Crust/Mantle Recycling at Convergence Zones

This book consists of a collection of papers presented at the NATO Advanced Research Workshop (ARW) on "Crust/mantle Recycl ing at Convergence Zones," held in Antalya, Turkey, between May 25 to 29, 1987. The workshop was attended by 36 earth scientists from ten countries and 28 papers were presented. Crust/mantle recycling is one of the most fundamental processes in the Earth. The study and understanding of this process requires the consideration of the Earth as a whole system including the atmosphere, the hydrosphere and the core, as well as the crust and the mantle; effective interdisciplinary collaboration is therefore essential to our progress. The Antalya ARW gave us the opportunity to assemble key specialists from relevant branches of the earth sciences and to address our state of knowledge. This ARW proved to be very useful in attaining an interdisciplinary, mutual understanding among specialists from diverse fields such as isotope and trace element geochemistry, mineral physics, theoretical geophysics, seismology, experimental petrology, and structural geology.

Contenu

1. Mantle cycling: Process and time scales.- 2. Isotopic characterization and identification of recycled components.- 3. Hydrothermal alteration of the oceanic crust.- 4. Use of multispace technique to determine the contribution of reinjected sediments in the mantle (e.g., Lesser Antilles).- 5. Geochemical evidence for crust-to-mantle recycling in subduction zones.- 6. Kerguelen Archipelago: Geochemical evidence for recycled material.- 7. Subduction of young lithosphere: Lithospheric doubling, a possible scenario.- 8. A review of the thermal-mechanical structures at convergent plate boundaries and their implications for crust/mantle recycling.- 9. Sediment recycling at convergent margins: constraints from the cosmogenic isotope 10Be.- 10. Geophysical constraints on recycling of oceanic lithosphere.- 11. Influence of H2O and CO2 on melt and fluid chemistry in subduction zones.- 12. Anhydrous HFSE depleted peridotite as a ubiquitous mantle component.- 13. Volatiles and stable isotopes in recycling.- 14. Magma generation in subduction zones.- 15. Recycled continental crustal components in Aleutian arc magmas: implications for crustal growth and mantle heterogeneity.- 16. Tomographic mapping of the upper mantle structure beneath the Alpine collision belt.- 17. From plate tectonics to global domain tectonics.- 18. Isotopic and chemical signatures of recycled oceanic and continental crust.- 19. Mantle convection with active chemical heterogeneities.- 20. Crustal recycling and subduction: systems perspective.- 21. One-and-a-half layer convection?.- 22. Mineral physics and mantle evolution.- 23. Crust-mantle recycling: inputs and outputs.- 24. The structure of mantle flow and the stirring and persistence of chemical heterogeneities.- 25. Intra-mantle fractionation vs. lithosphere recycling: evidence from the sub-continental mantle.- 26. Convection and gravity close to subduction in a two layer mantle: a 3-D modelisation.- 27. Dynamics of recycling.- 28. Some speculations on continental evolution.