Kinematics and age constraints of deformation in a Late Carboniferous accretionary complex in Western Junggar, NW China

Ji'en ZHANG, Wenjiao XIAO*, Chunming HAN, Songjian AO, Chao YUAN, Min SUN, Hongyan GENG, Guochun ZHAO, Qianqian GUO, Chong MA

*Corresponding author for this work

Research output: Journal PublicationsJournal Article (refereed)Researchpeer-review

125 Citations (Scopus)

Abstract

The Karamay area, situated in the eastern part of Western Junggar, Southern Altaids, contains an ophiolitic mélange with ultramafic rocks, gabbro, basalt, chert and limestone, which show typical block-in-matrix structures, and coherent turbidites and tuffs. These lithological associations are interpreted as incoherent and coherent series formed in an accretionary complex. On the basis of detailed field mapping and analyses of the asymmetry of imbricate thrusts, duplexes, tilted structures, shear band cleavages, and the NW-verging inclined to overturned folds, we conclude that the overall movement in the accretionary complex was top-to-the-NW. The youngest tuff involved in the deformation contains detrital zircons that have a U-Pb age (LA-MC ICP-MS) of 308±7Ma. 39Ar-40Ar resistance furnace step-heating of amphibole separates from a diorite dike, which cuts the folded and imbricated rocks in the accretionary prism, yielded a plateau age of 307±2Ma. Consequently, the age of the deformation in the prism is tightly constrained at 307-308Ma, implying that the deformation occurred in an extremely short time-span during SE-ward subduction. Combined contemporaneous occurrence of Baogutu adakite, high-Mg, Sr-enriched and Y-poor dioritic dikes, Miaoergou charnockite, and Maliya mafic rocks, we further suggest the accretionary complex was cut by near-trench volcanic rocks and plutons possibly due to interaction with a spreading ridge.

Original languageEnglish
Pages (from-to)958-974
Number of pages17
JournalGondwana Research
Volume19
Issue number4
Early online date17 Oct 2010
DOIs
Publication statusPublished - Jun 2011
Externally publishedYes

Fingerprint

kinematics
dike
adakite
charnockite
shear band
duplex
accretionary prism
chert
ultramafic rock
diorite
mafic rock
tuff
gabbro
amphibole
cleavage
pluton
trench
asymmetry
volcanic rock
zircon

Keywords

  • Accretionary complex
  • Coheret unit
  • Melange
  • Southern Altaids
  • West Junggar

Cite this

ZHANG, Ji'en ; XIAO, Wenjiao ; HAN, Chunming ; AO, Songjian ; YUAN, Chao ; SUN, Min ; GENG, Hongyan ; ZHAO, Guochun ; GUO, Qianqian ; MA, Chong. / Kinematics and age constraints of deformation in a Late Carboniferous accretionary complex in Western Junggar, NW China. In: Gondwana Research. 2011 ; Vol. 19, No. 4. pp. 958-974.
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abstract = "The Karamay area, situated in the eastern part of Western Junggar, Southern Altaids, contains an ophiolitic m{\'e}lange with ultramafic rocks, gabbro, basalt, chert and limestone, which show typical block-in-matrix structures, and coherent turbidites and tuffs. These lithological associations are interpreted as incoherent and coherent series formed in an accretionary complex. On the basis of detailed field mapping and analyses of the asymmetry of imbricate thrusts, duplexes, tilted structures, shear band cleavages, and the NW-verging inclined to overturned folds, we conclude that the overall movement in the accretionary complex was top-to-the-NW. The youngest tuff involved in the deformation contains detrital zircons that have a U-Pb age (LA-MC ICP-MS) of 308±7Ma. 39Ar-40Ar resistance furnace step-heating of amphibole separates from a diorite dike, which cuts the folded and imbricated rocks in the accretionary prism, yielded a plateau age of 307±2Ma. Consequently, the age of the deformation in the prism is tightly constrained at 307-308Ma, implying that the deformation occurred in an extremely short time-span during SE-ward subduction. Combined contemporaneous occurrence of Baogutu adakite, high-Mg, Sr-enriched and Y-poor dioritic dikes, Miaoergou charnockite, and Maliya mafic rocks, we further suggest the accretionary complex was cut by near-trench volcanic rocks and plutons possibly due to interaction with a spreading ridge.",
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Kinematics and age constraints of deformation in a Late Carboniferous accretionary complex in Western Junggar, NW China. / ZHANG, Ji'en; XIAO, Wenjiao; HAN, Chunming; AO, Songjian; YUAN, Chao; SUN, Min; GENG, Hongyan; ZHAO, Guochun; GUO, Qianqian; MA, Chong.

In: Gondwana Research, Vol. 19, No. 4, 06.2011, p. 958-974.

Research output: Journal PublicationsJournal Article (refereed)Researchpeer-review

TY - JOUR

T1 - Kinematics and age constraints of deformation in a Late Carboniferous accretionary complex in Western Junggar, NW China

AU - ZHANG, Ji'en

AU - XIAO, Wenjiao

AU - HAN, Chunming

AU - AO, Songjian

AU - YUAN, Chao

AU - SUN, Min

AU - GENG, Hongyan

AU - ZHAO, Guochun

AU - GUO, Qianqian

AU - MA, Chong

PY - 2011/6

Y1 - 2011/6

N2 - The Karamay area, situated in the eastern part of Western Junggar, Southern Altaids, contains an ophiolitic mélange with ultramafic rocks, gabbro, basalt, chert and limestone, which show typical block-in-matrix structures, and coherent turbidites and tuffs. These lithological associations are interpreted as incoherent and coherent series formed in an accretionary complex. On the basis of detailed field mapping and analyses of the asymmetry of imbricate thrusts, duplexes, tilted structures, shear band cleavages, and the NW-verging inclined to overturned folds, we conclude that the overall movement in the accretionary complex was top-to-the-NW. The youngest tuff involved in the deformation contains detrital zircons that have a U-Pb age (LA-MC ICP-MS) of 308±7Ma. 39Ar-40Ar resistance furnace step-heating of amphibole separates from a diorite dike, which cuts the folded and imbricated rocks in the accretionary prism, yielded a plateau age of 307±2Ma. Consequently, the age of the deformation in the prism is tightly constrained at 307-308Ma, implying that the deformation occurred in an extremely short time-span during SE-ward subduction. Combined contemporaneous occurrence of Baogutu adakite, high-Mg, Sr-enriched and Y-poor dioritic dikes, Miaoergou charnockite, and Maliya mafic rocks, we further suggest the accretionary complex was cut by near-trench volcanic rocks and plutons possibly due to interaction with a spreading ridge.

AB - The Karamay area, situated in the eastern part of Western Junggar, Southern Altaids, contains an ophiolitic mélange with ultramafic rocks, gabbro, basalt, chert and limestone, which show typical block-in-matrix structures, and coherent turbidites and tuffs. These lithological associations are interpreted as incoherent and coherent series formed in an accretionary complex. On the basis of detailed field mapping and analyses of the asymmetry of imbricate thrusts, duplexes, tilted structures, shear band cleavages, and the NW-verging inclined to overturned folds, we conclude that the overall movement in the accretionary complex was top-to-the-NW. The youngest tuff involved in the deformation contains detrital zircons that have a U-Pb age (LA-MC ICP-MS) of 308±7Ma. 39Ar-40Ar resistance furnace step-heating of amphibole separates from a diorite dike, which cuts the folded and imbricated rocks in the accretionary prism, yielded a plateau age of 307±2Ma. Consequently, the age of the deformation in the prism is tightly constrained at 307-308Ma, implying that the deformation occurred in an extremely short time-span during SE-ward subduction. Combined contemporaneous occurrence of Baogutu adakite, high-Mg, Sr-enriched and Y-poor dioritic dikes, Miaoergou charnockite, and Maliya mafic rocks, we further suggest the accretionary complex was cut by near-trench volcanic rocks and plutons possibly due to interaction with a spreading ridge.

KW - Accretionary complex

KW - Coheret unit

KW - Melange

KW - Southern Altaids

KW - West Junggar

UR - http://www.scopus.com/inward/record.url?scp=79954632194&partnerID=8YFLogxK

U2 - 10.1016/j.gr.2010.10.003

DO - 10.1016/j.gr.2010.10.003

M3 - Journal Article (refereed)

VL - 19

SP - 958

EP - 974

JO - Gondwana Research

JF - Gondwana Research

SN - 1342-937X

IS - 4

ER -