Skip to Main content Skip to Navigation
Journal articles

Petrology and geochemistry of Early Permian volcanic rocks in South Tian Shan, NW China: implications for the tectonic evolution and Phanerozoic continental growth

Abstract : Situated in the southwest of the Central Asian Orogenic Belt (CAOB), the South Tian Shan (STS) Block is a key area for understanding the final accretion of the CAOB. A suite of volcanic rocks interbedded with continental sediments from the Xiaotikanlike Formation lies along the southwestern edge of the Tian Shan orogen. Laser-ablation-inductively coupled plasma-mass spectrometer U–Pb dating provided a crystallization age of 295.0 ± 2.8 Ma (MSWD = 1.3), suggesting an Early Permian magmatic event. The volcanic rocks show a variable composition, with dominant rhyolites and dacites, subordinate basaltic andesites and few basalts. The felsic rocks are enriched in K and exhibit remarkably negative anomalies in Ba, Sr, Eu, P and Ti. These anomalies associated with their high negative !Nd(t) values and old Nd model ages suggest that they are most likely sourced from ancient lower crustal rocks. The mafic rocks are characterized by high Mg#, Cr, Ni contents, negative Nb, Ta anomalies and pronounced enrichment in light rare earth elements as well as mild enrichment in large-ion lithophile elements. The mafic rocks are thus inferred to derive from enriched subcontinental lithospheric mantle. The petrographic and geochemical characteristics of the Xiaotikanlike Formation volcanic rocks indicate that they were generated under a post-collisional regime. Therefore, the final collision between the Tarim Craton and the Kazakhstan– Yili terrane took place before Early Permian, most probably at Late Carboniferous. Differing from other tectonic units of the CAOB, the recycling of ancient lithospheric crust played a significant role in the continental growth of the STS Block.
Document type :
Journal articles
Complete list of metadatas

https://hal-insu.archives-ouvertes.fr/insu-01119357
Contributor : Isabelle Dubigeon <>
Submitted on : Monday, February 23, 2015 - 9:40:52 AM
Last modification on : Monday, June 15, 2020 - 1:38:03 PM

Identifiers

Collections

Citation

Dongdong Liu, Zhaojie Guo, Marc Jolivet, Feng Cheng, Yan Song, et al.. Petrology and geochemistry of Early Permian volcanic rocks in South Tian Shan, NW China: implications for the tectonic evolution and Phanerozoic continental growth. International Journal of Earth Sciences, Springer Verlag, 2014, 10, 103 (3), pp.737-756. ⟨10.1007/s00531-013-0994-1⟩. ⟨insu-01119357⟩

Share

Metrics

Record views

209