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7560635 
Journal Article 
Tracing the origins of the western Himalaya: an isotopic comparison of the Nanga Parbat massif and Zanskar Himalaya 
Whittington, A; Harris, NBW; Ayres, MW; Foster, G; , 
2000 
GEOLOGICAL SOC PUBLISHING HOUSE 
BATH 
201-218 
WOS:000088015200011 
New Sr and Nd isotope data for basement gneisses and leucogranites are presented from two contrasting areas of the western Himalaya; the Nanga Parbat-Haramosh massif (NPHM) and Zanskar. Sr-isotope systematics of metapelites and anatectic migmatites from the Zanskar Himalaya are characterized by ss, of 515-930, typical of the High Himalayan Crystalline unit as exposed for more than 2000km along strike. Moreover, Zanskar leucogranites are typical of the belt of Early Miocene granites intruding the High Himalayan Crystallines across the orogen (mean epsilon(Sr), = 834). In contrast, the NPHM leucogranites show an elevated average epsilon(Sr) of 2400, and basement samples show a wide range in cs, from 1850 to 8150. Errorchrons for the metasedimentary gneisses indicate isotopic homogenization of the basement at c. 500 Ma for the Zanskar samples compared with c. 1800 Ma from the NPHM, confirming that the two terrains have experienced contrasting pre-Himalayan histories.Nd isotopic data from the NPHM indicate model ages from 2300 to 2800 Ma, indicating the mean crustal formation ages of the protoliths from which the sediments were derived. A compilation of published Nd data from the Himalaya indicates average protolith formation ages of 2640 +/- 270 Ma for the Lesser Himalaya lithologies, compared with 1940 +/- 370 Ma for the nigh Himalaya unit.Gneissic lithologies from Zanskar and the NPHM have previously been correlated with the High Himalayan Crystalline Series, since both display high-grade Himalayan metamorphism and are intruded by syn- to post-tectonic tourmaline-bearing leucogranites. Isotopic systematics in the Zanskar region confirm this correlation. In contrast, the NPHM basement rocks are better correlated with Lesser Himalayan lithologies, exposed south of the Main Central Thrust. We conclude that the NPHM represents either a lower structural level of the Lesser Himalaya Series, or its protolith. 
Khan, MA; Treloar, PJ; Searle, MP; Jan, MQ; 
1-86239-061-4 
13th Himalaya, Karakoram, Tibet Workshop on Tectonics of the Nanga Parbat Syntaxis and the Western Himalaya 
PESHAWAR, PAKISTAN 
PFAS
• PFNA