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Late Triassic volcanic activity in South-East Asia: New stratigraphical, geochronological and paleontological evidence from the Luang Prabang Basin (Laos)

Blanchard, Sebastien ; Rossignol, Camille ; Bourquin, Sylvie ; Dabard, Marie-Pierre ; Hallot, Erwan ; Nalpas, Thierry ; Poujol, Marc ; Battail, Bernard ; Jalil, Nour-Eddine and Steyer, Jean-Sebastien , et al. (2013) In Journal of Asian Earth Sciences 70-71. p.8-26
Abstract
In South-East Asia, sedimentary basins displaying continental Permian and Triassic deposits have been poorly studied. Among these, the Luang Prabang Basin (North Laos) represents a potential key target to constrain the stratigraphic and structural evolutions of South-East Asia. A combined approach involving sedimentology, palaeontology, geochronology and structural analysis, was thus implemented to study the basin. It resulted in a new geological map, in defining new formations, and in proposing a complete revision of the Late Permian to Triassic stratigraphic succession as well as of the structural organization of the basin. Radiometric ages are used to discuss the synchronism of volcanic activity and sedimentation. The Luang Prabang... (More)
In South-East Asia, sedimentary basins displaying continental Permian and Triassic deposits have been poorly studied. Among these, the Luang Prabang Basin (North Laos) represents a potential key target to constrain the stratigraphic and structural evolutions of South-East Asia. A combined approach involving sedimentology, palaeontology, geochronology and structural analysis, was thus implemented to study the basin. It resulted in a new geological map, in defining new formations, and in proposing a complete revision of the Late Permian to Triassic stratigraphic succession as well as of the structural organization of the basin. Radiometric ages are used to discuss the synchronism of volcanic activity and sedimentation. The Luang Prabang Basin consists of an asymmetric NE-SW syncline with NE-SW thrusts, located at the contact between Late Permian and Late Triassic deposits. The potential stratigraphic gap at the Permian-Triassic boundary is therefore masked by deformation in the basin. The Late Triassic volcaniclastic continental deposits are representative of alluvial plain and fluvial environments. The basin was fed by several sources, varying from volcanic, carbonated to silicic (non-volcanic). U-Pb dating of euhedral zircon grains provided maximum sedimentation ages. The stratigraphic vertical succession of these ages, from ca. 225, ca. 220 to ca. 216 Ma, indicates that a long lasting volcanism was active during sedimentation and illustrates significant variations in sediment preservation rates in continental environments (from similar to 100 m/Ma to similar to 3 m/Ma). Anhedral inherited zircon grains gave older ages. A large number of them, at ca. 1870 Ma, imply the reworking of a Proterozoic basement and/or of sediments containing fragments of such a basement. In addition, the Late Triassic (Carnian to Norian) sediments yielded to a new dicynodont skull, attributed to the Kannemeyeriiform group family, from layers dated in between similar to 225 and similar to 221 Ma (Carnian). (C) 2013 Elsevier Ltd. All rights reserved. (Less)
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type
Contribution to journal
publication status
published
subject
keywords
Luang Prabang Basin, Permian, Triassic, Volcaniclastic continental, deposits, Kannemeyeriiformes, Dicynodont, U-Pb geochronology
in
Journal of Asian Earth Sciences
volume
70-71
pages
8 - 26
publisher
Elsevier
external identifiers
  • wos:000320076600002
  • scopus:84879883464
ISSN
1367-9120
DOI
10.1016/j.jseaes.2013.02.024
language
English
LU publication?
yes
id
c6b6be4d-2f6d-4952-a93a-ab9943aa7129 (old id 3987211)
date added to LUP
2016-04-01 11:14:54
date last changed
2020-04-07 01:53:05
@article{c6b6be4d-2f6d-4952-a93a-ab9943aa7129,
  abstract     = {In South-East Asia, sedimentary basins displaying continental Permian and Triassic deposits have been poorly studied. Among these, the Luang Prabang Basin (North Laos) represents a potential key target to constrain the stratigraphic and structural evolutions of South-East Asia. A combined approach involving sedimentology, palaeontology, geochronology and structural analysis, was thus implemented to study the basin. It resulted in a new geological map, in defining new formations, and in proposing a complete revision of the Late Permian to Triassic stratigraphic succession as well as of the structural organization of the basin. Radiometric ages are used to discuss the synchronism of volcanic activity and sedimentation. The Luang Prabang Basin consists of an asymmetric NE-SW syncline with NE-SW thrusts, located at the contact between Late Permian and Late Triassic deposits. The potential stratigraphic gap at the Permian-Triassic boundary is therefore masked by deformation in the basin. The Late Triassic volcaniclastic continental deposits are representative of alluvial plain and fluvial environments. The basin was fed by several sources, varying from volcanic, carbonated to silicic (non-volcanic). U-Pb dating of euhedral zircon grains provided maximum sedimentation ages. The stratigraphic vertical succession of these ages, from ca. 225, ca. 220 to ca. 216 Ma, indicates that a long lasting volcanism was active during sedimentation and illustrates significant variations in sediment preservation rates in continental environments (from similar to 100 m/Ma to similar to 3 m/Ma). Anhedral inherited zircon grains gave older ages. A large number of them, at ca. 1870 Ma, imply the reworking of a Proterozoic basement and/or of sediments containing fragments of such a basement. In addition, the Late Triassic (Carnian to Norian) sediments yielded to a new dicynodont skull, attributed to the Kannemeyeriiform group family, from layers dated in between similar to 225 and similar to 221 Ma (Carnian). (C) 2013 Elsevier Ltd. All rights reserved.},
  author       = {Blanchard, Sebastien and Rossignol, Camille and Bourquin, Sylvie and Dabard, Marie-Pierre and Hallot, Erwan and Nalpas, Thierry and Poujol, Marc and Battail, Bernard and Jalil, Nour-Eddine and Steyer, Jean-Sebastien and Vacant, Renaud and Veran, Monette and Bercovici, Antoine and Bienvenido Diez, Jose and Paquette, Jean-Louis and Khenthavong, Bounxou and Vongphamany, Sotsy},
  issn         = {1367-9120},
  language     = {eng},
  pages        = {8--26},
  publisher    = {Elsevier},
  series       = {Journal of Asian Earth Sciences},
  title        = {Late Triassic volcanic activity in South-East Asia: New stratigraphical, geochronological and paleontological evidence from the Luang Prabang Basin (Laos)},
  url          = {http://dx.doi.org/10.1016/j.jseaes.2013.02.024},
  doi          = {10.1016/j.jseaes.2013.02.024},
  volume       = {70-71},
  year         = {2013},
}