نتایج جستجو برای: serpentinization

تعداد نتایج: 347  

2017
Hector M Lamadrid J Donald Rimstidt Esther M Schwarzenbach Frieder Klein Sarah Ulrich Andrei Dolocan Robert J Bodnar

The hydrothermal alteration of mantle rocks (referred to as serpentinization) occurs in submarine environments extending from mid-ocean ridges to subduction zones. Serpentinization affects the physical and chemical properties of oceanic lithosphere, represents one of the major mechanisms driving mass exchange between the mantle and the Earth's surface, and is central to current origin of life h...

احمدی‌پور , حمید, محمدی, نادیه ,

Three types of serpentine polymorphs (lizardite, chrysotile and antigorite) are found in serpentinites from the Baft ophiolite mélange which are different in the textural features and chemical compositions. Lizardite is seen as layered structures that set in the matrix of peridotites, while antigorite is formed in veins or sheared zones as blade crystals and chrysotile develops as shiny and gol...

2012
Karthik Iyer

[1] The subduction of partially serpentinized oceanic mantle may potentially be the key geologic process leading to the regassing of Earth’s mantle and also has important consequences for subduction zone processes such as element cycling, slab deformation, and intermediate-depth seismicity. However, little is known about the quantity of water that is retained in the slab during mantle serpentin...

2006
Zheng-Xue Anser Li Cin-Ty Aeolus Lee

The petrology and geochemistry of serpentinized harzburgites within the Feather River Ophiolite in northern California were investigated to constrain the origin of serpentinization. Trace-element systematics indicate that serpentinization was associated almost solely with relatively low temperature hydrothermal addition of seawater and not with the addition of metamorphic fluids associated with...

2014
Marco Maffione Antony Morris Douwe J. J. van Hinsbergen

Serpentinization of ultramafic rocks during hydrothermal alteration at mid-ocean ridges profoundly changes the physical, chemical, rheological, and magnetic properties of the oceanic lithosphere. There is renewed interest in this process following the discovery of widespread exposures of serpentinized mantle on the seafloor in slow spreading oceans. Unroofing of mantle rocks in these settings i...

2007
Arnaud Agranier Cin-Ty A. Lee Zheng-Xue A. Li William P. Leeman

Serpentinized oceanic lithosphere may be an important source for boron and other fluid-mobile elements that are anomalously enriched in arc volcanic rocks. However, the integrated water/rock ratios associated with different styles of serpentinization may be variable. For example, large water/rock ratios are involved in the serpentinization of abyssal peridotites exhumed to the seafloor, whereas...

Journal: :journal of tethys 0

the serpentinization of the harzburgitic mantle section of the bou azzer neoproterozoic ophiolite is studied by field mapping, structural observations, optical micrography, sem and x-ray diffractometry, and relationships with co, ni, cr and sulphides minerals are discussed. serpentinization occurred in two major steps with, i) intra-oceanic pseudomorphic serpentinization materialized by the iso...

2013
Matthew O. Schrenk William J. Brazelton Susan Q. Lang

The aqueous alteration of ultramafic rocks through serpentinization liberates mantle carbon and reducing power. Serpentinization occurs in numerous settings on present day Earth, including subduction zones, mid-ocean ridges, and ophiolites and has extended far into Earth’s history, potentially contributing to the origins and early evolution of life. Serpentinization can provide the energy and r...

Journal: :Science 2003
Gretchen L Früh-Green Deborah S Kelley Stefano M Bernasconi Jeffrey A Karson Kristin A Ludwig David A Butterfield Chiara Boschi Giora Proskurowski

Strontium, carbon, and oxygen isotope data and radiocarbon ages document at least 30,000 years of hydrothermal activity driven by serpentinization reactions at Lost City. Serpentinization beneath this off-axis field is estimated to occur at a minimum rate of 1.2 x 10(-4) cubic kilometers per year. The access of seawater to relatively cool, fresh peridotite, coupled with faulting, volumetric exp...

2015
N.G. Holm C. Oze O. Mousis J.H. Waite A. Guilbert-Lepoutre

Serpentinization involves the hydrolysis and transformation of primary ferromagnesian minerals such as olivine ((Mg,Fe)2SiO4) and pyroxenes ((Mg,Fe)SiO3) to produce H2-rich fluids and a variety of secondary minerals over a wide range of environmental conditions. The continual and elevated production of H2 is capable of reducing carbon, thus initiating an inorganic pathway to produce organic com...

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