نتایج جستجو برای: basalt

تعداد نتایج: 3610  

2017
Ebbe N. Bak Michael G. Larsen Ralf Moeller Silas B. Nissen Lasse R. Jensen Per Nørnberg Svend J. K. Jensen Kai Finster

The habitability of Mars is determined by the physical and chemical environment. The effect of low water availability, temperature, low atmospheric pressure and strong UV radiation has been extensively studied in relation to the survival of microorganisms. In addition to these stress factors, it was recently found that silicates exposed to simulated saltation in a Mars-like atmosphere can lead ...

2008
R. V. Morris G. Klingelhöfer C. Schröder I. Fleischer D. W. Ming A. S. Yen R. Gellert R. E. Arvidson D. S. Rodionov L. S. Crumpler B. C. Clark B. A. Cohen T. J. McCoy D. W. Mittlefehldt M. E. Schmidt P. A. de Souza S. W. Squyres

[1] Spirit’s Mössbauer (MB) instrument determined the Fe mineralogy and oxidation state of 71 rocks and 43 soils during its exploration of the Gusev plains and the Columbia Hills (West Spur, Husband Hill, Haskin Ridge, northern Inner Basin, and Home Plate) on Mars. The plains are predominantly float rocks and soil derived from olivine basalts. Outcrops at West Spur and on Husband Hill have expe...

2008
R. V. Morris G. Klingelhöfer C. Schröder I. Fleischer D. W. Ming A. S. Yen R. Gellert R. E. Arvidson D. S. Rodionov L. S. Crumpler B. C. Clark B. A. Cohen T. J. McCoy D. W. Mittlefehldt M. E. Schmidt P. A. de Souza S. W. Squyres

[1] Spirit’s Mössbauer (MB) instrument determined the Fe mineralogy and oxidation state of 71 rocks and 43 soils during its exploration of the Gusev plains and the Columbia Hills (West Spur, Husband Hill, Haskin Ridge, northern Inner Basin, and Home Plate) on Mars. The plains are predominantly float rocks and soil derived from olivine basalts. Outcrops at West Spur and on Husband Hill have expe...

2009
Beth Orcutt Brad Bailey Hubert Staudigel Bradley M Tebo Katrina J Edwards

We present an interlaboratory comparison between full-length 16S rRNA gene sequence analysis and terminal restriction fragment length polymorphism (TRFLP) for microbial communities hosted on seafloor basaltic lavas, with the goal of evaluating how similarly these two different DNA-based methods used in two independent labs would estimate the microbial diversity of the same basalt samples. Two s...

2018
Nicolas Bost Francès Westall Fabrice Gaillard Claire Ramboz Frédéric Foucher Nicolas BOST Frances WESTALL Fabrice GAILLARD Claire RAMBOZ Frédéric FOUCHER

Analyses by the Mars Exploration Rover (MER), Spirit, of Martian basalts from Gusev crater show that they are chemically very different from terrestrial basalts, being characterized in particular by high Mgand Fe-contents. To provide suitable analog basalts for the International Space Analogue Rockstore (ISAR), a collection of analog rocks and minerals for preparing in situ space missions, espe...

2003
Susan J. Lutz Joseph N. Moore

The main reservoir in the Dixie Valley geothermal field of Nevada is hosted in fractured Jurassic rocks within the hanging wall of the Stillwater fault. Within the Jurassic sequence, at least four major stages of alteration related to the fault system can be identified. The paragenetic sequence from oldest to youngest consists of Stage I) biotite-potassium feldspar veins, and epidote-chlorite-c...

2010
Mark E. Nielsen Martin R. Fisk

[1] These first measurements of specific surface area (SSA) of bulk samples of subsurfacemarine basalts were undertaken to determine the potential area available for microbial colonization. SSA ranged from 0.3 to 52 m/g of basalt with the lowest value coming from pillow basalt and the highest value from breccia. The average for massive and pillow basalts combined was 2.3 m/g. The total specific...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1996
M I Weisler P V Kirch

Tracing interisland and interarchipelago movements of people and artifacts in prehistoric Polynesia has posed a challenge to archaeologists due to the lack of pottery and obsidian, two materials most readily used in studies of prehistoric trade or exchange. Here we report the application of nondestructive energy-dispersive x-ray fluorescence (EDXRF) analysis to the sourcing of Polynesian artifa...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2016
Yang Zhao Jia-Wei Tang Zhi Yang Yi-Bin Cao Ji-Long Ren Yuval Ben-Abu Kexin Li Xue-Qun Chen Ji-Zeng Du Eviatar Nevo

Epigenetic modifications play significant roles in adaptive evolution. The tumor suppressor p53, well known for controlling cell fate and maintaining genomic stability, is much less known as a master gene in environmental adaptation involving methylation modifications. The blind subterranean mole rat Spalax eherenbergi superspecies in Israel consists of four species that speciated peripatricall...

2017
Lin Sang Mingyuan Zhao Qiushi Liang Zhiyong Wei

In this work, an economical modifier silane agent—KH550—was used for surface treatment of basalt fiber. Then, a biodegradable poly(butylene succinate) (PBS)/modified basalt fiber (MBF) biocomposite was successfully developed. The effects of silane treatment and fiber mass content on crystalline structure, isothermal crystallization process and mechanical performance of composites were evaluated...

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