Titlebook: Crust/Mantle Recycling at Convergence Zones; Stanley R. Hart,Levent Gülen Book 1989 Kluwer Academic Publishers 1989 atmosphere.chemistry.g

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Ethnomethodology in/for Science Education,y of this heterogeneous character has been expanded over the intervening years with the application of new isotopic tracer systems (Nd, Hf, He, Xe) to volcanic rocks from most of the oceanic islands. Currently, this isotopic heterogeneity can be embraced as mixtures between four or five fairly disti

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Glosses and Glossing Practices,nt contribution to the flux of material between the continent and the depleted mantle (Albarede and Michard, 1986). The subducted oceanic crust is expected to comprise widely different end-members: continent-derived sediments of which the abyssal clays are an important fraction, metalliferous ridge-

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Conclusions and Some Implications,e most part is derived from the continental crust. It also reacts with sea water and hydrothermal fluids produced from sea water, changing its composition. To the degree this sediment is subducted along with the basaltic portion of the oceanic crust, continental crust is recycled into the mantle. Th

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Understanding Culture Brokerage,from which oceanic basalts may be produced by variable mixing relationships, assuming that oceanic basalt isotope systematics reflect mixing. The existence of two additional components, BSE and PREMA, is also compatible with the observed isotopic heterogeneities in the mantle. The combinations of en

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Conclusions and Some Implications,ratification, rheology, and buoyancy. It is proposed that young oceanic lithosphere (< 20 Ma) and oceanic ridges, when being subducted upon being overridden by cool and strong (continental) lithosphere resides subhorizontally in the shallow upper mantle underneath a cooler upper lithospheric plate.

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Conclusions and Some Implications, and in time they will be assimilated through heating. This represents the large scale crust/mantle recycling process. There are other processes that contribute to recycling at smaller scales. Island arc volcanism and back-arc spreading at convergent plate boundaries are some of the examples. Dynami

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