نتایج جستجو برای: mineral rocks

تعداد نتایج: 86424  

2014
Trevor P. Almeida Takeshi Kasama Adrian R. Muxworthy Wyn Williams Lesleis Nagy Thomas W. Hansen Paul D. Brown Rafal E. Dunin-Borkowski

Magnetite (Fe3O4) is an important magnetic mineral to Earth scientists, as it carries the dominant magnetic signature in rocks, and the understanding of its magnetic recording fidelity provides a critical tool in the field of palaeomagnetism. However, reliable interpretation of the recording fidelity of Fe3O4 particles is greatly diminished over time by progressive oxidation to less magnetic ir...

2004
Donald J. DePaolo

Available constraints on metamorphic reaction rates derived from the study of natural systems are similar to, or slightly lower than, the bulk strain rates measured in the same rocks. Here, we explore whether this apparent relationship is merely coincidence or due to a more fundamental mechanistic link between reaction and strain. Grain boundary migration accommodated dislocation creep (GBMDC) ...

2011
Amy Smith Radu Popa Martin Fisk Mark Nielsen Hans W. Jannasch Andrew T. Fisher Keir Becker Stefan M. Sievert Gilberto Flores

[1] The Integrated Ocean Drilling Program (IODP) Hole 1301A on the eastern flank of Juan de Fuca Ridge was used in the first long‐term deployment of microbial enrichment flow cells using osmotically driven pumps in a subseafloor borehole. Three novel osmotically driven colonization systems with unidirectional flow were deployed in the borehole and incubated for 4 years to determine the microbia...

2011
S. Daghino E. Martino S. Perotto

Geomycology investigates the impact of fungi on geological processes, including the alteration and weathering of rocks and minerals, mediated both by biomechanical and by biochemical activities. Several functional groups of fungi are involved in mineral bioweathering, including saprotrophic and mycorrhizal fungi. Serpentine sites provide interesting environmental cases for geomycology, because ...

2012
W. David Wendell Mendell

This chapter discusses the physical properties of the lunar surface, determined at depths varying from a few micrometers to a few tens of meters. The properties considered include geotechnical properties (those properties of a planetary surface needed to evaluate engineering problems, including the mechanical properties of soil and rock), electrical and electromagnetic properties, and the refle...

آهنکوب, مریم , داودیان دهکردی, علیرضا , شبانیان بروجنی, ناهید , مکی‌زاده, محمد علی,

The studied gabbroic rocks have exposures around Darreh-Bid salt dome. The rocks are located about 130 km south of Shahrekord (Chaharmahal and Bakhtiari Province).  The studied area is a part of Zagros structural zone. Mineral chemistry studies were done on clinopyroxenes in the gabbroic rocks of the Darreh- Bid salt dome. The clinopyroxenes are diopsid and augite and are plotted in low pressur...

, Fatahi, Ahangari, , Asadpou, ,

The volcanic rocks with the Plio-Quaternary age, are exposed in the northern part of the Sanandaj-Sirjan zone, in northwest Urmia. The main mineral phases are olivin + clinopyroxene ± plagioclase, that are present as both phenocrysts to microcrystalline with other minor minerals. The dominant textures of these rocks are porphyry, microlithic porphyry, hyalo-porphyry, glomeroporphyritic and vesi...

2002
A. I. Okay O. Monod P. Monié

Triassic eclogite and blueschist facies rocks occur as a thrust sheet, 25-km long and over 2-km thick, in an Eocene fold-andthrust belt in northwest Turkey along the İzmir–Ankara suture. The thrust sheet consists mainly of metabasites with minor marble, phyllite and metachert, and rare lenses of serpentinite. The common blueschist facies mineral assemblage in the metabasites is sodic amphibole ...

شبانیان بروجنی, ناهید, داودیان دهکردی, علیرضا , سهیلیان , فرنوش ,

Gabbroic pluton of Bagham is located in southeastern Ardestan and has intruded into Eocene volacanic rocks. The study area is a part of Central Iranian zone and Urumieh-Dokhtar magmatic belt. Clinopyroxene, plagioclase and amphibole are main minerals in the pluton. Mineral chemistry studies show that clinopyroxenes are augite and are plotted in almost medium pressure field. The clinopyroxene co...

2013
Joel A. Hurowitz Woodward W. Fischer

The nature of ancient hydrological systems onMars has been the subject of ongoing controversy, driven largely by a disconnect between observational evidence for flowing water on the Martian surface at multiple scales and the incompatibility of such observations with theoretical models that predict a cold early Martian environment in which liquid water is unstable. Here we present geochemical da...

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