Intra-slab COH fluid fluxes evidenced by fluid-mediated decarbonation of lawsonite eclogite-facies altered oceanic metabasalts
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چکیده
منابع مشابه
Eclogite-facies fluid infiltration: constraints from dO zoning in garnet
In situ analysis reveals that eclogite-facies garnets are zoned in dO with lower values in the core and rims that are *1.5 to 2.5 % higher. This pattern is present in 9 out of 12 garnets analyzed by SIMS from four orogenic eclogite terranes, and correlates with an increase in the mole fraction of pyrope and Mg/Fe ratio from core to rim, indicating prograde garnet growth. At the maximum temperat...
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Eclogites from the Tian Shan high-pressure/low-temperature (HP/LT) metamorphic belt show evidence for successively increasing metasomatic alteration with increasing retrograde, blueschist-facies overprint. To constrain the source(s) of the metasomatizing fluid and to evaluate elemental and isotopic changes during this overprint, two sequences of eclogiteblueschist transitions were investigated:...
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Subducted oceanic metabasalts are believed to be a primary source of volatiles for arc magmatism and fluid-induced seismicity. From phase equilibria computed for an average oceanic metabasalt we present a model for subduction zone devolatilization for pressures up to 6 GPa (V180 km). Along high temperature geotherms complete dehydration occurs under forearcs, whereas dehydration does not occur ...
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Lawsonite eclogites represent fossil records of processes occurring during subduction of cold and fast-subducting slabs, and provide the opportunity to investigate the thermal and metamorphic evolution of palaeosubduction zones. Occurrences of lawsonite eclogites are rare because lawsonite is often replaced during exhumation. We report here, for the first time, the occurrence of a lawsonite ecl...
متن کاملBuoyancy Fluxes in a Stratified Fluid
Direct numerical simulations of the time evolution of homogeneous stably stratified shear flows have been performed for mean flow Richardson numbers in the range from 0.075 to 1.00 and for Prandtl numbers ranging from 0.1 to 2. The local or instantaneous results indicate that when the turbulent Froude number FrT = 1 the peak value of mixing efficiency is Rf ≈ 0.25, a result independent of the P...
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ژورنال
عنوان ژورنال: Lithos
سال: 2018
ISSN: 0024-4937
DOI: 10.1016/j.lithos.2018.01.028