Mobilization of Lithium in Sedimentary Hydrothermal Systems

During the Deep Sea Drilling Project and its various successors studies of interstitial waters and sediments we have paid attention to the effects of hydrothermal alteration of sediments and igneous intrusions (sills), on the fluid and solid phases. Studies of both the geochemistry of lithium isotopes and strontium isotopes have revealed reactions taking place in these sediments. We use three different settings to describe observations on the lithium geochemical aspects of these hydrothermal reactions. Guaymas Basin Site 477 in the Gulf of California (Leg 64 DSDP) and also Site 482 in the mouth of the Gulf of California (Leg 65 DSDP) are discussed. In addition observations in Site 1038 in the Escanaba Trough further served this purpose. Future work on lithium geochemistry, both in hydrothermal systems and in sediments characterized by the occurrence of gas hydrates will serve to further delineate various aspects of lithium geochemistry.