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The tectonic and paleoceanographic setting of the Great Australian Bight (GAB) and the Mentelle Basin (MB; adjacent to Naturaliste Plateau) offered an outstanding opportunity to investigate Cretaceous and Cenozoic climate change and ocean dynamics during the last phase of breakup among remnant Gondwana continents. Sediment recovered from sites in both regions during International Ocean Discovery Program Expedition 369 will provide a new perspective on Earth's temperature variation at sub-polar latitudes (60°-62°S) across the extremes of the mid-Cretaceous hot greenhouse climate and the cooling that followed. The primar y goals of the expedition were to • Investigate the timing and causes for the rise and collapse of the Cretaceous hot greenhouse climate and how this climate mode affected the climate-ocean system and oceanic biota; • Determine the relative roles of productivity, ocean temperature, and ocean circulation at high southern latitudes during Cretaceous oceanic anoxic events (OAEs); • Identify the main source regions for deep-water and intermediate-water masses in the southeast Indian Ocean and how these changed during Gondwana breakup; • Characterize how oceanographic conditions at the MB changed during the Cenozoic opening of the Tasman Passage and restriction of the Indonesian Gateway; • Resolve questions on the volcanic and sedimentary origins of the Australo-Antarctic Gulf and Mentelle Basin and provide stratigraphic control on the age and nature of the prebreakup successions. Hole U1512A in the GAB recovered a 691 m thick sequence of black claystone ranging from the early Turonian to the early Campanian. Age control is primarily based on calcareous nannofossils, but the presence of other microfossil groups provided consistent but low-resolution control. Despite the lithologic uniformity, longand short-term variations in natural gamma ray and magnetic susceptibility intensities show cyclic alternations that suggest an orbital control of sediment deposition that will be useful for developing an astrochronology for the sequence. Sites U1513-U1516 were drilled between 850 and 3900 m water depth in the MB and penetrated 774, 517, 517, and 542 meters below seafloor (mbsf), respectively. Under a thin layer of Pleistocene-upper Miocene sediment, Site U1513 cored a succession of Cretaceous units from the Campanian to the Valanginian. Site U1514 sampled an expanded Pleistocene-Eocene sequence and terminated in the upper Albian. The Cenomanian-Turonian interval at Site U1514 recovered deformed sedimentary rocks that probably represent a detachment zone. Site U1515 is located on the west Australian margin at 850 m water depth and was the most challenging site to core because much of the upper 350 m was either chert or poorly consolidated sand. However, the prebreakup Jurassic(?) sediments interpreted from the seismic profiles were successfully recovered. Site U1516 cored an expanded Pleistocene, Neogene, and Paleogene section and recovered a complete Cenomanian/Turonian boundary interval containing five layers with high total organic carbon content. Recovery of well-preserved calcareous microfossil assemblages from different paleodepths will enable generation of paleotemperature and biotic records that span the rise and collapse of the Cretaceous hot greenhouse (including OAEs 1d and 2), providing insight to resultant changes in deep-water and surface water circulation that can be used to test predictions from earth system models. Paleotemperature proxies and other data will reveal the timing, magnitude, and duration of peak hothouse temperatures and any cold snaps that could have allowed growth of a polar ice sheet. The sites will also record the mid-Eocene-early Oligocene opening of the Tasman Gateway and the Miocene-Pliocene restriction of the Indonesian Gateway; both passages have important effects on global oceanography and climate. Understanding the paleoceanographic changes in a regional context provides a global test on models of Cenomanian-Turonian oceanographic and climatic evolution related both to extreme Turonian warmth and the evolution of OAE 2. The Early Cretaceous volcanic rocks and underlying Jurassic(?) sediments cored in different parts of the MB provide information on the timing of different stages of the Gondwana breakup. The recovered cores provide sufficient new age constraints to underpin a reevaluation of the basin-wide seismic stratigraphy and tectonic models for the region.

The dissolved Yttrium (Y) and Rare Earth Element (REE) concentrations of seawater samples collected along a north-south hydrological transect within the Bay of Bengal (BoB) have been analyzed to estimate contributions of the Ganges and Brahmaputra (G-B) river inputs to the dissolved REE distribution of the Northern Indian Ocean. Surface water masses of the BoB are characterized by Y/Ho ratios (84) intermediate between the G-B river suspended sediment (41) and water mass from the South Indian Ocean (93). Co-variation of MREE (Middle REE, Sm) and LREE (Light REE, La) concentrations suggests that the dissolved REEs in surface waters (upper 100 m depth) of the BoB (Sm/La = 0.21) appear to derive mainly from the freshwater discharge of the G-B river system. In contrast, values obtained in the intermediate and deep-waters (Sm/La = 0.14) suggest a mixing of dissolved REEs deriving from the release of G-B river suspended particles (Sm/La = 0.16) and the contribution of Antarctic Bottom Water (AABW) (Sm/La = 0.12). Consequently, we propose that MREE/MREE* ratios in the BoB waters could be an accurate proxy to trace lithogenic inputs from the G-B river system. The dissolved and particle re-mineralization Nd fluxes from G-B river system are calculated to constitute about 9% and 4% of the global dissolved river discharge and ‘Boundary inputs' flux. Our estimation indicates that the massive G-B river system inputs could greatly alter the dissolved REEs distribution in the BoB and contribute to the dissolved REEs budget in the ocean

The radiogenic strontium (Sr) and neodymium (Nd) isotope compositions of the detrital fraction of surface and subsurface sediments have been determined to trace sediment provenance and contributions from Asian dust off the east coast of Luzon Islands in the western Philippine Sea. The Sr and Nd isotope compositions have been very homogenous near the east coast of the Luzon Islands during the latest Quaternary yielding relatively least radiogenic Sr (Sr-87/Sr-86 = 0.70453 to 0.70491) and more radiogenic Nd isotope compositions (epsilon(Nd)(0) = +5.3 to +5.5). These isotope compositions are similar to Luzon rocks and show that these sediments were mainly derived from the Luzon Islands. In contrast, the Sr and Nd isotope compositions of sediments on the Benham Rise and in the Philippine Basin are markedly different in that they are characterized by overall more variable and more radiogenic Sr isotope compositions (Sr-87/Sr-86 = 0.70452 to 0.70723) and less radiogenic Nd isotope compositions (epsilon(Nd)(0) = -5.3 to +2.4). The Sr isotope composition in the Huatung Basin is intermediate between those of the east coast of Luzon and Benham Rise, but shows the least radiogenic Nd isotope compositions. The data are consistent with a two end-member mixing relationship between Luzon volcanic rocks and eolian dust from the Asian continent, which is characterized by highly radiogenic Sr and unradiogenic Nd isotope compositions. The results show that Asian continental dust contributes about 10-50% of the detrital fraction of the sediments on Benham Rise in the western Philippine Sea, which offers the potentials to reconstruct the climatic evolution of eastern Asia from these sediments and compare this information to the records from the central and northern Pacific. Key Points Sr and Nd isotopic signatures of lithogenic fraction from the Philippine Sea Asian dust input in the western Philippine Sea Offer potentials for reconstructions of the climatic evolution of Asia