Metamorphic rocks of the 1985 Tibet Geotraverse, Lhasa to Golmud

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Authors:Harris, N. B. W.; Holland, T. J. B.; Tindle, A. G.
Author Affiliations:Primary:
Open Univ., Dep. Earth Sci., Milton Keynes, United Kingdom
Open Univ., United Kingdom
Univ. Oxford, United Kingdom
Univ. Cambridge, United Kingdom
Volume Title:geological evolution of Tibet; report of the 1985 Royal Society - Academia Sinica geotraverse of the Qinghai-Xizang Plateau
Volume Authors:Chang Chengfa, leader; Shackleton, Robert M.; Dewey, John F.; Yin Jixiang
Source:The geological evolution of Tibet; report of the 1985 Royal Society - Academia Sinica geotraverse of the Qinghai-Xizang Plateau, leaded by Chang Chengfa, Robert M. Shackleton, John F. Dewey and Yin Jixiang. Philosophical Transactions of the Royal Society of London, Series A: Mathematical and Physical Sciences, 327(1594), p.203-213. Publisher: Royal Society of London, London, United Kingdom. ISSN: 0080-4614
Publication Date:1988
Note:In English. 25 refs.; illus. incl. 34 anal., 4 tables, geol. sketch maps
Summary:In the Lhasa terrain, the Nyainqentanglha orthogneiss bounded by staurolite-garnet schists to the N, records prograde metamorphism at 5.0 +- 1.3 kbar and 610 +- 70 degrees C. Garnet-sillimanite xenoliths in the orthogneiss indicate peak T <= 700 +- 70 degrees C at 5.1 +- 2.5 kbar. These results indicate high T/low P metamorphism during Eocene subduction and emplacement of orthogneiss at > 10 km depth. Amdo gneisses (N Lhasa terrain) contain sillimanite assemblages which indicate (?Cambrian or earlier) crustal anatexis at> 685 degrees C. In the Kunlun terrain, biotite and garnet isograds increase in grade from N to S, with a peak metamorphism at 470 +- 30 degrees C and 4.3 +- 1.5 kbar, and this was synchronous with the intrusion of the Triassic batholith. Regional metamorphism was followed by uplift of >= 2 km prior to intrusion of post-tectonic Jurassic granites. [R.K.H.]
Subjects:Chemical composition; Composition; Geochemistry; Gneisses; Major elements; Metamorphic rocks; Metamorphism; Metasedimentary rocks; P-T conditions; Petrology; Phyllites; Asia; China; Far East; Kunlun Mountains; Lhasa Block; Qiangtang Terrane; Tibetan Plateau; Xizang China; Evolution
Abstract Numbers:89M/3638
Record ID:1991008953
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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