TY - JOUR
T1 - Triassic collision in the Paleo-Tethys Ocean constrained by volcanic activity in SW China
AU - Zi, Jian Wei
AU - Cawood, Peter A.
AU - Fan, Wei Ming
AU - Wang, Yue jun
AU - Tohver, Eric
AU - McCuaig, Thompson Campbell
AU - Peng, Tou Ping
PY - 2012/7
Y1 - 2012/7
N2 - A suite of collision-related Triassic volcanic rocks cropping out within the Jinshajiang-Ailaoshan orogenic belt in SW China offers insights into closure of the Paleo-Tethys and associated terrane/continent collision. Combined geochemical and Sr-Nd isotopic data for samples from the Jinshajiang segment demonstrate that the lower part of the volcanic suite is dominated by high-Si rhyolites (the Pantiange Formation) derived through crustal anatexis; whereas the upper units (the Cuiyibi Formation) are characterized by basalts alternating with intermediate-felsic lavas that share similar Sr-Nd isotopic signatures, and may have originated from partial melting of subduction-enriched lithospheric mantle. SHRIMP U-Pb analyses on zircons yield ages of 247-246. Ma for the rhyolites of the Pantiange Formation, and ages ranging from ca. 245. Ma to 237. Ma for the basaltic and intermediate-felsic samples from the overlying Cuiyibi Formation. These data, integrated with other geologic evidence (e.g., stratigraphic record), suggest an Early-Middle Triassic timing of terrane-continent collision along the Jinshajiang and Ailaoshan sutures with the 247-246. Ma Pantiange high-Si rhyolites representing the early magmatic products generated by this event. The development of the 245-237. Ma bimodal volcanism was associated with subsidence and deep-marine sedimentation. We interpret this as reflective of an extensional setting within an evolving collisional orogen, probably related to oblique convergence along the collisional zone. Triassic volcanic rocks with similar geochemical signatures and ages have been identified along the > 1000. km length of the Jinshajiang-Ailaoshan suture zone. The Indochina block to the south of the suture records 250-240. Ma tectonothermal activity. Taken together, these relationships suggest that initial collision and amalgamation of the Qamdo-Simao terrane (Indochina) with the Yangtze Block (South China) along the Jinshajiang-Ailaoshan and Song Ma sutures probably took place in the Early Triassic following consumption of the Paleo-Tethys Ocean.
AB - A suite of collision-related Triassic volcanic rocks cropping out within the Jinshajiang-Ailaoshan orogenic belt in SW China offers insights into closure of the Paleo-Tethys and associated terrane/continent collision. Combined geochemical and Sr-Nd isotopic data for samples from the Jinshajiang segment demonstrate that the lower part of the volcanic suite is dominated by high-Si rhyolites (the Pantiange Formation) derived through crustal anatexis; whereas the upper units (the Cuiyibi Formation) are characterized by basalts alternating with intermediate-felsic lavas that share similar Sr-Nd isotopic signatures, and may have originated from partial melting of subduction-enriched lithospheric mantle. SHRIMP U-Pb analyses on zircons yield ages of 247-246. Ma for the rhyolites of the Pantiange Formation, and ages ranging from ca. 245. Ma to 237. Ma for the basaltic and intermediate-felsic samples from the overlying Cuiyibi Formation. These data, integrated with other geologic evidence (e.g., stratigraphic record), suggest an Early-Middle Triassic timing of terrane-continent collision along the Jinshajiang and Ailaoshan sutures with the 247-246. Ma Pantiange high-Si rhyolites representing the early magmatic products generated by this event. The development of the 245-237. Ma bimodal volcanism was associated with subsidence and deep-marine sedimentation. We interpret this as reflective of an extensional setting within an evolving collisional orogen, probably related to oblique convergence along the collisional zone. Triassic volcanic rocks with similar geochemical signatures and ages have been identified along the > 1000. km length of the Jinshajiang-Ailaoshan suture zone. The Indochina block to the south of the suture records 250-240. Ma tectonothermal activity. Taken together, these relationships suggest that initial collision and amalgamation of the Qamdo-Simao terrane (Indochina) with the Yangtze Block (South China) along the Jinshajiang-Ailaoshan and Song Ma sutures probably took place in the Early Triassic following consumption of the Paleo-Tethys Ocean.
KW - Collisional orogenesis
KW - Jinshajiang orogenic belt
KW - Paleo-Tethys
KW - Triassic volcanism
UR - http://www.scopus.com/inward/record.url?scp=84860805528&partnerID=8YFLogxK
U2 - 10.1016/j.lithos.2012.04.020
DO - 10.1016/j.lithos.2012.04.020
M3 - Article
AN - SCOPUS:84860805528
VL - 144-145
SP - 145
EP - 160
JO - Lithos
JF - Lithos
SN - 0024-4937
ER -