Lawsonite metasomatism and trace element recycling in subduction zones
نویسندگان
چکیده
منابع مشابه
Subduction Zones
[1] Subduction zones are where sediments, oceanic crust, and mantle lithosphere return to and reequilibrate with Earth’s mantle. Subduction zones are interior expressions of Earth’s 55,000 km of convergent plate margins and are the geodynamic system that builds island arcs. Excess density of the mantle lithosphere in subduction zones provides most of the power needed to move the plates while in...
متن کاملTrace element transport rates in subduction zones: evidence from Th, Sr and Pb isotope data for Tonga-Kermadec arc lavas
Trace element and Th, Sr and Pb isotope data for young lavas from the Tonga-Kermadec arc in the southwest Pacific suggest that geochemical variations in the lavas along the arc are linked to differences in the material being subducted beneath the arc. Lavas from the southern (Kermadec) segment of the arc have relatively radiogenic Pb isotope compositions, which reflects a contribution from subd...
متن کاملConstraints from Thorium/Lanthanum on Sediment Recycling at Subduction Zones and the Evolution of the Continents
Arc magmas and the continental crust share many chemical features, but a major question remains as to whether these features are created by subduction or are recycled from subducting sediment. This question is explored here using Th/La, which is low in oceanic basalts (<0 2), elevated in the continents (>0 25) and varies in arc basalts and marine sediments (0 09–0 34). Volcanic arcs form linear...
متن کاملTrace Element Evidence for Hydrous Metasomatism at the Base of the North American Lithosphere and Possible Association with Laramide Low-Angle Subduction
Trace element signatures of mantle xenoliths along an east-west transect extending from the Sierra Nevada to the Colorado Plateau were investigated in this study. Those beneath the Sierra Nevada are highly enriched in fluid-mobile elements (Cs, Pb, U, and Sr) and, in particular, are characterized by low U/Pb and high Sr/Nd. These signatures imply that aqueous fluids derived by dehydration of se...
متن کاملSimple Kinematics of Subduction Zones
Two main types of subduction zones can be distinguished: (1) those where the subduction hinge migrates away from the upper plate; and (2) those in which the subduction hinge migrates toward the upper plate. Apart from a few exceptions, this distinction seems to apply particularly for W-directed subduction zones and Eor NE-directed subduction zones, respectively. Moreover, the rate of subduction...
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ژورنال
عنوان ژورنال: Journal of Metamorphic Geology
سال: 2014
ISSN: 0263-4929
DOI: 10.1111/jmg.12074