The Gangrinboche Conglomerate, exposed along the Yarlung-Zangbo suture zone, records a crucial stage of the Himalayan orogeny. The type section of these strata in the Xigaze area, southern Tibet, including the Qiuwu and Dazhuka Formations, was studied by integrated stratigraphic, sedimentologic, petrographic, and geochemical techniques. Palynological data and detrital zircon U-Pb ages indicate that the Qiuwu Formation was deposited during the latest Oligocene to the earliest Miocene (most probably ~23 Ma), while the overlying Dazhuka Formation was deposited during 23-18 Ma. The Qiuwu Formation was deposited in a deltaic setting, and detritus was entirely derived from the Gangdese magmatic arc in the north. The Dazhuka Formation, in contrast, was deposited in mainly braided river environments and contains clasts derived from both the Gangdese arc in the north and the Himalayan orogen in the south. Clasts derived from the south first occur at the base of the Dazhuka Formation and increase in abundance upsection to become predominant at the top of the formation. This indicates active Early Miocene uplift and accelerated erosion of the Himalayan belt. Paleocurrent data from the Dazhuka Formation show westward axial sediment transport, which together with mixed provenance from both sides of the basin indicates that a paleo-Yarlung-Zangbo River running parallel to the suture zone initiated at the very start of the Miocene, although with flow direction opposite to that of the present. Flow reversal and establishment of the modern eastward-flowing course must have occurred later on in the Neogene, possibly initiating rapid uplift and focused erosion of the Namche-Barwa syntaxis. Basin subsidence at the close of the Paleogene and subsequent development of a major longitudinal paleo-Yarlung-Zangbo took place contemporaneously with initiation of the South Tibetan Detachment System and Main Central Thrust farther to the south, probably reflecting onset of the "hard collision" phase of the Himalayan orogeny. © 2013 by The University of Chicago. All rights reserved.

Wang, J., Hu, X., Garzanti, E., Wu, F. (2013). Upper oligocene-lower miocene gangrinboche conglomerate in the Xigaze Area, Southern Tibet: Implications for Himalayan uplift and Paleo-Yarlung-Zangbo initiation. THE JOURNAL OF GEOLOGY, 121(4), 425-444 [10.1086/670722].

Upper oligocene-lower miocene gangrinboche conglomerate in the Xigaze Area, Southern Tibet: Implications for Himalayan uplift and Paleo-Yarlung-Zangbo initiation

GARZANTI, EDUARDO
Penultimo
;
2013

Abstract

The Gangrinboche Conglomerate, exposed along the Yarlung-Zangbo suture zone, records a crucial stage of the Himalayan orogeny. The type section of these strata in the Xigaze area, southern Tibet, including the Qiuwu and Dazhuka Formations, was studied by integrated stratigraphic, sedimentologic, petrographic, and geochemical techniques. Palynological data and detrital zircon U-Pb ages indicate that the Qiuwu Formation was deposited during the latest Oligocene to the earliest Miocene (most probably ~23 Ma), while the overlying Dazhuka Formation was deposited during 23-18 Ma. The Qiuwu Formation was deposited in a deltaic setting, and detritus was entirely derived from the Gangdese magmatic arc in the north. The Dazhuka Formation, in contrast, was deposited in mainly braided river environments and contains clasts derived from both the Gangdese arc in the north and the Himalayan orogen in the south. Clasts derived from the south first occur at the base of the Dazhuka Formation and increase in abundance upsection to become predominant at the top of the formation. This indicates active Early Miocene uplift and accelerated erosion of the Himalayan belt. Paleocurrent data from the Dazhuka Formation show westward axial sediment transport, which together with mixed provenance from both sides of the basin indicates that a paleo-Yarlung-Zangbo River running parallel to the suture zone initiated at the very start of the Miocene, although with flow direction opposite to that of the present. Flow reversal and establishment of the modern eastward-flowing course must have occurred later on in the Neogene, possibly initiating rapid uplift and focused erosion of the Namche-Barwa syntaxis. Basin subsidence at the close of the Paleogene and subsequent development of a major longitudinal paleo-Yarlung-Zangbo took place contemporaneously with initiation of the South Tibetan Detachment System and Main Central Thrust farther to the south, probably reflecting onset of the "hard collision" phase of the Himalayan orogeny. © 2013 by The University of Chicago. All rights reserved.
Articolo in rivista - Articolo scientifico
Geology; Himalaya;
English
2013
121
4
425
444
none
Wang, J., Hu, X., Garzanti, E., Wu, F. (2013). Upper oligocene-lower miocene gangrinboche conglomerate in the Xigaze Area, Southern Tibet: Implications for Himalayan uplift and Paleo-Yarlung-Zangbo initiation. THE JOURNAL OF GEOLOGY, 121(4), 425-444 [10.1086/670722].
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/72060
Citazioni
  • Scopus 62
  • ???jsp.display-item.citation.isi??? 56
Social impact