Metazoan–microbial framework fabrics in a Mississippian (Carboniferous) coral–sponge–microbial reef, Monto, Queensland, Australia Jian-Wei Shen a,b, * , Gregory E. Webb c a South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, PR China b Key Laboratory of Marginal Sea Geology, South China Sea Institute of Oceanology and Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510301, PR China c School of Natural Resource Sciences, Queensland University of Technology, Brisbane, Qld 4001, Australia Received 7 August 2004; received in revised form 11 February 2005; accepted 30 March 2005 Abstract Microbial fabrics (stromatolites, thrombolites and calcimicrobes) occur in many Paleozoic carbonate buildups and commonly dominated reefs after mass extinction events (e.g., Middle Cambrian, Famennian [Late Devonian] and early Mississippian). By Vise ´an (middle Mississippian) time, eastern Australian reefs were mostly small, microbialite-dominated structures, but they contained diverse reef-building metazoans (e.g., rugose and tabulate corals, bryozoans) that came to dominate limited reef facies in some cases. Reefs in the Cannindah Limestone at Old Cannindah Homestead, Monto region, Queensland are exceptional in being the largest such reefs and in having the most complex and differentiated reef facies. They occurred on an oolitic–crinoidal bank characterized by long-term continuous carbonate deposition in a shallow, high- energy setting. Cannindah reef framework contained lithistid sponges and diverse corals, but was dominated by microbialite. The microbialites contain diverse thrombolites, microdigitate stromatolites, and calcimicrobes. Abundant syndepositional cavities in the microbial framework supported a diverse cryptic fauna including numerous calcimicrobes (e.g., Renalcis , Palaeomicrocodium, Girvanella , Ortonella , Aphralysia , and problematica), crinoids, and ostracodes. Cavities indicate that the framework was suprastratal both where microbialite-dominated and where skeletal organisms played a role in framework construction. Although these reefs grew following Late Devonian extinction events that affected skeletal reef builders, the dominance of microbialites is difficult to attribute to the absence of appropriate skeletal reef builders. The reefs occurred ~20 million years after the Devonian–Mississippian transition, and diverse, potentially reef-building corals and algae occur throughout the reefs, but never rose to dominate framework construction. High siliciclastic flux, turbidity, abnormal salinity, low oxygen levels, low light penetration, and climatic deterioration can be eliminated as limiting factors for skeletal organisms in the 0037-0738/$ - see front matter D 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.sedgeo.2005.03.011 * Corresponding author. South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, PR China. Fax: +86 20 84458964. E-mail address: jwshen@scsio.ac.cn (J.-W. Shen). Sedimentary Geology 178 (2005) 113 – 133 www.elsevier.com/locate/sedgeo