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

Geology Commons™

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

2022

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 3061 - 3090 of 5201

Full-Text Articles in Geology

Effects Of Small-Scale Mining Activities On Fisheries And Livelihoods In The Birim River In Atiwa District, Eastern Region Of Ghana, Elliot Haruna Alhassan, Samuel Opoku Dandi, Sandra Akugpoka Atindana Sep 2022

Effects Of Small-Scale Mining Activities On Fisheries And Livelihoods In The Birim River In Atiwa District, Eastern Region Of Ghana, Elliot Haruna Alhassan, Samuel Opoku Dandi, Sandra Akugpoka Atindana

Tanzania Journal of Science

The socioeconomic importance of small-scale mining in Ghana is of great interest to the country. It provides employment, supports the livelihood of poor rural areas, and also contributes to national income. Despite all these importance, it has a great influence on the surroundings, with surface and groundwater bodies being the most affected. The study was conducted to determine the effects of small-scale mining activities on fisheries and livelihoods along the Birim River in Atiwa District of Ghana, and also, to ascertain the nature of mining in the catchment and the current status of fisheries in the river. Data were collected …

Go to article

Evaluation Of Enzymatic Activity During Growth Of Pleurotus Hk 37 On Saba Comorensis Exocarp, Isse I. Molobele, Rose J. Masalu, Prosper R. Mosha, Cyprian B. Mpinda Sep 2022

Evaluation Of Enzymatic Activity During Growth Of Pleurotus Hk 37 On Saba Comorensis Exocarp, Isse I. Molobele, Rose J. Masalu, Prosper R. Mosha, Cyprian B. Mpinda

Tanzania Journal of Science

Mushrooms degrade lignocellulosic biomass by releasing lignolytic and hydrolytic enzymes which convert lignocellulosic material into soluble and low molecular weight compounds which are then absorbed as nutrients. In the present study, enzymatic activities of Pleurotus HK 37 during growth on Saba comorensis exocarps were evaluated. It was observed that, Pleurotus HK 37 has ability to produce lignolytic enzyme (Laccase) and hydrolytic enzymes (Carboxymethyl cellulase, xylanase and filterpaperase). Maximum laccase activity of 3.33 ± 0 UmL-1 was observed during colonization period and the activity dropped during fruitification phase. Similar to hydrolytic enzymes, the activity was observed during colonization period and decreased …

Go to article

Drivers Of Pb, Sb And As Release From Spent Gunshot In Wetlands: Enhancement By Organic Matter And Native Microorganisms, Anna Potysz, Łukasz J. Binkowski, Jakub Kierczak, Barnett A. Rattner Sep 2022

Drivers Of Pb, Sb And As Release From Spent Gunshot In Wetlands: Enhancement By Organic Matter And Native Microorganisms, Anna Potysz, Łukasz J. Binkowski, Jakub Kierczak, Barnett A. Rattner

United States Geological Survey: Staff Publications

In many countries the use of lead-based ammunition is prevalent, and results in exposure and poisoning of waterfowl and other species of birds. In waterfowl hunting areas large quantities of spent shot may be deposited in wetland and terrestrial habitats. These pellets can undergo transformations, which are influenced by various abiotic and biotic factors. In addition to lead (Pb), other elements like antimony (Sb) and arsenic (As) can be leached from Pb shot into the environment. In vitro simulations that included organic matter and microorganisms were utilized to examine elemental leaching from gunshot. We found that leaching efficiency was the …

Go to article

Mgrre_Thinsections_05_A_35, Mgrre Sep 2022

Mgrre_Thinsections_05_A_35, Mgrre

Thin Sections

No abstract provided.

Go to article

Limits To Coseismic Landslides Triggered By Cascadia Subduction Zone Earthquakes, Alex R.R. Grant, William T. Struble, Sean R. Lahusen Sep 2022

Limits To Coseismic Landslides Triggered By Cascadia Subduction Zone Earthquakes, Alex R.R. Grant, William T. Struble, Sean R. Lahusen

United States Geological Survey: Staff Publications

Landslides are a significant hazard and dominant feature throughout the landscape of the Pacific Northwest. However, the hazard and risk posed by coseismic landslides triggered by great Cascadia Subduction Zone (CSZ) earthquakes is highly uncertain due to a lack of local and global data. Despite a wealth of other geologic evidence for past earthquakes on the Cascadia Subduction Zone, no landslides have been definitively linked to such earthquakes, even in areas otherwise highly susceptible to failure. While shallow landslides may not leave a lasting topographical signature in the landscape, there are thousands of deep-seated landslides in Cascadia, and these deposits …

Go to article

Mgrre_Thinsections_05_A_34, Mgrre Sep 2022

Mgrre_Thinsections_05_A_34, Mgrre

Thin Sections

No abstract provided.

Go to article

Very High Middle Miocene Surface Productivity On The U.S. Mid-Atlantic Shelf Amid Glacioeustatic Sea Level Variability, Marci M. Robinson, Harry J. Dowsett, Timothy D. Herbert Sep 2022

Very High Middle Miocene Surface Productivity On The U.S. Mid-Atlantic Shelf Amid Glacioeustatic Sea Level Variability, Marci M. Robinson, Harry J. Dowsett, Timothy D. Herbert

United States Geological Survey: Staff Publications

The Miocene Climatic Optimum (MCO) provides important insights into how the climate system operates under elevated temperatures and atmospheric CO2 levels. Few western North Atlantic paleotemperature or paleoecological records exist from the MCO, despite their importance for understanding both regional and global climate dynamics. Here we present quantitative MCO paleoecological data from the western North Atlantic, specifically from the Baltimore Gas & Electric (BG&E) marine sediment core from southern Maryland, USA. We examine alkenones and planktic foraminifera and document the first sea surface temperature (SST) and productivity estimates for the MCO and the Middle Miocene Climate Transition (MMCT) from …

Go to article

Discovering Hidden Geothermal Signatures Using Non-Negative Matrix Factorization With Customized K-Means Clustering, V. V. Vesselinov, B. Ahmmed, M. K. Mudunuru, J. D. Pepin, E. R. Burns, D. L. Siler, S. Karra, R. S. Middleton Sep 2022

Discovering Hidden Geothermal Signatures Using Non-Negative Matrix Factorization With Customized K-Means Clustering, V. V. Vesselinov, B. Ahmmed, M. K. Mudunuru, J. D. Pepin, E. R. Burns, D. L. Siler, S. Karra, R. S. Middleton

United States Geological Survey: Staff Publications

Discovery of hidden geothermal resources is challenging. It requires the mining of large datasets with diverse data attributes representing subsurface hydrogeological and geothermal conditions. The commonly used play fairway analysis approach typically incorporates subject-matter expertise to analyze regional data to estimate geothermal characteristics and favorability. We demonstrate an alternative approach based on machine learning (ML) to process a geothermal dataset from southwest New Mexico (SWNM). The study region includes low- and medium-temperature hydrothermal systems. Several of these systems are not well characterized because of insufficient existing data and limited past explorative work. This study discovers hidden patterns and relations in …

Go to article

Neural Net Detection Of Seismic Features Related To Gas Hydrates And Free Gas Accumulations On The Northern U.S. Atlantic Margin, Urmi Majumdar, Nathaniel C. Miller, Carolyn D. Ruppel Sep 2022

Neural Net Detection Of Seismic Features Related To Gas Hydrates And Free Gas Accumulations On The Northern U.S. Atlantic Margin, Urmi Majumdar, Nathaniel C. Miller, Carolyn D. Ruppel

United States Geological Survey: Staff Publications

Bottom-simulating reflections (BSRs) that sometimes mark the base of the gas hydrate stability zone in marine sediments are often identified based on the reverse polarity reflections that cut across stratigraphic layering in seismic amplitude data. On the northern U.S. Atlantic margin (USAM) between Cape Hatteras and Hudson Canyon, legacy seismic data have revealed pronounced BSRs south of the deepwater extension of Hudson Canyon and more subtle ones from offshore Delaware south to Cape Hatteras, where the reflections sometimes follow stratigraphic layering. Using high-resolution seismic data acquired during the 2018 Mid-Atlantic Resource Imaging Experiment and a supervised neural net, we identify …

Go to article

Mgrre_Thinsections_05_A_33, Mgrre Sep 2022

Mgrre_Thinsections_05_A_33, Mgrre

Thin Sections

No abstract provided.

Go to article

Establishment Of Invasive Black Carp (Mylopharyngodon Piceus) In The Mississippi River Basin: Identifying Sources And Year Classes Contributing To Recruitment, Gregory W. Whitledge, Patrick T. Kroboth, Duane C. Chapman, Quinton E. Phelps, Wes Sleeper, Jennifer Bailey, Jill A. Jenkins Sep 2022

Establishment Of Invasive Black Carp (Mylopharyngodon Piceus) In The Mississippi River Basin: Identifying Sources And Year Classes Contributing To Recruitment, Gregory W. Whitledge, Patrick T. Kroboth, Duane C. Chapman, Quinton E. Phelps, Wes Sleeper, Jennifer Bailey, Jill A. Jenkins

United States Geological Survey: Staff Publications

Black Carp (Mylopharyngodon piceus) was imported to the USA to control aquaculture pond snails. This species has escaped captivity and occurs in parts of the Mississippi River, several tributaries, and floodplain lakes, which is concerning due to potential competition with native fishes and predation on native mussels, many of which are imperiled. However, Black Carp captures have primarily been incidental by commercial fishers, and evidence of reproduction in the wild is limited. The objectives of this study were to assess relative abundance of aquaculture- origin and wild Black Carp using ploidy and otolith stable isotope analysis, identify spatial …

Go to article

Mgrre_Thinsections_05_A_32, Mgrre Sep 2022

Mgrre_Thinsections_05_A_32, Mgrre

Thin Sections

No abstract provided.

Go to article

Multi-Omics Responses In Tree Swallow (Tachycineta Bicolor) Nestlings From The Maumee Area Of Concern, Maumee River, Ohio, Chi Yen Tseng, Christine M. Custer, Thomas W. Custer, Paul M. Dummer, Natalie Karouna-Renier, Cole W. Matson Sep 2022

Multi-Omics Responses In Tree Swallow (Tachycineta Bicolor) Nestlings From The Maumee Area Of Concern, Maumee River, Ohio, Chi Yen Tseng, Christine M. Custer, Thomas W. Custer, Paul M. Dummer, Natalie Karouna-Renier, Cole W. Matson

United States Geological Survey: Staff Publications

A multi-omics approach was utilized to identify altered biological responses and functions, and to prioritize contaminants to assess the risks of chemical mixtures in the Maumee Area of Concern (AOC), Maumee River, OH, USA. The Maumee AOC is designated by the United States Environmental Protection Agency as having significant beneficial use impairments, including degradation of fish and wildlife populations, bird or animal deformities or reproduction problems, and loss of fish and wildlife habitat. Tree swallow (Tachycineta bicolor) nestlings were collected at five sites along the Maumee River, which included wastewater treatment plants (WWTPs) and industrial land-use sites. Polychlorinated …

Go to article

Mgrre_Thinsections_05_A_31, Mgrre Sep 2022

Mgrre_Thinsections_05_A_31, Mgrre

Thin Sections

No abstract provided.

Go to article

A Systematic Review And Meta-Analysis Of The Direct Effects Of Nutrients On Corals, Eileen M. Nalley, Lillian J. Tuttle, Emily E. Conklin, Alexandria L. Barkman, Devynn M. Wulstein, Madeline C. Schmidbauer, Megan J. Donahue Sep 2022

A Systematic Review And Meta-Analysis Of The Direct Effects Of Nutrients On Corals, Eileen M. Nalley, Lillian J. Tuttle, Emily E. Conklin, Alexandria L. Barkman, Devynn M. Wulstein, Madeline C. Schmidbauer, Megan J. Donahue

United States Geological Survey: Staff Publications

Chronic exposure of coral reefs to elevated nutrient conditions can modify the performance of the coral holobiont and shift the competitive interactions of reef organisms. Many studies have nowquantified the links between nutrients and coral performance, but fewhave translated these studies to directly address coastal water quality standards. To address this management need, we conducted a systematic review of peer-reviewed studies, public reports, and gray literature that examined the impacts of dissolved inorganic nitrogen (DIN: nitrate, nitrite, and ammonium) and dissolved inorganic phosphorus (DIP: phosphate) on scleractinian corals. The systematic review resulted in 47 studies with comparable data on coral …

Go to article

Mgrre_Thinsections_05_A_30, Mgrre Sep 2022

Mgrre_Thinsections_05_A_30, Mgrre

Thin Sections

No abstract provided.

Go to article

Coastalimagelib: An Open- Source Python Package For Creating Common Coastal Image Products, Maile P. Mccann, Dylan L. Anderson, Christopher R. Sherwood, Brittany Bruder, A. Spicer Bak, Katherine L. Brodie Sep 2022

Coastalimagelib: An Open- Source Python Package For Creating Common Coastal Image Products, Maile P. Mccann, Dylan L. Anderson, Christopher R. Sherwood, Brittany Bruder, A. Spicer Bak, Katherine L. Brodie

United States Geological Survey: Staff Publications

CoastalImageLib is a Python library that produces common coastal image products intended for quantitative analysis of coastal environments. This library contains functions to georectify and merge multiple oblique camera views, produce statistical image products for a given set of images, and create subsampled pixel instruments for use in bathymetric inversion, surface current estimation, run-up calculations, and other quantitative analyses. This package intends to be an open-source broadly generalizable front end to future coastal imaging applications, ultimately expanding user accessibility to optical remote sensing of coastal environments. This package was developed and tested on data collected from the Argus Tower, a …

Go to article

Mgrre_Thinsections_05_A_29, Mgrre Sep 2022

Mgrre_Thinsections_05_A_29, Mgrre

Thin Sections

No abstract provided.

Go to article

Transcriptome Signatures Of Wastewater Effluent Exposure In Larval Zebrafish Vary With Seasonal Mixture Composition In An Effluent-Dominated Stream, Emma B. Meade, Luke R. Iwanowicz, Nicklaus Neureuther, Gregory H. Lefevre, Dana W. Kolpin, Hui Zhi, Shannon M. Meppelink, Rachael F. Lane, Angela Schmoldt, Aurash Mohaimani, Olaf Mueller, Rebecca D. Klaper Sep 2022

Transcriptome Signatures Of Wastewater Effluent Exposure In Larval Zebrafish Vary With Seasonal Mixture Composition In An Effluent-Dominated Stream, Emma B. Meade, Luke R. Iwanowicz, Nicklaus Neureuther, Gregory H. Lefevre, Dana W. Kolpin, Hui Zhi, Shannon M. Meppelink, Rachael F. Lane, Angela Schmoldt, Aurash Mohaimani, Olaf Mueller, Rebecca D. Klaper

United States Geological Survey: Staff Publications

Wastewater treatment plant (WWTP) effluent-dominated streams provide critical habitat for aquatic and terrestrial organisms but also continually expose them to complex mixtures of pharmaceuticals that can potentially impair growth, behavior, and reproduction. Currently, few biomarkers are available that relate to pharmaceutical-specific mechanisms of action. In the experiment reported in this paper, zebrafish (Danio rerio) embryos at two developmental stages were exposed to water samples from three sampling sites (0.1 km upstream of the outfall, at the effluent outfall, and 0.1 km below the outfall) during base-flow conditions from two months (January and May) of a temperate-region effluent-dominated stream …

Go to article

Speleothems In Sandstone Crevice And Boulder Caves Of The Elbe River Canyon, Czech Republic, Jiří Adamovič, Jaroslav Kukla, Michal Filippi, Roman Skála, Noemi Mészárosová Sep 2022

Speleothems In Sandstone Crevice And Boulder Caves Of The Elbe River Canyon, Czech Republic, Jiří Adamovič, Jaroslav Kukla, Michal Filippi, Roman Skála, Noemi Mészárosová

International Journal of Speleology

A variety of speleothems are present in crevice and boulder caves developed in Cretaceous sandstones of the Elbe River Canyon in northern Czech Republic. A set of complementary instrumental mineralogical methods was applied to characterize the speleothems and cave dripwaters, including X-ray powder diffraction, scanning electron microscopy and microanalysis, Raman spectroscopy and optical emission spectrometry. Four morphological types were distinguished and characterized in terms of their mineral and chemical composition: 1, rusty brown mud-dominated coatings with micro-gours, composed of a mixture of clay minerals; 2, white “chalky” coatings (moonmilk) composed of calcite with minor gypsum; 3, cauliflower-shaped coralloids composed of …

Go to article

Sinistral Shear During Middle Jurassic Emplacement Of The Matancilla Plutonic Complex In Northern Chile (25.4◦ S) As Evidence Of Oblique Plate Convergence During The Early Andean Orogeny, S. P. Mavor, J. S. Singleton, G. Heuser, R. Gomila, N. M. Seymour, S. Williams, G. Arancibia Sep 2022

Sinistral Shear During Middle Jurassic Emplacement Of The Matancilla Plutonic Complex In Northern Chile (25.4◦ S) As Evidence Of Oblique Plate Convergence During The Early Andean Orogeny, S. P. Mavor, J. S. Singleton, G. Heuser, R. Gomila, N. M. Seymour, S. Williams, G. Arancibia

United States Geological Survey: Staff Publications

Arc magmatism in a continental subduction zone facilitates rheological weakening of the rigid upper plate, and can accommodate the partitioned trench-parallel component of oblique subduction into an intra-arc shear zone. We document a shear zone at latitude 25.4◦ S near Taltal, Chile that was associated with intrusion of the Matancilla Plutonic Complex at ~169 Ma to evaluate intra-arc deformation and possible tectonic plate configurations during this time period. Polyphase folding of Paleozoic metasedimentary rocks is overprinted by mylonitic fabrics that are most extensive in a zone up to 1.4 km wide in the thermal aureole of the granodioritic Matancilla …

Go to article

Mgrre_Thinsections_05_A_28, Mgrre Sep 2022

Mgrre_Thinsections_05_A_28, Mgrre

Thin Sections

No abstract provided.

Go to article

Sinistral Shear During Middle Jurassic Emplacement Of The Matancilla Plutonic Complex In Northern Chile (25.4◦ S) As Evidence Of Oblique Plate Convergence During The Early Andean Orogeny, S.P. Mavor, J.S. Singleton, G. Heuser, R Gomila, N.M. Seymour, S. Williams, G. Arancibia Sep 2022

Sinistral Shear During Middle Jurassic Emplacement Of The Matancilla Plutonic Complex In Northern Chile (25.4◦ S) As Evidence Of Oblique Plate Convergence During The Early Andean Orogeny, S.P. Mavor, J.S. Singleton, G. Heuser, R Gomila, N.M. Seymour, S. Williams, G. Arancibia

United States Geological Survey: Staff Publications

component of oblique subduction into an intra-arc shear zone. We document a shear zone at latitude 25.4◦ S near Taltal, Chile that was associated with intrusion of the Matancilla Plutonic Complex at ~169 Ma to evaluate intra-arc deformation and possible tectonic plate configurations during this time period. Polyphase folding of Paleozoic metasedimentary rocks is overprinted by mylonitic fabrics that are most extensive in a zone up to 1.4 km wide in the thermal aureole of the granodioritic Matancilla pluton, where contact metamorphic andalusite porphyroblasts are synkinematic with fabric development. Mylonite in metasedimentary rocks is overprinted by a ~130 Ma …

Go to article

Mgrre_Thinsections_05_A_27, Mgrre Sep 2022

Mgrre_Thinsections_05_A_27, Mgrre

Thin Sections

No abstract provided.

Go to article

Mgrre_Thinsections_05_A_26, Mgrre Sep 2022

Mgrre_Thinsections_05_A_26, Mgrre

Thin Sections

No abstract provided.

Go to article

Mgrre_Thinsections_05_A_25, Mgrre Sep 2022

Mgrre_Thinsections_05_A_25, Mgrre

Thin Sections

No abstract provided.

Go to article

Discovering Hidden Geothermal Signatures Using Non-Negative Matrix Factorization With Customized K-Means Clustering, V.V. Vesselinov, B. Ahmmed, M.K. Mudunuru, J.D. Pepin, E.R. Burns, D.L. Siler, S. Karra, R.S. Middleton Sep 2022

Discovering Hidden Geothermal Signatures Using Non-Negative Matrix Factorization With Customized K-Means Clustering, V.V. Vesselinov, B. Ahmmed, M.K. Mudunuru, J.D. Pepin, E.R. Burns, D.L. Siler, S. Karra, R.S. Middleton

United States Geological Survey: Staff Publications

Discovery of hidden geothermal resources is challenging. It requires the mining of large datasets with diverse data attributes representing subsurface hydrogeological and geothermal conditions. The commonly used play fairway analysis approach typically incorporates subject-matter expertise to analyze regional data to estimate geothermal characteristics and favorability. We demonstrate an alternative approach based on machine learning (ML) to process a geothermal dataset from southwest New Mexico (SWNM). The study region includes low- and medium-temperature hydrothermal systems. Several of these systems are not well characterized because of insufficient existing data and limited past explorative work. This study discovers hidden patterns and relations in …

Go to article

Mgrre_Thinsections_05_A_24, Mgrre Sep 2022

Mgrre_Thinsections_05_A_24, Mgrre

Thin Sections

No abstract provided.

Go to article

Mgrre_Thinsections_05_A_23, Mgrre Sep 2022

Mgrre_Thinsections_05_A_23, Mgrre

Thin Sections

No abstract provided.

Go to article

Mgrre_Thinsections_05_A_22, Mgrre Sep 2022

Mgrre_Thinsections_05_A_22, Mgrre

Thin Sections

No abstract provided.

Go to article

First Prev Next Last