Precambrian Research 224 (2013) 529–550 Contents lists available at SciVerse ScienceDirect Precambrian Research journa l h omepa g e: www.elsevier.com/locate/precamres Proliferation of MISS-forming microbial mats after the late Neoproterozoic glaciations: Evidence from the Kimberley region, NW Australia Zhong-Wu Lan a,c,∗ , Zhong-Qiang Chen b a State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China b State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Wuhan), Wuhan 430074, China c Key Lab of Petroleum Resources Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China a r t i c l e i n f o Article history: Received 9 July 2012 Received in revised form 12 October 2012 Accepted 4 November 2012 Available online 15 November 2012 Keywords: MISS (microbially induced sedimentary structures) Neoproterozoic glaciations The Kimberley Northwestern Australia a b s t r a c t A total of 20 morphological types of microbially induced sedimentary structures (MISS) are recognized from the late Neoproterozoic tillite-bearing successions of the Kimberley, northwestern Australia which include alpha-petees, triradiate cracks, multidirectional linear ridges, millimeter ripples, erosional rem- nants and pockets and so on. Of these, triradiate cracks, multidirectional linear ridges, and millimeter ripples are reported for the first time from the Neoproterozoic worldwide. Most Kimberley MISS are morphologically comparable with their ancient and present-day counterparts whose biogenicity have been well demonstrated. In the Kimberley, during the interglacial period MISS have colonization preference to relatively coarse sandy substrates (Ranford Formation) and their abundance decreased towards the younger strata (Throssell Shale). In contrast, MISS abundance increased from the older strata (Yurabi Formation) towards the younger strata (Flat Rock Formation) during the postglacial period. However, overall, both MISS abun- dance and bedding plane coverage percentage increased from the Marinoan-younger Marinoan/Gaskiers interglacial successions to younger Marinoan/Gaskiers postglacial successions, indicating a proliferation of microbial mats after the younger Marinoan/Gaskiers glaciation. The increase of microbial mats could have ameliorated marine biogeochemical conditions and ecosystems, and thus laid the foundation for the rise of Ediacaran biota in Australian basins. © 2012 Elsevier B.V. All rights reserved. 1. Introduction The earth underwent repeated glaciations between 750 and 580 millions years ago (Fairchild and Kennedy, 2007; Hoffman and Li, 2009), the younger two of which are Marinoan and Gaskiers glacia- tions. Neoproterozoic glaciations were believed to have changed the chemical and oxygenic conditions in oceans, and thus have set an agenda for the rise of the well-known Ediacaran biota (Knoll et al., 2004; Kaufman et al., 2007; Shen et al., 2008). However, the exact driving forces for the emergence of the Ediacaran biota have long been disputed (McCall, 2006), although the late Neoprotero- zoic ocean oxygenation (Grey and Calver, 2007a; Fike et al., 2007; McFadden et al., 2008) or asteroid impact (e.g. Acraman impact, Grey et al., 2003; Gostin et al., 2010) are believed to have facilitated the diversification of the Ediacaran biota. ∗ Corresponding author at: State Key Laboratory of Lithospheric Evolution, Insti- tute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China. Tel.: +86 10 82998445; fax: +86 10 62010846. E-mail address: lzw1981@126.com (Z.-W. Lan). Within marine ecosystems microbes were responsible for pro- ducing energy and nutrition for other animals, and mediating geochemical conditions in oceans (Ehrlich, 1998; Madigan et al., 2009). Their abundance and ecologic activities directly affected the primary productivity of marine ecosystems and compositions of consuming communities (Berglund et al., 2007; ˇ Soli ´ c et al., 2010). From this perspective, geomicrobiological study of microbial com- munities during and after glaciations is crucial for understanding the evolution of the Ediacaran ecosystem and the possible link between marine ecosystem changes and rise of Ediacaran biota. As one of the most important fossil records of microbes in Pre- cambrian successions, microbially induced sedimentary structures (MISS) are common in Proterozoic siliciclastic successions (Noffke et al., 2002; Schieber, 2007), and thus would provide necessary information relevant with shallow marine microbial communities. In Australia, the Ediacaran MISS and biota have been docu- mented from the late Neoproterozoic successions not only in central and South Australia (Bland, 1984; Logan et al., 1999; McCall, 2006; Willman et al., 2006; Maloof et al., 2010), but also in the Kimberley region, northwestern Australia (Lan and Chen, 2012a,b). In the Kimberley, the Neoproterozoic succession is up to 5300 m thick and dominated by the shallow marine siliciclastic 0301-9268/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.precamres.2012.11.008