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At least 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Stable Isotope and Geochemical Evidence for Hydrological Isolation in an Arctic Coastal Plain Landscape, Barrow, Alaska, 2013

Data include results from water chemistry and water isotope analyses for samples collected in Barrow, Alaska during July and September 2013. Samples were from surface and soil pore waters from 15 locations: 3 locations from interlake polygonal terrain, 6 locations associated with interlake drainages, and 6 locations within or at the outlets of different aged drained thaw lake basins (DTLBs). Samples were taken in different drainage flow types at three different depths at each location in and around the Barrow Environmental Observatory. This dataset includes one .csv data file and one .pdf user guide.The Next-Generation Ecosystem Experiments: Arctic (NGEE Arctic), was a 15-year research effort (2012-2027) to reduce uncertainty in Earth System Models by developing a predictive understanding of carbon-rich Arctic ecosystems and feedbacks to climate. NGEE Arctic was supported by the Department of Energy's Office of Biological and Environmental Research.The NGEE Arctic project had two field research sites: 1) located within the Arctic polygonal tundra coastal region on the Barrow Environmental Observatory (BEO) and the North Slope near Utqiagvik (Barrow), Alaska and 2) multiple areas on the discontinuous permafrost region of the Seward Peninsula north of Nome, Alaska. Through observations, experiments, and synthesis with existing datasets, NGEE Arctic provided an enhanced knowledge base for multi-scale modeling and contributed to improved process representation at global pan-Arctic scales within the Department of Energy's Earth system Model (the Energy Exascale Earth System Model, or E3SM), and specifically within the E3SM Land Model component (ELM).

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1966

New techniques in geochemical analysis

Thin layer and gas chromatography, Mossbauer and atomic absorption spectrometry, fission track analysis, X-ray fluorescence spectroscopy, and other methods employed in geochemistry

X-RAY FLUORESCENCE SPECTROSCOPY↗
NASA NTRS1972

Apollo 14: Some geochemical aspects

Chemical analyses were obtained for five samples of Apollo 14 regolith fines, three 14230 core samples, soil clod 14049, breccias 14305 and 14319, 14310 basalt, and some separated phases. The chemical uniformity of these Apollo 14 samples indicates thorough mixing and/or uniform source rocks. Basalt 14310 can be matched well in composition by a four to one mixture of soil and plagioclase. The Eu(2+)/Eu(3+) ratios calculated for 14310 pigeonite and plagioclase are similar to those for Apollo 12 and 15 mare-type basalt phases; this indicates similar redox conditions. Apollo 14 samples are chemically similar to Apollo 12 and 15 KREEP as distinct from Apollo 11, 12, and 15 and Luna 16 mare-type basalts.

Philpotts, J. A.↗
NASA NTRS1972

Apollo 16 geochemical X-ray fluorescence experiment: Preliminary report

The lunar surface was mapped with respect to Mg, Al, and Si, as Al/Si and Mg/Si ratios along the projected ground tracks swept out by the orbiting Apollo 16 spacecraft. The results confirm the observations made during the Apollo 15 flight and provide data for a number of features not covered before. The data are consistent with the idea that the moon has a widespread differentiated crust (the highlands). The Al/Si and Mg/Si chemical ratios correspond to that for anorthositic gabbro through gabbroic anorthosites or feldspathic basalts. The X-ray results suggest the occurrence of this premare crust or material similar to it as the Descartes landing site.

Adler, I.↗
NASA NTRS1972

Apollo 16 geochemical X-ray fluorescene experiment: Preliminary report

The lunar surface was mapped with respect to Mg, Al and Si as Al/Si and Mg/Si ratios along the projected ground tracks swept out by the orbiting Apollo 16 spacecraft. The results confirm the observations made during the Apollo 15 flight and provide data for a number of features not covered before. The data are consistent with the idea that the moon has a widespread differentiated crust (the highlands). The Al/Si and Mg/Si chemical ratios correspond to those for anorthositic gabbro through gabbroic anorthosites or feldspathic basalts. The X-ray results suggest the occurrence of this premare crust, or material similar to it, at the Descartes landing site.

Adler, I.↗
NASA NTRS1971

Geochemical aspects of some Japanese lavas.

K, Rb, Sr, Ba and rare-earth concentrations in some Japanese lavas have been determined by mass-spectrometric stable-isotope dilution. The samples fall into three rare-earth groups corresponding to tholeiitic, high alumina and alkali basalts. Japanese tholeiites have trace element characteristics similar to those of oceanic ridge tholeiites except for distinctly higher relative concentrations of Ba. Japanese lavas may result from various degrees of partial fusion of amphibole eclogite.

Philpotts, J. A.↗
NASA NTRS1972

Compound classification by computer treatment of low resolution mass spectra - Application to geochemical and environmental problems.

A description is given of a development of computer analysis of low-resolution chromatographic-mass spectrometric data, which provides a preliminary classification of an unknown spectrum as a listing of candidate classes of compounds. This procedure, referred to as COMSOC (Classification of Mass Spectra on Computers), operates by converting an incoming unknown mass spectrum into a simplified key word which is then compared with each of the key words held in its reference file. The advantages of COMSOC in characterizing complex mixtures are emphasized.

Smith, D. H.↗