نتایج جستجو برای: rocks

تعداد نتایج: 22088  

2015
Alan D. Chapman Mihai N. Ducea Nadine McQuarrie Matthew Coble Lucian Petrescu Derek Hoffman

Newly discovered xenoliths within Pliocene and Quaternary intermediate volcanic rocks from southern Peru permit examination of lithospheric processes by which thick crust (60–70 km) and high average elevations (3–4 km) resulted within the Altiplano, the second most extensive orogenic plateau on Earth. The most common petrographic groups of xenoliths studied here are igneous or meta-igneous rock...

2006
Ramananda Chakrabarti Asish R. Basu

The Lonar impact crater in the Deccan Traps of the Indian peninsula provides unique opportunities to study physical and chemical processes of impact cratering on basaltic targets, because terrestrial impact craters on basalts are extremely rare. Such studies are needed for determining provenance and other parameters of the excavated rocks and the cratering phenomenon that may have implications ...

Journal: :Environmental entomology 2011
Joseph McCaffrey Candace Galen

Formica neorufibarbis Emery is a dominant alpine ant in North America. Above timberline, colonies nest under rocks, placing brood against the rock surface to warm during the day. We tested the hypothesis that nest rock preference represents a mechanism of behavioral thermoregulation and used a demographic model to explore its impact on the species' altitudinal range. Under sunny conditions roc...

2002
Jim L. Oliver C. Jay Hodgson

rocks of the Stuhuni and King Salmon Groups; a pre-.Middlm: Triassic unconformity is found througbmt the North American Cordillera (Read and Okulitch, 1977, Siberling, 1973:. In the Stikine Terrane, late Triassic volcanic rocks ar: dominantly fragmental andcommonly alkalic. Based on bul:: rock chemistry, both extensional, ba:k-arc, and Fore-ar: tectonic settings have been suggested tor these r...

Journal: :American journal of physiology. Cell physiology 2006
Kensuke Noma Naotsugu Oyama James K Liao

Rho-associated kinases (ROCKs), the immediate downstream targets of RhoA, are ubiquitously expressed serine-threonine protein kinases that are involved in diverse cellular functions, including smooth muscle contraction, actin cytoskeleton organization, cell adhesion and motility, and gene expression. Recent studies have shown that ROCKs may play a pivotal role in cardiovascular diseases such as...

2008
D. Stöffler R. A. F. Grieve

This work presents the provisional results of the IUGS Subcommission on the Systematics of Metamorphic Rocks in respect to impactites. It is proposed to distinguish between impactites resulting from a single impact (e.g., at terrestrial impact craters) and those resulting from multiple impacts (e.g., lunar rocks or meteorites). The former are subdivided into two major groups: Proximal and dista...

2005
E. Iglesias A. Razo

Petrophysical properties of geothermal reservoir rocks are valuable information for many activities, including reservoir characterization, modelling, field test analysis and planning of exploitation techniques. Petrophysical data of rocks from geothermal reservoirs located in volcanic areas is in general very scarce. In particular, no petrophysical data of rocks from the Los Azufres geothermal ...

2010
I. M. H. R. Antunes A. M. R. Neiva M. M. V. G. Silva

Five granitic rocks, concentrically disposed from core to rim, were distinguished in the Castelo Branco pluton. U-Pb-Th electron microprobe monazite ages from granitic rocks are similar and ranging between 297-303 Ma. The granitic rocks from Castelo Branco pluton are 310 ± 1 Ma old, obtained by U-Pb (ID-TIMS) in separated zircon and monazite crystals, indicating a similar emplacement age for al...

Journal: :Science 2014
R E Arvidson S W Squyres J F Bell J G Catalano B C Clark L S Crumpler P A de Souza A G Fairén W H Farrand V K Fox R Gellert A Ghosh M P Golombek J P Grotzinger E A Guinness K E Herkenhoff B L Jolliff A H Knoll R Li S M McLennan D W Ming D W Mittlefehldt J M Moore R V Morris S L Murchie T J Parker G Paulsen J W Rice S W Ruff M D Smith M J Wolff

Opportunity has investigated in detail rocks on the rim of the Noachian age Endeavour crater, where orbital spectral reflectance signatures indicate the presence of Fe(+3)-rich smectites. The signatures are associated with fine-grained, layered rocks containing spherules of diagenetic or impact origin. The layered rocks are overlain by breccias, and both units are cut by calcium sulfate veins p...

2017
Richard Kettler E. PAPASTAVROS

Sediments and rocks recovered in CRP-2/2A coring operations contain relatively little organic matter (average TOC=0.28%) and very small amounts of solvent-soluble organic matter. Because Early Oligocene sediment included significant amounts of coal detritus, TOC values are higher in Early Oligocene rocks than in younger rocks. TOC values are highest in the fine-grained rocks deposited as part o...

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