TY - JOUR
AU - Niu, Yaoling
AB - SONG ET AL.: ULTRA-DEEP ORIGIN OF GARNET PERIDOTITE FROM THE NORTH QAIDAM 1331 American Mineralogist, Volume 89, pages 1330–1336, 2004 Ultra-deep origin of garnet peridotite from the North Qaidam ultrahigh-pressure belt, Northern Tibetan Plateau, NW China 1 1, 2 SHUGUANG SONG, LIFEI ZHANG, * AND YAOLING NIU MOE Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking University, Beijing 100871, China Department of Geosciences, University of Houston, Houston, Texas 77204, U.S.A. ABSTRACT Exsolution textures are observed in garnet and olivine crystals found in an orogenic garnet pe- ridotite massif in the North Qaidam ultrahigh-pressure metamorphic (UHP) belt, northern Tibetan Plateau, NW China. Exsolutions in garnet consist of densely packed rods of rutile, orthopyroxene, and clinopyroxene. Exsolutions in olivine includes needles of ilmenite and Al-chromite. The occurrence of pyroxene exsolution lamellae in garnet crystals suggests that the precursor phase originally must have possessed excess Si, i.e., they were majoritic garnets that are stable only at very high pressures. The exsolution of ilmenite and Al-chromite needles from olivine is also consistent with the peridotite once being equilibrated at depths in excess of 200 km. Geotheromobarometric calculations using matrix minerals of the peridotite yield re-equilibrium conditions 
TI - Ultra-deep origin of garnet peridotite from the North Qaidam ultrahigh-pressure belt, Northern Tibetan Plateau, NW China
JF - American Mineralogist
DO - 10.2138/am-2004-8-922
DA - 2004-08-01
UR - https://www.deepdyve.com/lp/de-gruyter/ultra-deep-origin-of-garnet-peridotite-from-the-north-qaidam-ultrahigh-5OIwKsphJT
SP - 1330
EP - 1336
VL - 89
IS - 8-9
DP - DeepDyve
ER -