HR: 17:44h
AN: V14A-09    [Abstracts]
TI: Ultra-high pressure and associated minerals separated from eclogite and garnet peridotite sampled in the CCSD Main Hole
AU: * Yang, J
EM: yangjsui@ccsd.org.cn
AF: Key Laboratory for Continental Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, 26 Baiwanzhuang Road, Beijing, 100037 China
AU: Zhang, Z
EM: yangjsui@ccsd.org.cn
AF: Key Laboratory for Continental Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, 26 Baiwanzhuang Road, Beijing, 100037 China
AU: Bai, W
EM: yangjsui@ccsd.org.cn
AF: Key Laboratory for Continental Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, 26 Baiwanzhuang Road, Beijing, 100037 China
AU: Fang, Q
EM: yangjsui@ccsd.org.cn
AF: Key Laboratory for Continental Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, 26 Baiwanzhuang Road, Beijing, 100037 China
AU: Ren, Y
EM: yfren@ccsd.org.cn
AF: Key Laboratory for Continental Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, 26 Baiwanzhuang Road, Beijing, 100037 China
AU: Xu, Z
EM: xzq@ccsd.org.cn
AF: Key Laboratory for Continental Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, 26 Baiwanzhuang Road, Beijing, 100037 China
AB: The Chinese Continental Scientific Drilling project (CCSD) is currently drilling a projected 5000-m-deep hole on the Sulu UHP metamorphic slab, which has now reached a depth of about 4400 m. Cuttings of eclogite and garnet peridotite from the CCSD main hole were collected for mineral studies. Minerals were separated by a variety of standard techniques and handpicked under a binocular microscope. Mineral identification was by a combination of microprobe, Laser Raman, and X-ray techniques. Thus far, over 50 individual minerals have been identified, including silicates, oxides, sulfides, carbonates, native elements, and metallic alloys. Numerous ultra-high pressure (UHP) minerals have been identified, such as diamond in eclogite, coesite in eclogite, moissanite, and w"1stite. Other phases include native Fe, Cr, Ni, Au, Cu, and Al, taenite, kamacite, Ni-Fe-Cr alloy, Ni-Fe alloy, Fe-Cr alloy, Si-Fe alloy (Fe3Si7), Co-Ni alloy, chalcopyrite, sphalerite, galena, limonite, titanomagnetite and kyanite. Common silicate minerals, such as olivine, pyroxene, garnet, rutile, phlogopite, and some alteration minerals, are also present. Most of the identified minerals are attached to, or included in, other minerals suggesting that they are natural phases, not contaminants. Some of the minerals, e.g., badeleyite, native Fe, taenite, Fe-Ni alloy, and magnetite are spheroidal, suggesting that they formed as liquid droplets from high-temperature melts. These minerals may have formed from mixtures of mantle and core materials. The minerals separated from the eclogites and peridotites of the CCSD-MH are comparable to those collected from the Luobusa ophiolite, Tibet, as well as those from Alpine-type ophiolites in the South Urals. However, the eclogites and peridotites of the CCSD-MH lack PGE minerals, indicating that the mantle rocks in the various localities had different origins.
DE: 0810 Post-secondary education
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2004 AGU Fall Meeting