities on the Horn Hollow Valley (HHV) in Carter County Kentucky. HHV is a karst aquifer system that appears to be minimally impacted by nitrate and chloride contamination. Sampling of the HHV area was conducted from June 2005 to November 2006. Nitrate as nitrogen (NO3-N) concentrations were between 0.13 to 1.54 mg/L; chloride concentrations ranged from 1.43 to 66.3 mg/L. Impact from anthropogenic sources are …
Microbe-Mineral Relationships And Biogenic Mineral Transformations In Actively Venting Deep-Sea Hydrothermal Sulfide Chimneys, Tzihsuan J. Lin
Microbe-Mineral Relationships And Biogenic Mineral Transformations In Actively Venting Deep-Sea Hydrothermal Sulfide Chimneys, Tzihsuan J. Lin
TZIHSUAN J LIN
This dissertation uses a combination of microbiology, mineralogy, and geochemistry to understand dissimilatory iron reduction in hyperthermophilic archaea and the role and potential impact of these and other vent microorganisms within active deep-sea hydrothermal vent chimneys. The central objective of the dissertation is to determine if mineral composition and chimney type are among the primary determinants of microbial community composition and hyperthermophilic, dissimilatory iron reducer growth, in addition to other environmental factors such as nutrient availability, temperature, pH, and chlorinity. This is done using samples and organisms collected from the Endeavour Segment of the Juan de Fuca Ridge in the …
Locating Cryptotephra In Sediments Using Fluid Imaging Technology, Robert D'Anjou, Nicholas L. Balascio, Raymond S. Bradley
Locating Cryptotephra In Sediments Using Fluid Imaging Technology, Robert D'Anjou, Nicholas L. Balascio, Raymond S. Bradley
Raymond S Bradley
We report a new approach to locate and quantify cryptotephra in sedimentary archives using a continuously-imaging Flow Cytometer and Microscope (FlowCAM_). The FlowCAM rapidly photographs particles flowing in suspension past a microscope lens and performs semi-automated analysis of particle images. It has had primarily biological applications, although the potential sedimentological applications are numerous. Here we test the ability of this instrument to image irregularly shaped, vesicular glass shards and to screen sediment samples for the presence of cryptotephra. First, reference samples of basalt and rhyolite tephra (sieved <63>microns) were analyzed with the FlowCAM, demonstrating the ability of the instrument to …
Isotopes Of Carbon In A Karst Aquifer Of The Cumberland Platea Of Kentucky , Usa, Lee J. Florea
Isotopes Of Carbon In A Karst Aquifer Of The Cumberland Platea Of Kentucky , Usa, Lee J. Florea
Lee J Florea, PhD, P.G.
In this study, the concentration and isotopic composition of dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) are measured in the karst groundwater of the Otter Creek watershed of the Cumberland Plateau of Kentucky, USA. Comparisons among these data and with the geochemistry of carbonate and gypsum equilibrium reactions reveal that DOC concentration is inversely related to discharge, multiple reaction pathways provide DIC with isotopic enrichment that may be directly related to mineral saturation, and oxidation of reduced sulfur is possible for dissolution. DOC is derived from C3 vegetation with an average δ13CDOC of ‒27‰. DIC in groundwater is …
Preliminary Summary Of Water Resource Investigations During 2012 At Timpanogos Cave National Monument, Utah, Lee J. Florea, Chelsie R. Dugan, Camille Mckinney
Preliminary Summary Of Water Resource Investigations During 2012 At Timpanogos Cave National Monument, Utah, Lee J. Florea, Chelsie R. Dugan, Camille Mckinney
Lee J Florea, PhD, P.G.
This manuscript considers the hydrology and geochemistry of water resources within Timpanogos Cave National Monument in American Fork, Utah. In particular, data are presented for five cave pools within the Monument and the American Fork River that flows through the Monument. Two independent dye trace attempts in this study have not established a connection between the surface near the canyon rim at the south border of the Monument and the cave pools or the river. Ion chemistry of the pools reveals elevated sulfate concentrations. Analysis of sulfate and other reaction products suggests the possibility of combined carbonic and sulfuric acids …
Sulfide Oxidation In Some Acid Sulfate Soil Materials, Nicholas John Ward
Sulfide Oxidation In Some Acid Sulfate Soil Materials, Nicholas John Ward
Dr Nicholas J Ward
This thesis examines sulfide oxidation in 4 physically and mineralogically diverse acid sulfate soil (ASS) materials collected from coastal floodplain sites in north-eastern New South Wales. The aim of this study is to gain further understanding of the process of sulfide oxidation in ASS materials, which will allow improved and more effective management strategies to be applied to these materials. The process of sulfide oxidation was examined using laboratory incubation experiments. The oxidation of pyrite was the primary cause of initial acidification of the ASS materials studied. Although the acid volatile sulfur fraction increased in concentration by an order of …
Investigations Into The Potential For Hypogene Speleogenesis In The Cumberland Plateau Of Southeast Kentucky, U.S.A., Lee J. Florea
Investigations Into The Potential For Hypogene Speleogenesis In The Cumberland Plateau Of Southeast Kentucky, U.S.A., Lee J. Florea
Lee J Florea, PhD, P.G.
This manuscript offers preliminary geochemical evidence that investigates the potential for hypogene speleogenesis in the Cumberland Plateau of southeastern Kentucky, U.S.A. The region was traditionally considered a classic example of epigenic karst, but new insights have uncovered tantalizing observations that suggest alternatives to simple carbonic acid speleogenesis. Such first-order observations have included natural petroleum seeps at the surface and in caves, occasional cave morphologies consistent with action of hypogene fluids, and prolific gypsum within cave passages. To this point, geochemical data from caves and springs verify carbonic acid as the primary dissolutional agent; however, these same analyses cannot rule out …
Biomarker And Sedimentological Investigations Of Mis 8 Through Mis 12 From Lake El'gygytgyn, Ne Arctic Russia, Jeremy H. Wei, Julie Brigham-Grette, David Finkelstein, Isla S. Castañeda
Biomarker And Sedimentological Investigations Of Mis 8 Through Mis 12 From Lake El'gygytgyn, Ne Arctic Russia, Jeremy H. Wei, Julie Brigham-Grette, David Finkelstein, Isla S. Castañeda
Jeremy H Wei
Multiple proxy analysis of lake sediment records are crucial for understanding changes in environmental and climate conditions over historical and geological time. Most recently, the use of biomarker proxies coupled with sedimentological investigations provides a new approach for gaining insight into the lake processes that capture information about past climate change. This approach is applied here to better understand the paleoclimate record from Lake El’gygytgyn in Western Beringia. Multiple organic geochemical compound concentrations were measure as proxies for both aquatic and terrestrial biological productivity. Measurements of n-alkane (plant leaf waxes) as well as concentrations of the compounds arborinol (marker for …
The Effects Of Evapotranspiration Upon Recharge Using The Stable Isotopes Of Oxygen And Hydrogen In The Carbonate Aquifers Of The Cumberland Plateau In Southeast Kentucky, Lee J. Florea
Lee J Florea, PhD, P.G.
In this brief manuscript, we consider the variation of the stable isotopes of oxygen, δ18O, and hydrogen, δ2H, in samples collected during 2010 and 2011 from precipitation and shallow groundwater along the Cumberland Plateau of southeast Kentucky. These data from the 1,900-ha Redmond Creek karst aquifer lend insight into the source and timing of recharge to shallow groundwater in the epigenic karst of the U.S midcontinent. Specifically, we find that only 43% of precipitation remains as potential recharge after accounting for evapotranspiration, and 85% of this potential recharge occurs during only four two-week sampling periods. The isotopic composition of precipitation …
Thermal Fluid And Fault Interactions At The Intersection Of Two Faults, Agua Caliente, California, Rebekah Wood, James Evans
Thermal Fluid And Fault Interactions At The Intersection Of Two Faults, Agua Caliente, California, Rebekah Wood, James Evans
Rebekah Wood
Agua Caliente Springs lies at a unique intersection between the NNW-trending Elsinore fault and the 40° northeast-dipping, likely inactive West Salton detachment fault; it provides an opportunity to study damage zone geometry, fault behavior in crystalline rocks, a left-stepover, microseismicity, and the influence of thermal fluids on rock deformation. The Elsinore fault bounds the northwestern flank of the Tierra Blanca Mountains with strike-slip and normal motion; the detachment fault wraps around the northernmost portion of the mountains. Damage along the Elsinore ranges in thickness from a narrow slip plane to > 100 m along the eastern flank of the Tierra Blanca …
Iron Geochemical Zonation In A Tidally Inundated Acid Sulfate Soil Wetland, Scott G. Johnston, Annabelle F. Keene, Richard T. Bush, Edward D. Burton, Leigh A. Sullivan, Lloyd S. Isaacson, Angus E. Mcelnea, Colin R. Ahern, C Douglas Smith, Bernard Powell
Iron Geochemical Zonation In A Tidally Inundated Acid Sulfate Soil Wetland, Scott G. Johnston, Annabelle F. Keene, Richard T. Bush, Edward D. Burton, Leigh A. Sullivan, Lloyd S. Isaacson, Angus E. Mcelnea, Colin R. Ahern, C Douglas Smith, Bernard Powell
Professor Edward D Burton
Tidal inundation is a new technique for remediating coastal acid sulfate soils (CASS). Here, we examine the effects of this technique on the geochemical zonation and cycling of Fe across a tidally inundated CASS toposequence, by investigating toposequence hydrology, in situ porewater geochemistry, solid-phase Fe fractions and Fe mineralogy. Interactions between topography and tides exerted a fundamental hydrological control on the geochemical zonation, redistribution and subsequent mineralogical transformations of Fe within the landscape. Reductive dissolution of Fe(III) minerals, including jarosite (KFe3(SO4)2(OH)6), resulted in elevated concentrations of porewater Fe2+ (> 30 mmol L−1) in former sulfuric horizons in the upper-intertidal zone. …
Distal Tephra Found In A Viking Boathouse: The Potential For Tephrochronology In Reconstructing The Iron Age In Norway, Nicholas L. Balascio, Stephen Wickler, L E. Narmo, Raymond S. Bradley
Distal Tephra Found In A Viking Boathouse: The Potential For Tephrochronology In Reconstructing The Iron Age In Norway, Nicholas L. Balascio, Stephen Wickler, L E. Narmo, Raymond S. Bradley
Raymond S Bradley
Distal tephra deposits from Icelandic volcanic eruptions have been found in Norway and can be used to precisely date a variety of sedimentary environments. Tephrochronology has not yet been applied to archaeological investigations in Norway because tephra are generally not found as visible layers, but are present as very low concentrations of glass shards (i.e. cryptotephra). In this study, we present results from the analysis of cryptotephras found in an Iron Age boathouse in northern Norway. The boathouse was associated with the chieftain center at Borg on Vestvågøy in the Lofoten Islands. In 2003, a trench was excavated and the …
A Multi-Proxy Approach To Assessing Isolation Basin Stratigraphy From The Lofoten Islands, Norway, Nicholas L. Balascio, Zhaohui Zhang, Raymond S. Bradley, Bianca B. Perren, Svein-Olaf Dahl, Jostein Bakke
A Multi-Proxy Approach To Assessing Isolation Basin Stratigraphy From The Lofoten Islands, Norway, Nicholas L. Balascio, Zhaohui Zhang, Raymond S. Bradley, Bianca B. Perren, Svein-Olaf Dahl, Jostein Bakke
Raymond S Bradley
This study takes a comprehensive approach to characterizing the isolation sequence of Heimerdalsvatnet, a coastal lake in the Lofoten Islands, northern Norway. We use established methods and explore new techniques to assess changes in marine influence. Bathymetric and sub-bottom profiles were acquired to examine basin-wide sedimentation and a 5.8 m sediment core spanning the last 7800 cal yr BP was analyzed. We measured magnetic susceptibility, bulk organic matter properties, molecular biomarkers, diatom assemblages, and elemental profiles acquired by scanning X-ray fluorescence. These characteristics of the sediment reflect detailed changes in salinity and water column conditions as the lake was progressively …
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 …
Presence Of A Long-Term Lithospheric Thermal Anomaly: Evidence From Apatite Fission-Track Analysis In Northern New England, Mary K. Roden-Tice, David P. West Jr., Jaime K. Potter, Sarah M. Raymond, Jenny L. Winch
Presence Of A Long-Term Lithospheric Thermal Anomaly: Evidence From Apatite Fission-Track Analysis In Northern New England, Mary K. Roden-Tice, David P. West Jr., Jaime K. Potter, Sarah M. Raymond, Jenny L. Winch
Mary K. Roden-Tice
Apatite fission-track (AFT) ages from 56 samples of Paleozoic and Mesozoic crystalline rocks in New Hampshire, northeastern Vermont, and western Maine range from 70 to 140 Ma and reflect widespread Early to Late Cretaceous cooling. The regional AFT age distributions determined in this study suggest that reactivation of preexisting orogen-parallel faults and the presence of a long-lived thermal anomaly in the lithospheric mantle controlled the late unroofing history of this part of the northern Appalachians. A northeast-trending zone of young, dominantly Late Cretaceous AFT ages (70-118 Ma) extends from southwestern New Hampshire through the central White Mountain region and continues …
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 …
Plio-Quaternary Exhumation History Of The Central Nepalese Himalaya: 1. Apatite And Zircon Fission Track And Apatite [U-Th]/He Analyses, Ann Blythe, D Burbank, A Carter, K Schmidt, J Putkonen
Plio-Quaternary Exhumation History Of The Central Nepalese Himalaya: 1. Apatite And Zircon Fission Track And Apatite [U-Th]/He Analyses, Ann Blythe, D Burbank, A Carter, K Schmidt, J Putkonen
Ann Blythe
No abstract provided.
Trace Element Chemistry Of Zircons From Oceanic Crust: A Method For Distinguishing Detrital Zircon Provenance, C B. Grimes, B E. John, P B. Kelemen, F K. Mazdab, J L. Wooden, M J. Cheadle, K Hanghoj, J J. Schwartz
Trace Element Chemistry Of Zircons From Oceanic Crust: A Method For Distinguishing Detrital Zircon Provenance, C B. Grimes, B E. John, P B. Kelemen, F K. Mazdab, J L. Wooden, M J. Cheadle, K Hanghoj, J J. Schwartz
Barbara John
We present newly acquired trace element compositions for more than 300 zircon grains in 36 gabbros formed at the slow-spreading Mid-Atlantic and Southwest Indian Ridges. Rare earth element patterns for zircon from modern oceanic crust completely overlap with those for zircon crystallized in continental granitoids. However, plots of U versus Yb and U/Yb versus Hf or Y discriminate zircons crystallized in oceanic crust from continental zircon, and provide a relatively robust method for distinguishing zircons from these environments. Approximately 80% of the modern ocean crust zircons are distinct from the fi eld defi ned by more than 1700 continental zircons …
In The Heat Of The Law, It's Not Just Steam: Geothermal Resources And The Impact On Thermophile Biodiversity, Donald J. Kochan, Tiffany Grant
In The Heat Of The Law, It's Not Just Steam: Geothermal Resources And The Impact On Thermophile Biodiversity, Donald J. Kochan, Tiffany Grant
Donald J. Kochan
Significant research has been conducted into the utilization of geothermal resources as a ‘green’ energy source. However, minimal research has been conducted into geothermal resource utilization and depletion impacts on thermophile biodiversity. Thermophiles are organisms which have adapted over millions of year to extreme temperature and chemical compositions and exist in hot springs and other geothermal resources. Their ability to withstand high temperatures makes them invaluable to scientific and medical research. Current federal and California case law classify geothermal resources as a mineral, not a water resource. Acquisition of rights to develop a geothermal resource owned or reserved by the …
Regional-Scale Mid-Jurassic To Late Cretaceous Unroofing From The Adirondack Mountains Through Central New England Based On Apatite Fission-Track And (U-Th)/He Thermochronology, Mary K. Roden-Tice, Steven J. Tice
Regional-Scale Mid-Jurassic To Late Cretaceous Unroofing From The Adirondack Mountains Through Central New England Based On Apatite Fission-Track And (U-Th)/He Thermochronology, Mary K. Roden-Tice, Steven J. Tice
Mary K. Roden-Tice
Apatite fission-track (AFT) ages of 178 to 70 Ma for 108 samples from the Adirondack Mountains and eastern New York State, Vermont, western Massachusetts and Connecticut, and western New Hampshire indicate that widespread unroofing occurred throughout the region during the Middle Jurassic to Late Cretaceous. Additionally, (U-Th)/He ages of 167 to 85 Ma were determined on nine of those samples and support cooling rates of 1.8°-2.2°C/m.yr. from 100° to 65°C during the Middle Jurassic to Late Cretaceous. Assuming a geothermal gradient of 25°C/km, unroofing rates for the region were estimated to be, on average, ∼0.07-0.08 km/m.yr. The AFT age discontinuities …
Long-Range Downstream Effects Of Urban Runoff And Acid Mine Drainage In The Debed River, Armenia: Insights From Lead Isotope Modeling, Robert Kurkjian, Charles Dunlap, A. Flegal
Long-Range Downstream Effects Of Urban Runoff And Acid Mine Drainage In The Debed River, Armenia: Insights From Lead Isotope Modeling, Robert Kurkjian, Charles Dunlap, A. Flegal
Charles Dunlap
Lead concentrations and isotopic compositions measured along 80 km of the Debed River in the Republic of Armenia provide new insights into the geochemical and physical controls on riparian Pb transport by allowing comparison of the long-range, downstream impacts of acid mine drainage with runoff from an industrialized city. The modern background Pb concentration in Armenian surface waters is estimated to be ~0.01 lg/L, based on analyses of remote alpine rivers in Armenia. The lead concentration in the Debed River is 8 µg/L (800 times background) after passing through Vanadzor, the second largest industrial city in Armenia; it then decreases …
Lead In Residential Soil And Dust In A Mining And Smelting District In Northern Armenia: A Pilot Study, Varduhi Petrosyan, Anna Orlova, Charles E. Dunlap, Emil Babayan, Mark Farfel, Margrit Von Braun
Lead In Residential Soil And Dust In A Mining And Smelting District In Northern Armenia: A Pilot Study, Varduhi Petrosyan, Anna Orlova, Charles E. Dunlap, Emil Babayan, Mark Farfel, Margrit Von Braun
Charles Dunlap
This pilot study of sources of lead exposure in residential settings was conducted in a mining and smelting district in northern Armenia. Samples of exterior soil and dust and interior house dust were collected in and around apartment buildings in Alaverdi where the country’s largest polymetallic smelter is located, and in nearby mining towns of Aghtala and Shamlugh. The NITON XL- 723 Multi-Element XRF analyzer was used for lead testing. Lead levels in samples from Alaverdi were higher than those in Shamlugh and Aghtala. In all three towns, the highest lead levels were found in loose exterior dust samples, and …
Preliminary Investigations Of Seasonal Changes In The Geochemical Evolution Of The Logdson River, Mammoth Cave, Kentucky, Chris Groves, Darlene M. Anthony, Joe Meiman
Preliminary Investigations Of Seasonal Changes In The Geochemical Evolution Of The Logdson River, Mammoth Cave, Kentucky, Chris Groves, Darlene M. Anthony, Joe Meiman
Chris Groves
Many geochemical studies have been made of karst waters worldwide. Most data that provide the framework for our current understanding of the evolution of karst waters have come from sampling at discrete times and locations, such as springs or wells. Relatively few studies have been made of the geochemical evolution of groundwater as it moves through an open flow system. This paper addresses the seasonal changes in the geochemistry of the Logsdon River conduit as it passes through nearly 10km of the carbonate aquifer of south-central Kentucky . The most important control on the ability of groundwaters to dissolve limestone …