ORIGINAL PAPER Mississippian (Early Carboniferous) stromatolite mounds in a fore-reef slope setting, Laibin, Guangxi, South China Jian-Wei Shen Æ Hairuo Qing Received: 30 August 2007 / Accepted: 2 November 2008 / Published online: 28 November 2008 Ó Springer-Verlag 2008 Abstract The Mississippian (Early Carboniferous) is generally a period of scarce carbonate buildups in South China. This study documents outcrops of stromatolite mounds at Mengcun and Helv villages, in Laibin City, Guangxi Province, South China. The stromatolite mounds contain various stromatolite morphologies including lami- nar, wavy-laminar, domal or hemispheroidal, bulbous, and flabellate-growth columns. Intramound rocks are brachio- pod floatstone and dark thin-bedded laminated micrite limestone. Individual stromatolites at Mengcun village are generally 3–6 cm thick and morphologically represent relatively shallow-water laminar (planar and wavy-undu- lated stromatolites) and deeper-water domal, bulbous and columnar forms. Where mounds were formed, the stro- matolites continued growing upward up to 60 cm thick. Thrombolitic fabrics also occur but are not common. Stromatolite microscopic structure shows the bulk of the lamination to consist of wavy microbialite and discrete thin micritic laminae. These mounds are intercalated in deep-water fore-reef talus breccia, packstone formed as a bioclastic debris flow and thin-bedded limestone containing common chert layers of the Tatang Formation (late Vise ´an). Further evidence supporting the deep-water setting of the stromatolite mounds are: (1) a laterally thinning horizon of brachiopod floatstone containing deep- water, small, thin-shelled brachiopods, peloidal micritic sediments and low-diversity, mixed fauna (e.g., thin-shel- led brachiopods, tube-like worms and algae) that have been interpreted as storm deposits, (2) common fore-reef talus breccias, (3) lack of sedimentary structures indicating current action, (4) preservation of lamination with sponge spicules, and (5) lack of bioturbation suggesting that the stromatolites grew in a relatively low energy, deep-water setting. The stromatolite mounds are the first described stromatolite mounds in Mississippian strata of South China and contain evidence that supports interpretations of (1) growth history of Mississippian microbial buildups and (2) environmental controls on stromatolite growth and lithification. Keywords Stromatolite Á Mounds Á Fore-reef slope setting Á Mississippian Á South China Introduction Mississippian (Early Carboniferous) carbonate buildups have been the subject of much attention (e.g., Lane and Ormiston 1982; James 1983; West 1988; Bridges et al. 1995; Webb 2002) because of their palaeoclimatic impor- tance and to the insights they provide into the recovery processes of skeletal reef builders associated with the Frasnian-Famennian and end-Devonian extinction events (Newell 1972; Fisher 1981; James 1983; Sheehan 1985; West 1988; Frakes et al. 1992; Bridges et al. 1995; Caplan and Bustin 1999; Saltzman et al. 2000; Aretz and Chevalier J.-W. Shen (&) Department of Marine Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 510301 Guangzhou, People’s Republic of China e-mail: jwshen@scsio.ac.cn J.-W. Shen Key Laboratory of Marginal Sea Geology, South China Sea Institute of Oceanology and Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 510301 Guangzhou, People’s Republic of China H. Qing Department of Geology, University of Regina, Regina, SK S4S 0A2, Canada 123 Int J Earth Sci (Geol Rundsch) (2010) 99:443–458 DOI 10.1007/s00531-008-0392-2