TY - CONF T1 - Coralline algae from the Miocene Mahakam Delta (East Kalimantan, SE Asia) T2 - GSA Annual Meeting 2012 Y1 - 2012 A1 - Anja Rösler A1 - Juan Carlos Braga AB - Although the Miocene is the epoch of the onset of the biodiversity hotspot in South East Asia, crustose coralline algae (CCA) of this age are poorly known in region. To fill this knowledge gap, crucial to understand the evolutionary history of reef building coralline algae, we studied CCA in Miocene reefs in the Kutai Basin, the largest sedimentary basin in Borneo that was dominated by siliciclastic sediments of the Proto-Mahakam delta. Local carbonate buildups comprising low relief patch reefs occur within the deltaic succession in shallow and turbid water, influenced by high siliciclastic input (Wilson, 2002). CCA in the Kutai basin are mostly found in association with coral reefs, encrusting corals or fragments of them. In beds with very high siliciclastic content no coralline algae were observed in the outcrops, but corals were still present. Two main CCA assemblages have been recognized in the studied Middle Miocene reefs: 1) a shallow-water assemblage, with two species of Neogoniolithon, thick crusts of Spongites, various Hydrolithon and also Sporolithon and Lithoporella. 2) In darker waters preferentilaly grew melobesioid assemblages, dominated by rhodoliths mainly consisting of Lithothamnion or by thin crusts of Mesophyllum and Sporolithon. This last one is the only assemblage found in mesophotic reefs. CCA of East Kalimantan show occurrences of some extant species earlier than expected. These new first-occurrence dates are being used to produce a detailed time tree of the main reef building CCA species with the help of a new molecular phylogeny based on five genetic markers. Wilson Moyra E.J. (2002) Cenozoic carbonates in Southeast Asia: implications for equatorial carbonate development. Sedimentary Geology 147, 295– 428 JF - GSA Annual Meeting 2012 CY - Charlotte, USA ER - TY - CONF T1 - Palaeoenvironmental reconstruction of a Miocene patch reef in East Kalimantan (Indonesia): a close-up on the bryozoan component T2 - IBA Larwood Meeting Y1 - 2012 A1 - Emanuela Di Martino A1 - Paul D. Taylor A1 - Vibor Novak A1 - Nadiezhda Santodomingo A1 - Anja Rösler A1 - Juan Carlos Braga A1 - Kenneth G. Johnson A1 - Willem Renema JF - IBA Larwood Meeting CY - Brno Czech Republic ER - TY - CONF T1 - Bryozoans from a Langhian patch reef in East Kalimantan (Indonesia) T2 - Giornate di Paleontologia XII edizione – Catania, 24-26 Maggio 2012 Y1 - 2012 A1 - Emanuela Di Martino A1 - Paul D. Taylor A1 - Vibor Novak A1 - Nadiezhda Santodomingo A1 - Anja Rösler A1 - Juan Carlos Braga A1 - Kenneth G. Johnson A1 - Willem Renema JF - Giornate di Paleontologia XII edizione – Catania, 24-26 Maggio 2012 CY - Catania, Italy ER - TY - CONF T1 - The origins and evolution of the modern Indo-Pacific reef algal flora: the coralline algae in the context of the THROUGHFLOW Project T2 - 10th International Symposium on Fossil Algae Y1 - 2011 A1 - Anja Rösler A1 - Juan Carlos Braga A1 - Francisco Perfectti KW - carbonates KW - coralline algae KW - INDO-PACIFIC KW - paleoenvironmental reconstruction KW - REEF KW - THROUGHFLOW project AB - South East (SE) Asia hosts the global centre of maximum diversity for shallow marine ecosystems, mainly associated with thriving coral reefs (Renema et al., 2008). The factors responsible for the origins and maintenance of this diverse biota remain unknown. Previous studies suggest that the formation of the ancestral centre of diversity could be related to the constriction of the Indonesian Throughflow current (ITF) during the Cenozoic, resulting in increased speciation and/or immigration during the Miocene. Unfortunately, the fossil evidence currently available to document this pattern and its geographic context is sparse, and there is a need to collect new data. The scientific objective of the THROUGHFLOW Project is to reconstruct the biological and environmental history of shallow marine habitats of a selected area of Southeast Asia. Specifically, a multidisciplinary study of key sections in Eastern Kalimantan (Indonesia) will be performed, integrating data from geology, geochemistry, ocean modeling, and paleontology to understand the Neogene history of the region. In this framework, the projects carried out at Granada University aim to document the timing and patterns of the diversification of Indo-Pacific reef-building coralline algae, the second most important builders in modern Indo-Pacific reefs. The collected data will be integrated with a robust sedimentological framework for detailed reconstructions of the shallow marine carbonate paleoenvironments and their evolution through time. The first expedition has been already carried out in East Kalimantan (Indonesia) during November-December 2010. A variety of shallow marine ecosystems, including coral reefs and sea grass environments, were found. First results show an exceptional preservation of some fossil algae, especially in places with a high siliciclastic influence (Miocene deposits of the Mahakam Delta). A new expedition is scheduled for summer 2011. We will study a wider temporal (Early to Late Miocene and possibly Late Oligocene) and spatial range of outcrops. Acknowledgements: This paper is a contribution to the project supported by Marie Curie Actions, Seventh Framework Programme (Grant No. 237922). JF - 10th International Symposium on Fossil Algae PB - International Fossil Algae Association CY - Cluj Napoca, Romania ER -