Detrital zircon record of Cambrian (meta‐)sedimentary strata in the western part of the Baoshan Block: Constraints on its eastern boundary and Early Palaeozoic palaeoposition. (26th July 2019)

• Record Type: Journal Article
• Authors: Xu, Benyan; Li, Dapeng; Kang, Huan; Song, Lijun; Chen, Yuelong; Zhang, Yulong; Geng, Jianzhen
• Editors: Somerville, I.
• Is Part Of: Geological journal. Volume 55:Number 5(2020)
• Page Start: 3416
• Page End: 3429
• Publication Date: 2019-07-26
• Subjects: detrital zircon -- eastern Gondwana -- Hf isotopes -- Tibetan plateau -- U–Pb ages; Geology -- Periodicals; 551
• DOI: 10.1002/gj.3593
• Languages: English
• ISSNs: 0072-1050

Abstract

Abstract : The premise to discuss the evolution of an orogenic belt is to understand the origins and tectonic affinities of various blocks that constitute the orogen. The Baoshan Block in the SE Tibetan Plateau is an ultimate window to observe the orogenic evolution, but its origin and eastern boundary remains debated. In this contribution, we report new detrital zircon U–Pb ages and Hf isotopic data from the Cambrian Baoshan Formation in the middle–western part of the Baoshan Block. Detrital zircon ages range from the Archean to Early Palaeozoic, with age peaks at ~2.5, ~0.95, and ~0.55 Ga. Zircon ε Hf (t) values exhibit a wide range from negative to positive for each of the three major age groups, indicating diverse magma sources. The eastern boundary for the Baoshan Block should be extended from the Kejie‐Nandinghe Fault to the Changning‐Menglian suture belt, based on not only comparisons of Early Palaeozoic magmatism, sedimentary facies, and provenances for the Palaeozoic strata that developed on both sides of the Kejie‐Nandinghe Fault but also on the regional tectonic framework correlation. The Baoshan Block should be along the Indian margin as the Qiangtang, Tengchong, and Simao‐Indochina blocks in Early Palaeozoic according to the provenance analyses.