Structural evolution of zonal metamorphic sequences in the southern Chinese Altai and relationships to Permian transpressional tectonics in the Central Asian Orogenic Belt

Li, Pengfei, Sun, Min, Rosenbaum, Gideon, Jiang, Yingde and Cai, Keda (2016) Structural evolution of zonal metamorphic sequences in the southern Chinese Altai and relationships to Permian transpressional tectonics in the Central Asian Orogenic Belt. Tectonophysics, 693 Part B: 277-289. doi:10.1016/j.tecto.2015.11.035


Author Li, Pengfei
Sun, Min
Rosenbaum, Gideon
Jiang, Yingde
Cai, Keda
Title Structural evolution of zonal metamorphic sequences in the southern Chinese Altai and relationships to Permian transpressional tectonics in the Central Asian Orogenic Belt
Journal name Tectonophysics   Check publisher's open access policy
ISSN 0040-1951
Publication date 2016-12-14
Year available 2015
Sub-type Article (original research)
DOI 10.1016/j.tecto.2015.11.035
Open Access Status Not yet assessed
Volume 693
Issue Part B
Start page 277
End page 289
Total pages 53
Place of publication Amsterdam, Netherlands
Publisher Elsevier
Language eng
Abstract The Chinese Altai in the Central Asian Orogenic Belt is characterized by the occurrence of kyanite-and andalusite-type metamorphic zones. However, the tectonic setting associated with these metamorphic zones is still debated. Here we present structural observations from the southern Chinese Altai (Aletai area), where a relict kyanite zone occurs within an andalusite-type metamorphic zonal sequence of sillimanite, andalusite-sillimanite, andalusite-staurolite, staurolite-garnet and biotite. We document two major phases of folding in this area. The earlier structures (D-1) developed synchronously with kyanite growth and are represented by an axial planar fabric of tight folds. D-1 fabric is mostly obliterated by later deformation, but is inferred to be penetrative as indicated by a profound intersection lineation (L-21). The second generation of deformation (D-2) is associated with superimposed F-2 folds and a dominant axial planar foliation (S-2) with similar to NW-SE orientation. Microstructural observations show that D-2 structures are associated with the andalusite-type metamorphic series, which is characterized by an early-D-2 occurrence of sillimanite, staurolite-garnet and biotite zonal sequence overprinted by the late-D-2 growth of andalusite. Combining with previous metamorphic data, we consider that these two folding events (D-1 and D-2) correspond with the development of kyanite- and andalusite-type metamorphic zones, respectively, which records the burial and exhumation history of metamorphic rocks possibly in response to Devonian-Carboniferous accretion/collision and Permian transpressional tectonics. The latter was associated with oblique convergence between the Chinese Altai and the intra-oceanic arc system of the East/West Junggar. (C) 2015 Elsevier B.V. All rights reserved.
Formatted abstract
The Chinese Altai in the Central Asian Orogenic Belt is characterized by the occurrence of kyanite- and andalusite-type metamorphic zones. However, the tectonic setting associated with these metamorphic zones is still debated. Here we present structural observations from the southern Chinese Altai (Aletai area), where a relict kyanite zone occurs within an andalusite-type metamorphic zonal sequence of sillimanite, andalusite-sillimanite, andalusite-staurolite, staurolite-garnet and biotite. We document two major phases of folding in this area. The earlier structures (D1) developed synchronously with kyanite growth and are represented by an axial planar fabric of tight folds. D1 fabric is mostly obliterated by later deformation, but is inferred to be penetrative as indicated by a profound intersection lineation (L21). The second generation of deformation (D2) is associated with superimposed F2 folds and a dominant axial planar foliation (S2) with ~ NW-SE orientation. Microstructural observations show that D2 structures are associated with the andalusite-type metamorphic series, which is characterized by an early-D2 occurrence of sillimanite, staurolite-garnet and biotite zonal sequence overprinted by the late-D2 growth of andalusite. Combining with previous metamorphic data, we consider that these two folding events (D1 and D2) correspond with the development of kyanite- and andalusite-type metamorphic zones, respectively, which records the burial and exhumation history of metamorphic rocks possibly in response to Devonian-Carboniferous accretion and Permian transpressional tectonics. The latter was associated with oblique convergence between the Chinese Altai and the intra-oceanic arc system of the East/West Junggar.
Keyword Chinese Altai
Central Asian Orogenic Belt
Kyanite
Andalusite
Q-Index Code C1
Q-Index Status Provisional Code
Grant ID 2014CB448000
HKU705311P
41273048
201309176226
Institutional Status UQ
Additional Notes Published online 30 December 2015. Article in press. Accepted manuscript

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Earth Sciences Publications
Official 2016 Collection
 
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Created: Mon, 04 Jan 2016, 17:50:09 EST by Dr Gideon Rosenbaum on behalf of School of Earth Sciences