02693nas a2200157 4500008004000000245009300040210006900133260002000202520217200222100002402394700002002418700001702438700001802455700001902473856004302492 0 engd00aMicrobial carbonates in Miocene reefs in the Mahakam Delta in East Kalimantan, Indonesia0 aMicrobial carbonates in Miocene reefs in the Mahakam Delta in Ea aBerlin, Germany3 a

Coral patch reefs in the Miocene Mahakam Delta in East Kalimantan (Borneo, Indonesia) grew in shallow marine turbid waters. These patch reefs developed from delta front to deeper (prodelta) settings in areas with temporary reduced siliciclastic input. Langhian reef deposits are well exposed in limestone quarries in the Samarinda area and locally include microbial carbonates. Two different types of microbial carbonates have been found around Samarinda in two localities 2 km apart. These sections were logged in detail and 208 samples were collected. Meso and macrostructure of microbialites were identified at the outcrops. Thin sections from carbonate samples were examined under optical microscope and microfacies were classified using the Dunham (1962) and Insalaco (1998) terms. The carbonate content was analyzed using Total Inorganic Carbon analysis, with 12% carbon as a standard for carbon calibration. In the northern section, microbialites occur as low-relief domes, up to 2 m wide and 0.5 m high, with internal lamination, developed around large coral fragments at the transition from reef deposits to fine-grained siliciclastics.
The second type of microbialites has been found in the southern locality as decimeter-scale nodules ("megaoncoids") formed around nuclei of large coral fragments. Small nodules were bound together into bigger nodules. Microbial micrite with laminated to digitated fabrics intergrew with coralline algae to form the thick covers of these "megaoncoids", which laterally change into coral boundstones. In both sections microbialites are not components of the reef framework. They grew around large coral fragments on the flanks of the patch reefs. The microbialites that form low relief domes developed on nearly flat, stable seafloor seawards of the patch reef. The "megaoncoids" in the southern section formed as a result of downslope movement of coral fragments coated by microbialite/coralline algal crust. The steep slope at the flank of the patch reef favored falling and overturning of encrusted corals and continued growth of microbial crusts on other sides of nodules.

1 aPretković, Vedrana1 aBraga, Juan, C.1 aNovak, Vibor1 aRösler, Anja1 aRenema, Willem uhttps://ipaeg.myspecies.info/node/207003199nas a2200157 4500008004100000245010100041210006900142260003200211520265700243100002402900700002002924700001702944700001802961700001902979856004302998 2013 eng d00aMicrobial carbonates in Miocene reefs in the Mahakam Delta in East Kalimantan, Borneo, Indonesia0 aMicrobial carbonates in Miocene reefs in the Mahakam Delta in Ea aBerlin, Germanyc11/03/20133 a

Microbial carbonates are deposits that form by the activity of bentic microbial communities. Microbialites usually form domical, columnar or conical structures and can have laminated, clotted, dendritic or homogenous macrofabric. They have a broad distribution and can grow in a variety of different environments such as hot springs, freshwater lakes, hypersaline lakes, reefs and other marine environments. This research focuses on microbialites associated to coral reefs. Coral patch reefs in the Miocene Mahakam Delta in East Kalimantan (Borneo, Indonesia) grew in shallow marine turbid waters. These patch reefs developed from delta front to deeper (prodelta) settings in areas with temporary reduced siliciclastic input. Langhian reef deposits are well exposed in limestone quarries in the Samarinda area and locally include microbial carbonates. Two different types of microbial carbonates have been found around Samarinda in two localities 2 km apart. These sections were logged in detail and 208 samples were collected. Meso and macrostructure of microbialites were identified at the outcrops. Thin sections from carbonate samples were examined under optical microscope and microfacies were classified using the Dunham (1962) and Embry and Klovan (1971) terms. The carbonate content was analyzed using Total Inorganic Carbon analysis, with 12% carbon as a standard for carbon calibration. In the northern section, microbialites occur as low-relief domes, up to 2 m wide and 0.5 m high, with internal lamination, developed around large coral fragments at the transition from reef deposits to fine-grained siliciclastics.
The second type of microbialites has been found in the southern locality as decimeter-scale nodules ("megaoncoids") formed around nuclei of large coral fragments. Small nodules were bound together into bigger nodules. Microbial micrite with laminated to digitated fabrics intergrew with coralline algae to form the thick covers of these "megaoncoids", which laterally change into coral boundstones. In both sections microbialites are not components of the reef framework. They grew around large coral fragments on the flanks of the patch reefs. The microbialites that form low relief domes developed on a nearly flat, stable seafloor seawards of the patch reef. The "megaoncoids" in the southern section formed as a result of downslope movement of coral fragments coated by microbialite/coralline algal crust. The steep slope at the flank of the patch reef favoured falling and overturning of encrusted corals and continued growth of microbial crusts on other sides of nodules.

1 aPretković, Vedrana1 aBraga, Juan, C.1 aNovak, Vibor1 aRösler, Anja1 aRenema, Willem uhttps://ipaeg.myspecies.info/node/206902123nas a2200145 4500008004500000245007800045210006900123520164400192100001801836700002401854700001701878700001901895700002001914856004301934 In Press eng d 00aCoralline Algae from the Miocene Mahakam Delta (East Kalimantan, SE Asia)0 aCoralline Algae from the Miocene Mahakam Delta East Kalimantan S3 a

Miocene crustose coralline algae (CCA) from the South East Asia are poorly known, although the Miocene is the epoch of the onset of the biodiversity hotspot in the region and CCA are crucial to understand the evolutionary history of reef building. To fill this knowledge gap, CCA from Lower and Middle Miocene reefs and related carbonates in the Kutai Basin in East Kalimantan (Borneo, Indonesia) have been studied. The Kutai Basin was dominated by siliciclastic sediments of the Proto-Mahakam delta and only locally carbonate buildups occur laterally to or within the deltaic succession. CCA in the Kutai Basin occur in low-energy shallow-water platform carbonates and in association with coral reefs, encrusting the corals or bioclasts. Two main CCA assemblages have been recognized: 1) A shallow-water assemblage (S-assemblage), dominated by Neogoniolithon spp., thick crusts of Spongites spp., and Hydrolithon spp.; and 2) the D-assemblage, mainly consisting of thin crusts of Lithothamnion spp., Mesophyllum spp., and Sporolithon spp., which grew in darker waters. Light reduction in reefs in the Proto-Mahakam delta was due to increased water depth or higher turbidity by higher siliciclastic input. Assemblages with intermediate composition (I-assemblages) can also be found. Common CCA with large cells fusions and groups of heterocysts, typical features of modern reef CCA, in the S-assemblages in the Middle Miocene of East Kalimantan reflect the initiation of the reef-building CCA flora in the Indo-Pacific region. The occurrence of this kind of CCA confirms the biogeographic differentiation of a tropical reef flora.

1 aRösler, Anja1 aPretković, Vedrana1 aNovak, Vibor1 aRenema, Willem1 aBraga, Juan, C. uhttps://ipaeg.myspecies.info/node/204000923nas a2200289 4500008004100000245008400041210006900125260003500194300000800229490000700237653001400244653002400258653001200282653003800294653001600332100002800348700001700376700002100393700002500414700002100439700002100460700002400481700001800505700001900523700002500542856006600567 2012 eng d00aDevelopment of a turbid reef in the Middle Miocene (East Kalimantan, Indonesia)0 aDevelopment of a turbid reef in the Middle Miocene East Kalimant aCharlotte, North Carolina, USA a6230 v7710aINDONESIA10amarginal ecosystems10aMiocene10apalaeonvironmental reconstruction10apatch reefs1 aSantodomingo, Nadiezhda1 aNovak, Vibor1 aMarshall, Nathan1 aDi Martino, Emanuela1 aFraser, Nicholas1 aLoGiudice, Elena1 aPretković, Vedrana1 aRösler, Anja1 aRenema, Willem1 aJohnson, Kenneth, G. uhttps://gsa.confex.com/gsa/2012AM/webprogram/Paper209284.html