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Temporal and spatial sources of silica for chert remain poorly constrained. Modern sources to the worlds oceans include silica in rivers > aeolian (dust) deposition > sea floor vents and submarine weathering. However, changes in aridity and dust flux during the Phanerozoic may explain variations in the ocean silica cycle and times and places of chert formation. The chemistry of fine quartz dust (FQD) provides a chemical mechanism for the transformation of FQD to polymorphs of silica in chert; FQD is readily dissolved, then reprecipitated as Opal-A by either biotic or abiotic processes. An unequivocal relation between increases in dust flux and biogenic opal-A in the western Pacific Ocean during the past 200 kyr...
This dataset contains the Digital Elevation Model (DEM) for Africa from the Hydrologic Derivatives for Modeling and Analysis (HDMA) database. The DEM data were developed and distributed by processing units. There are 19 processing units for Africa. The distribution files have the number of the processing unit appended to the end of the zip file name (e.g. af_dem_3_2.zip contains the DEM data for unit 3-2). The HDMA database provides comprehensive and consistent global coverage of raster and vector topographically derived layers, including raster layers of digital elevation model (DEM) data, flow direction, flow accumulation, slope, and compound topographic index (CTI); and vector layers of streams and catchment...
The data document the results of several microbe bioassays performed by the USGS on Phragmites australis plants, including those performed on mature leaves, seedlings, and dead leaf tissues exploration of the literature to find accounts of microbes associated with Phragmites worldwide. For the bioassays, we prepared 162 pure cultures isolated from Phragmites plants in North America along the east coast, Florida, the Gulf of Mexico, and the Great Lakes area, 125 of which were from a previous study, and 38 represent new collections. The DNA sequences used to identify the 37 new collections are included. Microbes were isolated from plants collected from 2015-2018. We performed assays using both North American plant...
Surficial geology (geo7_2ag).
Categories: Data,
pre-SM502.8;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Aaiun-Tarfaya Basin, Province 2066,
Abu Gharadiq Basin, Province 2038,
Africa,
Age,
Amhara Plateau, Province 7161,
This coverage includes arcs, polygons and polygon labels that describe U.S. Geological Survey defined geologic provinces of the Africa. Each province has a set of geologic characteristics distinguishing it from surrounding provinces. These characteristics may include the dominant lithologies, the age of the strata, and the structural style. Some provinces include multiple genetically-related basins. Offshore province boundaries are generally defined by the 2000 meter bathymetric contour, but where appropriate are defined by the 4000 meter bathymetric contour. In some cases province boundaries are delineated by political boundaries, as in the case of The United States and Canada, because United States petroleum resources...
At recent technical conferences, many coal geoscientists in academia and government institutions as well as in industry organizations have expressed concern about the dwindling number of students and young staff members interested in careers in coal geoscience. To better understand what is driving these trends and to identify potential ways that the community can increase interest and participation in coal geoscience, two different surveys were sent to 94 coal geoscientists who were current or past members of The Society of Organic Petrology (TSOP) in February 2020. As the trends and perceptions in industry and government organizations may be different than in universities, one distinct survey was sent to members...
Namib Desert. Aerial view of longitudinal dune. Africa. No date.
Categories: Image;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Africa,
Photographers,
aerial,
color transparency (slides)
Inland fishes provide important ecosystem services to communities worldwide and are especially vulnerable to the impacts of climate change. Fish respond to climate change in diverse and nuanced ways which creates challenges for practitioners of fish conservation, climate change adaptation, and management. Although climate change is known to affect fish globally, a comprehensive online, public database of how climate change has impacted inland fishes worldwide and adaptation or management practices that may address these impacts does not exist. We conducted an extensive, systematic primary literature review to identify peer-reviewed journal publications describing projected and documented examples of climate change...
This article compares US and Chinese incentives in winning oil contracts in African countries. Exploration and development of African oil resources has soared, and many nations are competing for these new oil contracts. China has won a significant portion of these oil contracts due to their unique incentive offerings. This report will address a brief history and the development of Sino–African policies and interests, modern US–African energy policy and interests, petroleum opportunities in Africa, China’s growing oil demand, and information on both American and Chinese incentives strategies. This information will be used to compare US and Chinese incentive strategies on winning African oil contracts. Implications...
This dataset contains the African continent from the Hydrological Derivatives for Modeling and Analysis (HDMA) database. The HDMA database provides comprehensive and consistent global coverage of raster and vector topographically derived layers, including raster layers of digital elevation model (DEM) data, flow direction, flow accumulation, slope, and compound topographic index (CTI); and vector layers of streams and catchment boundaries. The coverage of the data is global (-180º, 180º, -90º, 90º) with the underlying DEM being a hybrid of three datasets: HydroSHEDS (Hydrological data and maps based on SHuttle Elevation Derivatives at multiple Scales), Global Multi-resolution Terrain Elevation Data 2010 (GMTED2010)...
This data set contains the Compound Topographic Index (CTI) for Africa from the Hydrologic Derivatives for Modeling and Analysis (HDMA) database. The CTI data were developed and distributed by processing units. There are 19 processing units for Africa. The distribution files have the number of the processing unit appended to the end of the zip file name (e.g. af_cti_3_2.zip contains the CTI data for unit 3-2). The HDMA database provides comprehensive and consistent global coverage of raster and vector topographically derived layers, including raster layers of digital elevation model (DEM) data, flow direction, flow accumulation, slope, and compound topographic index (CTI); and vector layers of streams and catchment...
This dataset contains the slope for Africa from the Hydrologic Derivatives for Modeling and Analysis (HDMA) database. The slope data were developed and distributed by processing units. There are 19 processing units for Africa. The distribution files have the number of the processing unit appended to the end of the zip file name (e.g. af_slope_3_2.zip contains the slope data for unit 3-2).The HDMA database provides comprehensive and consistent global coverage of raster and vector topographically derived layers, including raster layers of digital elevation model (DEM) data, flow direction, flow accumulation, slope, and compound topographic index (CTI); and vector layers of streams and catchment boundaries. The coverage...
This is the first of two datasets containing derived data necessary to reproduce the results of the associated journal article: "On the Sensitivity of Annual Streamflow to Air Temperature." This first dataset contains basic basin characteristics of 2,673 gaged basins worldwide, along with associated monthly time series of basin-mean precipitation, air temperature, and net radiation. The streamflow data themselves are available directly from the Global Runoff Data Centre. From the inventory of discharge data holdings of the Global Runoff Data Centre, 2,673 stream gages were selected for which (1) at least 25 complete calendar years of monthly data overlapped in time with available climate data; (2) 500-m-resolution...
This dataset contains the streams derived from the Digital Elevation Model (DEM) for the African continent from the Hydrological Derivatives for Modeling and Analysis (HDMA) database. The HDMA database provides comprehensive and consistent global coverage of raster and vector topographically derived layers, including raster layers of digital elevation model (DEM) data, flow direction, flow accumulation, slope, and compound topographic index (CTI); and vector layers of streams and catchment boundaries. The coverage of the data is global (-180º, 180º, -90º, 90º) with the underlying DEM being a hybrid of three datasets: HydroSHEDS (Hydrological data and maps based on SHuttle Elevation Derivatives at multiple Scales),...
Africa. Slumps on barchan dune, 10 kilometers north of Walvis Bay, Namibia (South West Africa). 1977.
The North American Bird Banding Program is directed in the United States by the U.S. Geological Survey (USGS) Bird Banding Laboratory (BBL), Eastern Ecological Science Center at the Patuxent Research Refuge (EESC) and in Canada by the Bird Banding Office (BBO), Environment and Climate Change Canada (ECCC). The respective banding offices have similar functions and policies and use the same bands, reporting forms and data formats. Data contributors are US and Canadian bird banding permit holders: federal, state, tribal, local government, non-government agencies, business, university and avocational biologists. Bird banders capture wild birds and mark them with a metal leg band with a unique 9-digit number. Extra markers...
This dataset contains the Flow Direction (FD) for Africa from the Hydrologic Derivatives for Modeling and Analysis (HDMA) database. The FD data were developed and distributed by processing units. There are 19 processing units for Africa. The distribution files have the number of the processing unit appended to the end of the zip file name (e.g. af_fd_3_2.zip contains the FD data for unit 3-2).The HDMA database provides comprehensive and consistent global coverage of raster and vector topographically derived layers, including raster layers of digital elevation model (DEM) data, flow direction, flow accumulation, slope, and compound topographic index (CTI); and vector layers of streams and catchment boundaries. The...
Africa terrestrial ecosystems were modeled using a biophysical stratification approach based on mapping the major structural components of ecosystems. New 90 meter base resolution continental datasets were developed for several key physical environment datalayers including coastlines, land surface forms, surficial lithology, and bioclimates. These unique physical components, considered as the fundamental building blocks of ecosystems, were reviewed by regional vegetation and landscape ecology experts and used in a classification and regression tree (CART) inductive model to map intermediate scale Africa terrestrial ecosystems. In the final dataset a total of 126 terrestrial ecosystem types were mapped, each with...
This article compares US and Chinese incentives in winning oil contracts in African countries. Exploration and development of African oil resources has soared, and many nations are competing for these new oil contracts. China has won a significant portion of these oil contracts due to their unique incentive offerings. This report will address a brief history and the development of Sino–African policies and interests, modern US–African energy policy and interests, petroleum opportunities in Africa, China’s growing oil demand, and information on both American and Chinese incentives strategies. This information will be used to compare US and Chinese incentive strategies on winning African oil contracts. Implications...
The North American Bird Banding Program is administered through the U.S. Geological Survey (USGS) Bird Banding Laboratory (BBL), Eastern Ecological Science Center at the Patuxent Research Refuge (EESC) and the Bird Banding Office (BBO), Environment and Climate Change Canada (ECCC). The respective banding offices have similar functions and policies and use the same bands, reporting forms and data formats. This long-term dataset (1960-2023) consists of over 83 million bird banding, encounter and recapture records of over 1,000 species covered under the Migratory Bird Treaty Act (MBTA). Data is contributed by US and Canadian bird banding permit holders: federal, state, tribal, local government, non-government agencies,...
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