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Sedimentological, paleontological, and geochemical data from core XK-1 on the Xisha Islands have allowed for a detailed documentation of the early carbonate development around the Oligocene-Miocene transition in the northern South China Sea (SCS). The deposits within the fore reef, reef, lagoon environments occurred before 23 Ma, the exposure horizon occurred around 23 Ma, and the sediments within the open lagoon setting dominated after 23 Ma. This evolution indicates a sedimentological response to water depth change, which is the combined result of eustatic sea-level fluctuations and tectonic subsidence. The tectonic subsidence during the latest Oligocene and Early Miocene (especially this period) was responsible for the obvious deepening trend. What's more, substantial physical erosion caused an increased amount of terrigenous input into the Xisha Islands area, with detrimental effects on carbonate development after the Oligocene-Miocene boundary. Over the entire South China Sea, the early carbonate systems along the northern and southern margins displayed specific evolution patterns. After comparing these patterns, we found a close relationship between the carbonate initiation and the subduction of the proto-SCS and the opening of the modern SCS. Therefore, it has been demonstrated that sea level and local tectonics as well as paleoclimatic conditions were the main controlling factors in shaping the onset of carbonate sedimentation in the SCS.

Miocene carbonates of the Eratosthenes Seamount, located offshore from Cyprus in the Eastern Mediterranean (ODP Leg 160, Site 966), have been re-analysed. The use of SEDEX sequential extraction to evaluate the nutrient concentrations and of CT-Scan for the identification of large benthic foraminifera has resulted in a more detailed palaeoenvironmental reconstruction and an improved stratigraphic framework. Three intervals are recognised in the succession and are attributed to the lower, middle and upper Miocene, respectively. The lower Miocene interval is dominated by large benthic foraminifera and echinoids. This association colonized the top of the seamount following its uplift from deep-water to the photic zone. The middle Miocene interval is characterised by rhodoliths and corals at its base and near the top, whereas seagrass/seaweed assemblages (with epiphytic foraminifera and hooked coralline-algal crusts) dominate its central part. The upper Miocene is represented by coral reef facies near its base and lagoonal facies toward its top. The succession was deposited in an oligotrophic environment and exhibits a general shallowing-upward trend that was mainly controlled by tectonic activity related to the northward subduction of the African plate. The succession of the Eratosthenes Seamount is characterised by a diverse large benthic foraminifera assemblage in its lower part and by corals in its uppermost part, whereas corallines characterise the central interval. This trend is common in Miocene Mediterranean carbonates and its occurrence on an isolated seamount confirms its connection with the general evolution of the basin. The decline of miogypsinids and lepidocyclinids after the early Miocene is notable because the Eratosthenes Seamount was geographically close to the Indo-Pacific Ocean where both groups also thrived during the middle Miocene. This decline was probably caused by the early Miocene closure of the deep-water connection between the Indo-Pacific and the Mediterranean.

Large benthic foraminifera are important components of tropical shallow water carbonates. Their structure, developed to host algal symbionts, can be extremely elaborate and presents stratigraphically-significant evolutionary patterns. Therefore their distribution is important in biostratigraphy, especially in the Indo-Pacific area. To provide a reliable age model for two intervals of IODP Hole U1468A from the Maldives Inner-Sea, large benthic foraminifera have been studied with computed tomography. This technique provided 3D models ideal for biometric-based identifications, allowing the upper interval to be placed in the late middle-Miocene and the lower interval in the late Oligocene.