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Evolution of the melt source during protracted crustal anatexis: an example from the Bhutan Himalaya

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Evolution of the melt source during protracted crustal anatexis: an example from the Bhutan Himalaya. / Hopkinson, Thomas; Harris, Nigel; Roberts, Nick M. W.; Warren, Clare J.; Hammond, Sam; Spencer, Christopher J.; Parrish, Randall R.

In: Geology, Vol. 48, No. 1, 01.01.2020, p. 87-91.

Research output: Contribution to journalArticle

Harvard

Hopkinson, T, Harris, N, Roberts, NMW, Warren, CJ, Hammond, S, Spencer, CJ & Parrish, RR 2020, 'Evolution of the melt source during protracted crustal anatexis: an example from the Bhutan Himalaya', Geology, vol. 48, no. 1, pp. 87-91. https://doi.org/10.1130/G47078.1

APA

Hopkinson, T., Harris, N., Roberts, N. M. W., Warren, C. J., Hammond, S., Spencer, C. J., & Parrish, R. R. (2020). Evolution of the melt source during protracted crustal anatexis: an example from the Bhutan Himalaya. Geology, 48(1), 87-91. https://doi.org/10.1130/G47078.1

Vancouver

Hopkinson T, Harris N, Roberts NMW, Warren CJ, Hammond S, Spencer CJ et al. Evolution of the melt source during protracted crustal anatexis: an example from the Bhutan Himalaya. Geology. 2020 Jan 1;48(1):87-91. https://doi.org/10.1130/G47078.1

Author

Hopkinson, Thomas ; Harris, Nigel ; Roberts, Nick M. W. ; Warren, Clare J. ; Hammond, Sam ; Spencer, Christopher J. ; Parrish, Randall R. / Evolution of the melt source during protracted crustal anatexis: an example from the Bhutan Himalaya. In: Geology. 2020 ; Vol. 48, No. 1. pp. 87-91.

Bibtex

@article{d73455f54e70497e914b464baa5788d1,
title = "Evolution of the melt source during protracted crustal anatexis: an example from the Bhutan Himalaya",
abstract = "The chemical compositions of magmatic zircon growth zones provide powerful insight into evolving magma compositions due to their ability to record both time and the local chemical environment. In situ U-Pb and Hf isotope analyses of zircon rims from Oligocene–Miocene leucogranites of the Bhutan Himalaya reveal, for the first time, an evolution in melt composition between 32 and 12 Ma. The data indicate a uniform melt source from 32 Ma to 17 Ma, and the progressive addition of an older source component to the melt from at least ca. 17 Ma. Age-corrected ɛHf ratios decrease from between −10 and −15 down to values as low as −23 by 12 Ma. Complementary whole-rock Nd isotope data corroborate the Hf data, with a progressive decrease in ɛNd(t) from ca. 18 to 12 Ma. Published zircon and whole-rock Nd data from different lithotectonic units in the Himalaya suggest a chemical distinction between the younger Greater Himalayan Series (GHS) and the older Lesser Himalayan Series (LHS). The time-dependent isotopic evolution shown in the leucogranites demonstrates a progressive increase in melt contribution from older lithologies, suggestive of increasing LHS involvement in Himalayan melting over time. The time-resolved data are consistent with LHS material being progressively accreted to the base of the GHS from ca. 17 Ma, facilitated by deformation along the Main Central thrust. From 17 Ma, decompression, which had triggered anatexis in the GHS since the Paleogene, enabled melting in older sources from the accreted LHS, now forming the lowermost hanging wall of the thrust.",
author = "Thomas Hopkinson and Nigel Harris and Roberts, {Nick M. W.} and Warren, {Clare J.} and Sam Hammond and Spencer, {Christopher J.} and Parrish, {Randall R.}",
year = "2020",
month = "1",
day = "1",
doi = "10.1130/G47078.1",
language = "English",
volume = "48",
pages = "87--91",
journal = "Geology",
issn = "0091-7613",
publisher = "Geological Society of America",
number = "1",

}

RIS

TY - JOUR

T1 - Evolution of the melt source during protracted crustal anatexis: an example from the Bhutan Himalaya

AU - Hopkinson, Thomas

AU - Harris, Nigel

AU - Roberts, Nick M. W.

AU - Warren, Clare J.

AU - Hammond, Sam

AU - Spencer, Christopher J.

AU - Parrish, Randall R.

PY - 2020/1/1

Y1 - 2020/1/1

N2 - The chemical compositions of magmatic zircon growth zones provide powerful insight into evolving magma compositions due to their ability to record both time and the local chemical environment. In situ U-Pb and Hf isotope analyses of zircon rims from Oligocene–Miocene leucogranites of the Bhutan Himalaya reveal, for the first time, an evolution in melt composition between 32 and 12 Ma. The data indicate a uniform melt source from 32 Ma to 17 Ma, and the progressive addition of an older source component to the melt from at least ca. 17 Ma. Age-corrected ɛHf ratios decrease from between −10 and −15 down to values as low as −23 by 12 Ma. Complementary whole-rock Nd isotope data corroborate the Hf data, with a progressive decrease in ɛNd(t) from ca. 18 to 12 Ma. Published zircon and whole-rock Nd data from different lithotectonic units in the Himalaya suggest a chemical distinction between the younger Greater Himalayan Series (GHS) and the older Lesser Himalayan Series (LHS). The time-dependent isotopic evolution shown in the leucogranites demonstrates a progressive increase in melt contribution from older lithologies, suggestive of increasing LHS involvement in Himalayan melting over time. The time-resolved data are consistent with LHS material being progressively accreted to the base of the GHS from ca. 17 Ma, facilitated by deformation along the Main Central thrust. From 17 Ma, decompression, which had triggered anatexis in the GHS since the Paleogene, enabled melting in older sources from the accreted LHS, now forming the lowermost hanging wall of the thrust.

AB - The chemical compositions of magmatic zircon growth zones provide powerful insight into evolving magma compositions due to their ability to record both time and the local chemical environment. In situ U-Pb and Hf isotope analyses of zircon rims from Oligocene–Miocene leucogranites of the Bhutan Himalaya reveal, for the first time, an evolution in melt composition between 32 and 12 Ma. The data indicate a uniform melt source from 32 Ma to 17 Ma, and the progressive addition of an older source component to the melt from at least ca. 17 Ma. Age-corrected ɛHf ratios decrease from between −10 and −15 down to values as low as −23 by 12 Ma. Complementary whole-rock Nd isotope data corroborate the Hf data, with a progressive decrease in ɛNd(t) from ca. 18 to 12 Ma. Published zircon and whole-rock Nd data from different lithotectonic units in the Himalaya suggest a chemical distinction between the younger Greater Himalayan Series (GHS) and the older Lesser Himalayan Series (LHS). The time-dependent isotopic evolution shown in the leucogranites demonstrates a progressive increase in melt contribution from older lithologies, suggestive of increasing LHS involvement in Himalayan melting over time. The time-resolved data are consistent with LHS material being progressively accreted to the base of the GHS from ca. 17 Ma, facilitated by deformation along the Main Central thrust. From 17 Ma, decompression, which had triggered anatexis in the GHS since the Paleogene, enabled melting in older sources from the accreted LHS, now forming the lowermost hanging wall of the thrust.

U2 - 10.1130/G47078.1

DO - 10.1130/G47078.1

M3 - Article

VL - 48

SP - 87

EP - 91

JO - Geology

JF - Geology

SN - 0091-7613

IS - 1

ER -

ID: 18838020