P.I.: Peucker-Ehrenbrink Proposal Number: 98-11209 Institution: WHOI
We will study the effects of hydrothermal alteration on the distribution of platinum-group elements (PGE) and U-Th-Pb in altered oceanic crust. Elements from both groups are considered key evidence for important differentiation processes on Earth. The time-integrated effects of hydrothermal alteration will be studied on rocks and minerals from DSDP/ODP hole 504B, because it provides the most complete cross-section through altered oceanic crust. Samples will be analyzed for Re-Ru-Pd-Os (Os isotopes)-Ir-Pt, U-Th-Pb (Pb isotopes), Sr- isotopes, and complementary trace elements mobile during hydrothermal alteration (e.g., Li, K, Rb, Cs, Ba, Tl, Sb). Combining isotope and trace element analyses on samples from a variety of alteration environments with analyses of minerals from both primary and secondary mineral assemblages will enable us to constrain the effects of hydrothermal alteration on the redistribution of PGE and U-Th-Pb in oceanic crust.
