Subsurface structure of a submarine hydrothermal system in ocean crust formed at the East Pacific Rise, ODP/IODP Site 1256
نویسندگان
چکیده
[1] ODP/IODP Hole 1256D penetrates an in situ section of ocean crust formed at the East Pacific Rise, through lavas and sheeted dikes and ∼100 m into plutonic rocks. We use mineralogy, oxygen isotopes, and fluid inclusions to understand hydrothermal processes. The lavas are slightly altered at low temperatures (<150°C) to phyllosilicates and iron oxyhydroxides, with a stepwise increase in grade downward to greenschist minerals in the upper dikes. This resulted from generally upwelling hydrothermal fluids in the dikes mixing with cooler seawater solutions in the lavas, also producing minor metal sulfide mineralization
منابع مشابه
Leg 206 Preliminary Report (Text and T1-T11)
Drilling a complete section of oceanic crust has been an unfulfilled ambition since the inception of scientific ocean drilling. Recovery of in situ oceanic crust is imperative to understand igneous accretion and the complex interplay between magmatic, hydrothermal, and tectonic processes, as well as a means for calibrating remote geophysical observations, particularly seismic and magnetic data....
متن کاملIodp Expedition 309: Superfast Spreading Rate Crust 2 Site 1256 Summary
Expedition 309, “Superfast Spreading Rate Crust 2,” successfully deepened Hole 1256D (6.736°N, 91.934°W) by 503 m to a total depth of 1255.1 meters below seafloor (mbsf) or 1005.1 meters subbasement. The average rate of core recovery for the expedition was 36%. Much higher rates of recovery were experienced in the lowermost section of the hole (~70% average below 1200 mbsf). At the end of Exped...
متن کاملStable isotopic composition of upper oceanic crust formed at a fast spreading ridge, ODP Site 801
[1] ODP Legs 129 and 185 sampled the upper 474 m of 170 Ma ocean crust in the western Pacific in order to investigate alteration processes in fast spread crust and to determine inputs to subduction. Fourteen composite bulk samples of altered upper oceanic crust from Site 801 have dO = 8.7–25.7%, dD = 69.4% to 90.4%, and dC = 2.7% to 1.8%. The intensity of alteration and the amount of sediment w...
متن کاملArchaeal phylotypes in a metal-rich and low-activity deep subsurface sediment of the Peru Basin, ODP Leg
Site 1231 of the Ocean Drilling Project (ODP) was characterized by low concentrations of organic carbon, as well as low cell numbers and biological activity rates. A 16S rRNA survey was performed in order to analyse the microbial community composition of these central oceanic sediments. Archaeal 16S rRNA genes from subsurface sediments at Site 1231 (1.8, 9.0, and 43 mbsf) were affiliated with u...
متن کاملHydrothermal systems and mineralization of volcanic arcs: Comparison of West Pacific and Mediterranean arcs
Introduction Hydrothermal systems and their associated metal deposits have been studied at oceanic spreading centers since the late 1970s when they were first discovered. More recently, those studies have been extended to subduction zone hydrothermal systems including active volcanic arcs and back-arc environments. Oceanic spreading centers compose a global ridge system where new ocean crust is...
متن کامل