Abstract
Millimeter-scale amphibole veins in the lower oceanic crust record fracture-controlled fluid flow at high-temperatures but the importance of this fluid flow for the thermal and chemical evolution of the lower oceanic crust is unclear. In the section of lower oceanic crust recovered at Hess Deep from ODP Hole 894G, which formed at the fast-spreading East Pacific Rise, these veins are randomly distributed with an average spacing of similar to 1 m. We unravel the history of fluid flow through one of these veins by combining in situ O-isotope analyses of wall-rock plagioclase with major element analyses, geothermometry and diffusion modeling. Thermometry indicates vein sealing by amphibole at similar to 720 degrees C over a narrow temperature interval (+/- 20 degrees C). In situ O-isotope analyses by ion microprobe, with a precision of
Original language | English |
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Pages (from-to) | 524-536 |
Number of pages | 13 |
Journal | Earth and Planetary Science Letters |
Volume | 260 |
Issue number | 3-4 |
DOIs | |
Publication status | Published - 30 Aug 2007 |
Keywords / Materials (for Non-textual outputs)
- oceanic crust
- hydrothermal circulation
- O-isotope
- diffusion
- Hess Deep
- EAST PACIFIC RISE
- HESS-DEEP
- HYDROTHERMAL CIRCULATION
- SAMAIL OPHIOLITE
- OMAN OPHIOLITE
- ION MICROPROBE
- DIFFUSION
- FRACTIONATION
- AMPHIBOLES
- MINERALS