Constraining the timing of early topographic growth on the Tibetan plateau is critical for any models of India-Asia collision, Himalayan orogeny and subsequent plateau development in the Cenozoic. Stratigraphic, sedimentological and provenance analysis of the Lower Cretaceous red-beds of the Damxung Conglomerate provide new key information to reconstruct the paleogeography and the tectonic evolution of the Lhasa terrane at the time. The over 700-m-thick Damxung Conglomerate documents distal alluvial fan to braidplain sedimentation passing upward to proximal alluvial fan sedimentation. Deposition began near sea level, as documented by limestone beds occurring at the base of the unit. Zircon U–Pb dating of interbedded tuff layers constrain deposition age at ca. 111 Ma. Abundance of volcanic clasts, Cretaceous U–Pb ages and Hf isotopes of detrital zircons yielding mainly negative εHf(t) values together with paleocurrent data indicate an active volcanic source located in the North Lhasa subterrane. Pre-Mesozoic-aged zircon, recycled quartz and (meta) sedimentary rock fragments increase up-section, indicating progressive erosional exhumation of the Paleozoic sedimentary/metasedimentary basement. The Damxung Conglomerate thus records a significant uplift and unroofing stage in the source region, implying initial topographic growth on the Lhasa terrane at early Albian time. Early Cretaceous topographic growth on the Lhasa terrane is supported by the stratigraphic record in the Linzhou basin, the Xigaze forearc basin and the southern Nima basin. In contrast, marine strata in the central-western Lhasa terrane lasted until the early Cenomanian (ca. 96 Ma), indicating diachronous marine regression on the Lhasa terrane from east to west.

Wang, J., Hu, X., Garzanti, E., Ji, W., Liu, Z., Liu, X., et al. (2017). Early cretaceous topographic growth of the Lhasaplano, Tibetan plateau: Constraints from the Damxung conglomerate. JOURNAL OF GEOPHYSICAL RESEARCH. SOLID EARTH, 122(7), 5748-5765 [10.1002/2017JB014278].

Early cretaceous topographic growth of the Lhasaplano, Tibetan plateau: Constraints from the Damxung conglomerate

Garzanti E.;
2017

Abstract

Constraining the timing of early topographic growth on the Tibetan plateau is critical for any models of India-Asia collision, Himalayan orogeny and subsequent plateau development in the Cenozoic. Stratigraphic, sedimentological and provenance analysis of the Lower Cretaceous red-beds of the Damxung Conglomerate provide new key information to reconstruct the paleogeography and the tectonic evolution of the Lhasa terrane at the time. The over 700-m-thick Damxung Conglomerate documents distal alluvial fan to braidplain sedimentation passing upward to proximal alluvial fan sedimentation. Deposition began near sea level, as documented by limestone beds occurring at the base of the unit. Zircon U–Pb dating of interbedded tuff layers constrain deposition age at ca. 111 Ma. Abundance of volcanic clasts, Cretaceous U–Pb ages and Hf isotopes of detrital zircons yielding mainly negative εHf(t) values together with paleocurrent data indicate an active volcanic source located in the North Lhasa subterrane. Pre-Mesozoic-aged zircon, recycled quartz and (meta) sedimentary rock fragments increase up-section, indicating progressive erosional exhumation of the Paleozoic sedimentary/metasedimentary basement. The Damxung Conglomerate thus records a significant uplift and unroofing stage in the source region, implying initial topographic growth on the Lhasa terrane at early Albian time. Early Cretaceous topographic growth on the Lhasa terrane is supported by the stratigraphic record in the Linzhou basin, the Xigaze forearc basin and the southern Nima basin. In contrast, marine strata in the central-western Lhasa terrane lasted until the early Cenomanian (ca. 96 Ma), indicating diachronous marine regression on the Lhasa terrane from east to west.
Articolo in rivista - Articolo scientifico
alluvial fan conglomerate; early cretaceous; Lhasa block; tectonic uplift; Tibetan plateau
English
2017
122
7
5748
5765
none
Wang, J., Hu, X., Garzanti, E., Ji, W., Liu, Z., Liu, X., et al. (2017). Early cretaceous topographic growth of the Lhasaplano, Tibetan plateau: Constraints from the Damxung conglomerate. JOURNAL OF GEOPHYSICAL RESEARCH. SOLID EARTH, 122(7), 5748-5765 [10.1002/2017JB014278].
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/10281/269369
Citazioni
  • Scopus 41
  • ???jsp.display-item.citation.isi??? 29
Social impact