Linking south China to northern Australia and India on the margin of Gondwana: Constraints from detrital zircon U-Pb and Hf isotopes in Cambrian strata

Abstract

Cambrian sedimentary rocks in the southern part of the South China Craton were derived from a source that lay to the south or southeast, beyond the current limits of the craton and which is no longer preserved nearby. U‐Pb ages and Hf isotope data on detrital zircons from the Cambrian sequence define two distinctive age peaks at 1120 Ma and 960 Ma, with εHf(t) values for each group identical to the coeval detrital zircons from Western Australia and the Tethyan Himalaya zone, respectively. The circa 1120 Ma detrital zircons were most likely derived from the Wilkes‐Albany‐Fraser belt between southwest Australia and Antarctica, whereas the circa 960 Ma detrital zircons could have been sourced from the Rayner‐Eastern Ghats belt between India and Antarctica. Derivation of detritus from these sources suggests that south China was located at the nexus between India, Antarctica, and Australia, along the northern margin of East Gondwana during the Cambrian.

Where was the Ailaoshan Ocean and when did it open: A perspective based on detrital zircon U–Pb age and Hf isotope evidence

“…Previous studies on lower Paleozoic detrital sedimenatry rocks in the South China Block have also found abundant detrital zircons with Pan-African age and concluded that the South China Block should be linked with and received detritus from North India and Western Australia during the assembly of East Gondwana. Our new data is consistent with and provided more evidence for this conclusion Xu et al, 2013;Zhou et al, 2015).…”

“…Previous detrital zircon data have also shown that Neoproterozoic zircons have both positive and negative εHf(t) values (e.g. Dong et al, 2011;Duan et al, 2011;Wang et al, 2012;Xu et al, 2013;Q.F. Wang et al, 2014;Zhou et al, 2015).…”

“…8), implying reworking of older crustal material. Although no igneous rocks with 530-650 Ma have yet been identified in South China, abundant detrital zircons of this age have been widely reported in Upper Neoproterozoic to Cambrian sequence in both the Yangtze and Cathaysia blocks Xu et al, 2013;Zhou et al, 2015). These sedimentary rocks can supply the detrital zircons with age 530-650 Ma.…”

Detrital zircon evidence for the reactivation of an Early Paleozoic syn-orogenic basin along the North Gondwana margin in South China

“…Wang et al, 2007;Li et al, 2010;Li et al, 2013). At the time of orogenesis, South China lie along the northern margin of Gondwana within an overall accretionary orogen that faced the proto-Tethys ocean (Cawood et al, 2007;Wang et al, 2010;Xu et al, 2012;Cawood et al, 2013;Wang et al, 2013;Xu et al, 2013). The Kwangsian orogeny is the local name given to a widespread orogenic pulse that extended along the North Gondwana margin from Turkey to Southeast Asia (Cawood et al, 2007).…”

Detrital zircon U–Pb geochronology, Lu–Hf isotopes and REE geochemistry constrains on the provenance and tectonic setting of Indochina Block in the Paleozoic

“…Torsvik and Cocks (2009) and Cawood et al (2013), however, plotted the Indochina Block as a discrete block in the paleo-Pacific, far away from the north margin of East Gondwana. In practice, the block was generally omitted in many paleogeographic reconstructions of the Gondwanaland (Li et al, 1995;Cawood and Buchan, 2007;Zhu et al, 2011;Xu et al, 2013). The uncertain paleogeography of the Indochina Block in Gondwana is due to the paucity of good quality of Paleozoic paleomagnetic and reliable geochronological and isotopic data, which has strictly hindered understanding of the position of the block.…”