TY - JOUR
T1 - The kinematic evolution of the Nepalese Himalaya interpreted from Nd isotopes
AU - Robinson, Delores M.
AU - DeCelles, Peter G.
AU - Patchett, P. Jonathan
AU - Garzione, Carmala N.
N1 - Funding Information:
Many thanks to Clark Isachsen and Jeff Vervoot for analytical instruction. John Chesley and Ofori Pearson provided fruitful discussions that improved our understanding of the data. The clarity of this manuscript was improved by reviews from Asish Basu and Scott McLennan. This project was supported by NSF grant EAR-9814060 to P.G.D. and P.J.P. D.M.R. was supported by the Geological Society of America, the Department of Geosciences at the University of Arizona, and donors to the Geostructures Partnership at the University of Arizona, including BP, Exxon, Conoco and Midland Valley Exploration. [AH]
PY - 2001
Y1 - 2001
N2 - Neodymium (Nd) isotopes from the Himalayan fold-thrust belt and its associated foreland basin deposits are useful for distinguishing between Himalayan tectonostratigraphic zones and revealing the erosional unroofing history as controlled by the kinematic development of the orogen. Neodymium isotopic data from the Himalayan fold-thrust belt in Nepal (n = 35) reveal that the Lesser Himalayan zone consistently has a more negative εNd(0) value than the Greater and Tibetan Himalayan zones. Our data show the average εNd(0) value in the Lesser Himalayan zone is - 21.5, whereas the Greater and Tibetan Himalayan zones have an average εNd(0) value of - 16. These consistently distinct values throughout Nepal enable the use of Nd isotopes as a technique for distinguishing between Lesser Himalayan zone and Greater Himalayan zone rock. The less negative εNd(0) values of the Greater Himalayan rocks support the idea that the Greater Himalayan zone is not Indian basement, but rather a terrane that accreted onto India during Early Paleozoic time. Neodymium isotopic data from Eocene through Pliocene foreland basin deposits (n = 34) show that sediment provenance has been dominated by Greater and Tibetan Himalayan detritus across Nepal. The εNd(T) values in the synorogenic rocks in western and central Nepal generally show an up-section shift toward more negative values and record the progressive unroofing of the different tectonostratigraphic zones. At Ο 10 Ma in Khutia Khola and Ο 11 Ma in Surai Khola, a shift in εNd(T) values from - 16 to - 18 marks the erosional breaching of a large duplex in the northern part of the Lesser Himalayan zone. This shift is not seen in eastern Nepal, where the εNd(T) values remain close to - 16 throughout Miocene time because there has been less erosional unroofing in this region.
AB - Neodymium (Nd) isotopes from the Himalayan fold-thrust belt and its associated foreland basin deposits are useful for distinguishing between Himalayan tectonostratigraphic zones and revealing the erosional unroofing history as controlled by the kinematic development of the orogen. Neodymium isotopic data from the Himalayan fold-thrust belt in Nepal (n = 35) reveal that the Lesser Himalayan zone consistently has a more negative εNd(0) value than the Greater and Tibetan Himalayan zones. Our data show the average εNd(0) value in the Lesser Himalayan zone is - 21.5, whereas the Greater and Tibetan Himalayan zones have an average εNd(0) value of - 16. These consistently distinct values throughout Nepal enable the use of Nd isotopes as a technique for distinguishing between Lesser Himalayan zone and Greater Himalayan zone rock. The less negative εNd(0) values of the Greater Himalayan rocks support the idea that the Greater Himalayan zone is not Indian basement, but rather a terrane that accreted onto India during Early Paleozoic time. Neodymium isotopic data from Eocene through Pliocene foreland basin deposits (n = 34) show that sediment provenance has been dominated by Greater and Tibetan Himalayan detritus across Nepal. The εNd(T) values in the synorogenic rocks in western and central Nepal generally show an up-section shift toward more negative values and record the progressive unroofing of the different tectonostratigraphic zones. At Ο 10 Ma in Khutia Khola and Ο 11 Ma in Surai Khola, a shift in εNd(T) values from - 16 to - 18 marks the erosional breaching of a large duplex in the northern part of the Lesser Himalayan zone. This shift is not seen in eastern Nepal, where the εNd(T) values remain close to - 16 throughout Miocene time because there has been less erosional unroofing in this region.
KW - Himalayas
KW - Nd-144/Nd-143
KW - Nepal
KW - Provenance
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U2 - 10.1016/S0012-821X(01)00451-4
DO - 10.1016/S0012-821X(01)00451-4
M3 - Article
AN - SCOPUS:0035199044
VL - 192
SP - 507
EP - 521
JO - Earth and Planetary Sciences Letters
JF - Earth and Planetary Sciences Letters
SN - 0012-821X
IS - 4
ER -