Early Triassic stromatolites in a siliciclastic nearshore setting in northern Perth Basin, Western Australia: Geobiologic features and implications for post-extinction microbial proliferation Zhong-Qiang Chen a, ⁎, Yongbiao Wang a , Stephen Kershaw b , Mao Luo c , Hao Yang a , Laishi Zhao d , Yuheng Feng a , Jianbo Chen d , Li Yang d , Lei Zhang d a State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Wuhan), Wuhan 430074, China b Institute for the Environment, Brunel University, Uxbridge, Middlesex, UK c School of Earth and Environment, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia d State Key Laboratory of Geological Process and Mineral Resources, China University of Geosciences (Wuhan), Wuhan 430074, China abstract article info Article history: Received 7 November 2013 Received in revised form 2 July 2014 Accepted 7 July 2014 Available online 12 July 2014 Keywords: Stromatolite Early Triassic Fossilized cyanobacteria Perth Basin Gondwana An Early Triassic stromatolite deposit in Gondwana is documented from the Smithian succession of the Lower Triassic Kockatea Shale Formation in the Northampton area, northern Geraldton, Western Australia. Abundant tube-like sheaths of filaments and tiny circular microspherule balls are well preserved in laminae of the North- ampton stromatolites, which are characterized by finely laminated domes and digitate high-relief columns. These filament sheaths are superficially analogous to their counterparts of modern stromatolites, and thus are interpreted as putative fossilized filamentous cyanobacteria. Elemental mapping of EDS analysis shows very high contents of both Fe and Si elements as well as common presence of both S and Al elements along the laminae of the stromatolites, suggesting that the stromatolites may have been ferritized or silicified. Both ferritization and silicification may have played a crucial role in the exceptional preservation of the micro-structures in the North- ampton stromatolites. The high content of Al along the laminae indicates that the stromatolites may have been influenced by terrigenous fine-grained clastics during their growth. The Northampton stromatolites show several growth modes, initiating on either pebbles/conglomerates or sandy seafloor and building laminar domes and dig- itate, high-relief columns during an initial transgression period. Steady increase in sea level facilitated the growth of stromatolites. The Early Triassic stromatolites ceased growth due to either rapid rise in sea level or increased clay influx probably sourced from increased weathering on land at that time, or both. The occurrence of the Northampton stromatolites in the siliciclastic succession, in comparison with published records of Early Triassic microbialites, reveals that post-extinction microbialites were widespread in the Smithian. Stromatolites show a broad geographic distribution from low-latitude to southern high-latitude regions of Gondwana and inhabited not only carbonate settings, but also siliciclastic nearshore settings. All features of these Early Triassic stromato- lites indicate a microbial bloom in the aftermath of the P–Tr mass extinction. © 2014 Elsevier B.V. All rights reserved. 1. Introduction As consequence of the severe biocrisis at the end of the Permian Period, marine ecosystems underwent the most devastating global deg- radation of Phanerozoic history (Erwin, 2006). Microbe-dominated eco- systems were the most widely spread during the Early Triassic than during any other periods of the Phanerozoic (Chen and Benton, 2012). Microbialites deposited after the end-Permian event have been general- ly considered as ecologically and biogenically special sediments, characteristic of stressful environments in the aftermath of the most devastated ecologic crisis of Earth history (Schubert and Bottjer, 1992; Garzanti et al., 1998; Kershaw et al., 1999; Lehrmann, 1999; Paul and Peryt, 2000; Kershaw et al., 2002; Wignall and Twitchett, 2002; Ezaki et al., 2003; Baud et al., 2005; Wang et al., 2005; Hips and Haas, 2006; Baud et al., 2007; Farabegoli et al., 2007; Kershaw et al., 2007; Sano and Nakashima, 2007; Ezaki et al., 2008; Mary and Woods, 2008; Yang et al., 2008; Kershaw et al., 2011; Mata and Bottjer, 2011; Yang et al., 2011; Ezaki et al., 2012; Kershaw et al., 2012; Mata and Bottjer, 2012). Of these, most Lower Triassic microbialites are thrombolites, while stro- matolites are less common (Mata and Bottjer, 2012). The resurgence of microbial communities occurred through the entire Early Triassic recov- ery interval, with four episodes of high abundance of microbialites in Global and Planetary Change 121 (2014) 89–100 ⁎ Corresponding author. E-mail address: zhong.qiang.chen@cug.edu.cn (Z.-Q. Chen). http://dx.doi.org/10.1016/j.gloplacha.2014.07.004 0921-8181/© 2014 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Global and Planetary Change journal homepage: www.elsevier.com/locate/gloplacha