At the IODP Forum 2017 in Shanghai, IODP-China proposed initiating the discussions on “IODP beyond 2023”, and the meeting supported China’s proposal to host and co-lead the activities for preparing the science plan of ocean drilling after 2023. The present paper started from an overview of the planning processes of ocean drilling science over the past decades, then analysed the scientific targets and perspectives of the future ocean drilling, and concluded with suggestions about how China should prepare the international discussions on “IODP beyond 2023”.Since half a century, the ocean drilling has played a role of locomotive in international Earth science community and of flagship in deep-sea research.China’s initiation and co-leadership in preparing its science plan for the next decade will promote the upgrading of Earth science in our country, yet the success of the endeavor heavily depends on active involvement of the scientific community , especially on its contribution with creative thinking.

The Antarctic and the Arctic regions play a key role in global sea level change and carbon cycle, and reserve key information of the Cenozoic transition from a green-house to an ice-house Earth. They have become hot spots in earth science studies. The geological drilling projects in both polar regions (e.g., DSDP/ODP/IODP/ICDP) have achieved remarkable successes, which have freshened the knowledge of global environmental and climatic evolution. Along with the Cenozoic global cooling, the timing of glaciation was almost synchronous on both the Antarctic and the Arctic. Accompanied with the Antarctic ice sheet build-up and increased terrestrial weathering, the enhanced formation of Antarctic Bottom Water exerts significant impact on global ocean circulation. The volume of unstable West Antarctic Ice Sheet fluctuates during glacial-interglacial periods showing 40 ka obliquity cycles, its volume significantly reduced or collapsed during several peak interglacials or long warm intervals. The Southern Ocean plays a significant role modulating atmospheric CO₂ concentration, global deep water circulation and nutrient distribution, productivity at different time scales. Sea level responses to the waxing and waning of polar ice sheets at different time intervals were tested, which provide valuable clue for predicting future sea level changes. The upcoming IODP drilling projects on polar regions will keep focusing on the high latitude ice sheet development, Southern Ocean paleoceanographic evolution, land-ocean linkages in the Arctic, and the impacts on the global climate, which will provide important boundary conditions for predicting global future climate evolution.

Knowledge of ocean crust is one of bases to understand the deep and the surface of our planet. Since the definition of the Earth crust based on the geophysical discovery of Moho, marvelous efforts have been made to understand the geological significance of the Moho and the structure of the ocean crust. Up to date, it becomes clear that the Penrose model built up on ophiolite is unsuitable for the explanation of the ocean crust structure along slow and ultraslow spreading ridges, and probably also questionable for that of fast spreading ridges. The only effective way to solve the problem is to drill into the geophysical detected Moho and get samples. With the development of modern technology and more logic scientific strategy, that largely improved from the milestone Mohole projects carried out about half a century ago. The time to realize the Mohole dream seams coming.

Subduction zones are one of the most critical types of plate boundary of the Earth system, crucial for the global geochemical recycling of the Earth system, genesis of island arc and continental crust, and mechanisms of earthquake and tsunami processes. Ocean drilling plays an essential role in advancing our understanding of the subduction processes. This paper highlights the recent progress and scientific goals of the international ocean drilling programs in subduction systems and discusses implications for strategic planning of the future ocean drilling initiatives.

Aiming at the current climate status, i.e., drastic rise of atmospheric greenhouse gases and the apparent trend of global warming, the International Ocean Discovery Program (IODP), launched in 2013, proposed four scientific challenges, including the response of global climate to CO₂ rise, the feedback of ice-sheet and sea-level to global warming, the dynamics of the mid- and low-latitude hydro-cycle, and the mechanism of the marine carbon-chemical buffering system. By August 2017, eight IODP expeditions of climate-related themes were implemented, focusing on the Neogene evolution of the monsoon system over Asia-Pacific-Indian and the West Pacific Warm Pool, with specific interests in the variabilities and mechanisms of the Asian Monsoon system on orbital-to millennial-scales, as well as the connections between Asian Monsoon and the uplift/weathering of the Tibetan Plateau on tectonic time scale. The planned IODP expeditions in the forthcoming two years will explore the Southern high-latitude climate histories of West Antarctic ice in the Cenozoic, and Southern Ocean currents and carbon cycle in the Cretaceous-Paleogene. In sum, during the current phase of IODP (2013-2023), our knowledge about the marine climate system would be greatly advanced via deciphering the past changes in tropical processes of Asian Monsoon and West Pacific Warm Pool, as well as in high-latitude factors of the West Antarctic ice. A better scientific background of natural variability would be provided, accordingly, for predicting the future tendency in climate change. In this context, China’s strategic directions include the global monsoon concept, the tropical forcing hypothesis, and in particular the climate effect of the Sunda Shelf.

In the past 50 years, we have witnessed remarkable progress in our understanding of the Earth and ocean system, as a result of the internationally integrated deep ocean drilling programs, the Deep Sea Drilling Program (DSDP), the Ocean Drilling Program (ODP), and the Integrated Ocean Drilling Program (IODP). One of the legacies of the deep ocean drilling programs is the development and applications of the CORK, Circulation Obviation Retrofit Kit. Earth and ocean sciences have been shifting from a traditional discontinuous, expeditionary mode toward a mode of sustained in situ observations today. The seafloor CORK observatories offer Earth, ocean and life scientists new opportunities to study multiple, interrelated deep marine subsurface processes, over time scales ranging from seconds to decades. Here, we first provided a concise examination of the development history of the CORKs, then described the first installations of ODP CORKs, the evolution of different models of CORK, and finally, summarized the scientific lessons learned in the installation and operation effort of the CORKs. In the end, we offered our perspectives on using CORKs to study geological, hydrogeological, microbiological, and biogeochemical processes in the deep marine subsurface biosphere, particularly pertaining to China’s efforts in establishing and enhancing its deep-sea and deep-biosphere research and monitoring programs.

The prerequisite for obtaining variations of terrigenous grain-size of marine sediments is how to effectively remove non-terrigenous matters and preserve terrigenous particles synchronously. Combined with observations under biological microscope and scanning electron microscope, a comparative study of biogenic debris removal effect and terrigenous grain-size analysis under different pretreatment condition was performed on core sediments, which were retrieved in the South China Sea during the MD190 cruise. Our new results showed that the main three biogenic particles, namely, organic matter, carbonate, and opal in marine sediments could be removed effectively by 30% H₂O₂ in a stirring water bath at 60 ℃ for 3 h, 0.5% HCl for 1 h, and 2 mol/L Na₂CO₃ in a stirring water bath at 85 ℃ for 5 h, in turn. Such pretreatments achieved the goals of biogenic debris removal efficiency and relatively well-preserved terrigenous particles. Prior to selecting an appropriate pretreatment method, this study suggested that the actual effects of biogenic detritus on grain-size results of diverse marine sediment samples should be taken into account. If the laboratory data are ensured to be closer to the natural grain-size distribution of terrigenous particles, the removals of all biogenic debris are not always needed, and the less pretreatment processes the better. For example, opal particles have little effect on terrigenous grain-size distribution when their percentage is lower than 2%. Thus, there is no use to remove them from marine sediments before laboratory grain-size analysis of terrigenous particles. Additionally, ultrasonic is not suggested through the whole process of terrigenous grain-size analysis because the strong energy of ultrasonic can lead to the fragmentation of some fragile terrigenous particles.

The classification and influencing factors of modern marine productivity were reviewed at the beginning. We discussed the pros and cons of different paleoproductivity proxies. Based on these discussions, we collected paleoproductivity reconstructions in tropical marine from previous studies and focus on the glacial-interglacial features, periodicity and forcing mechanisms of tropical marine productivity. We found that the productivity in most tropical sites decreased from MIS 2 to MIS 1. The productivity was not always higher in glacial: The glacial-interglacial pattern of productivity turned at MIS 22 in western Pacific. There were remarkable differences between tropical productivity and high latitude productivity. The precession and obliquity bands were more significant in tropical productivity and ~30 ka cycles caused by the superimposing of different orbital cycles were common in tropical. The coccolith based productivity seemed to have a quasiperiod of 400 ka and more researches are needed to discover the relationship between productivity and global ¹³C in this band.

We analyzed the clay mineral assemblages, content and mineralogical characteristics of Hole U1438A sediment recovered from Amami Sankaku Basin during International Ocean Discovery Program (IODP) expedition 351. The results show that the clay minerals are mainly composed of illite (average 57%), smectite (average 26%), chlorite (average 14%) and minor kaolinite(average 3%). The crystallinity of illite in all samples are good (<0.4 Δ° 2θ), and the chemical indexes of illite in all samples are low (<0.4). Both indicate that illite in Hole U1438A formed in cold and dry climate. By comparing clay mineral assemblages of hole U1438A and the potential sediment sources, we suggest that smectite be mainly derived from the volcanic materials around Amami Sankaku Basin. Illite, chlorite and kaolinite are mainly derived from the Asian dust. The ratios of (illite+chlorite)/smectite show a phased increase over the last 350 ka, which is consistent with the cold and drying trend of the Asian continent since late Pleistocene. The high ratios of (illite+chlorite)/smectite and (illite+chlorite)/kaolinite during glacial period indicate that much more Asian dust was input into the Amami Sankaku Basin, which are responded to the aridity of Asian continent and strengthened east Asian Monsoon during glacial period.

The grain size composition of detrital sediments in Hole U1438A from the Amami Sankaku Basin(ASB) in the northwest of the Philippine Sea since the last 350 ka was analyzed. The result shows that the mean grain size of the detrital sediment is about 13.1 μm, ranging from 0.04 to 160 μm. The grain size distribution displays a four-peak pattern and positive skewness. Four independent grain size components were separated by using Weibull distribution function. The ultra-fine component varies from 0.04 to 0.9 μm, with a size mode at about 0.3 μm, which may be genetically related to marine authigenetic clay. The fine-grained fraction ranges from 0.2 to 32 μm, with a size mode at about 3.5 μm, and slightly coarser than the eolian dust of the North Pacific. We argued that this fraction was mainly derived from Asian dust. The coarse-grained and ultra-coarse-grained fractions show distinct size mode at about 10 μm and 40 μm, and range from 0.3 to 90 μm, and from 3 to 160 μm respectively. Both the coarse and ultra-coarse components represent volcanic materials which were mainly derived from the ridges and islands around ASB. The variation of the ratio of environmentally sensitive size population 1.3~2.2 μm/28~40 μm was similar with the ratio of fine-sized component (Asian dust) and coarse-sized component (volcanic material) (0.9~3 μm/>10 μm), showing higher value during glacial period than that during interglacial, which is also identical with the variation of the mass accumulation of eolian dust in the North Pacific and Chinese Loess Plateau, and grain size in Chinese Loess Plateau. The increased ratio responded to the enhanced aridity of Asian continent and strengthened East Asia Winter Monsoon (EAWM)/westerly during glacial period. We argued that the increase of eolian fraction was driven by the enhanced aridity of Asian continent and strengthened East Asia Winter Monsoon (EAWM)/westerly during glacial period. Therefore, the ratio of 0.9~3 μm/>10 μm can be used as a proxy of the increased aridity and enhanced atmospheric circulation of Asian continent. These results suggest that the grain size composition of the detrial sediment in the ASB can be used to reconstruct the history of Asian aridity and atmospheric circulation.

Sea level reconstruction is an important proxy for climate change. It can be compared with other reconstructed climatic factors as well as the results of the computer model-based reconstruction to offer a better recognition of the relationship between sea-level changes and other factors in the climate system. Oxygen isotope record obtained from calcium foraminiferal shell in deep-sea sediments contains global continental ice volume signal which can be used to reconstruct the evolution of paleo-sea level. Researchers reconstructed many long time scale and continuous records of sea level change by using foraminiferal oxygen isotope ratio data. In the future of paleo-sea level reconstruction, however, researchers need to contrast the sea level reconstruction with other climate proxy results to validate its accuracy and employ the interdisciplinary study method to acquire further development.

Intact Polar Lipids (IPLs) are synthesized predominately or uniquely by specific organisms and would degrade rapidly after cell death. Such biomarker IPLs can be used to indicate the microbial distribution and activity in marine environment. Here the progress of the aforementioned studies made over the last decade was reviewed. With the development of chromatography and mass spectrometry, the discovery of new IPLs compounds and the application of stable carbon isotope composition (δ¹³C) of IPLs, our understanding of the composition and transformation of IPLs in suspended particulate matter in the water column and of the applicability of the TEX₈₆ proxy are greatly improved. Besides, IPLs are widely applied in the study of marine eukaryotes-bacteria symbiosis, aerobic and anaerobic ammonia oxidation, anaerobic methane oxidation and microbial metabolic states. Meanwhile, it is suggested by recent studies that different IPLs often exhibit differential degradation. Some IPLs, especially glycolipids, have the potential to be preserved as fossil molecules for very long time upon dead cells, and therefore, they can not specifically indicate living biomass. Furthermore, the IPLs degradation rate and completeness would be affected by such factors as oxygen concentration and organic matter content. It is also suggested that the composition of IPLs might be affected by microbial metabolism. Therefore, it is essential to take these factors into account when IPLs are used as proxies to trace marine microbial activities and reconstruct the palaeoenvironment.

Magnetism is probably one of key disciplines for breakthrough of paleoenvironment studies in abyssal plain of the South China Sea. Magnetic susceptibility is the most basic and general parameter reflecting information of magnetic minerals in sediment, while ARM is sensitive to the concentration of singe domain particles which is main carrier of remanent magnetization. In this study, we explore the geological implications of magnetic susceptibility and Anhysteretic Remanent Magnetization (ARM) in core QD189 retrieved from abyssal plain of the South China Sea integrating the data of grain size and clastic mineral abundance. In the segments with magnetic susceptibility great than 45×10^-5 or the segments with depth less than 481 cm and magnetic susceptibility less than 45×10^-5, there are similar fluctuations among magnetic susceptibility, the contents of 2~5 ϕ grain size range, ARM, and ARM_@20mT , and the magnetic susceptibility changes in these segments is probably due to the fluctuations of contents of the soft magnetic multidomain grains within 2~5 ϕ grain size range. In the segments with depth from 808 cm to 488 cm and magnetic susceptibility less than 45×10^-5, the coherences among the changes of magnetic susceptibility, the contents of 2~5 ϕ grain size range, ARM, and ARM_@20mT are poor, and the mechanism of magnetic susceptibility changes is pending further research. 2~5 ϕ grain size range is an important coarse grain size component in QD189, and generally have a higher contents and bigger change ranges below the depth of 350 cm than above the depth of 350 cm. ARM_@20mT can more accurately indicate the concentration of singe domain particles in QD189 than ARM, and except single-domain particles, the particles of the pseudo-single-domain and multidomain within 9~12 ϕ grain size range probably make some indispensablet contributions to ARM in the segment with 665~48 cm depth, and a part of ARM in segment with 548~310 cm depth is also derived from multidomain within 6~9 ϕ grain size range. Six volcanic actions are recognized by the corresponds among the extreme peak values of clastic mineral abundance, volcanic glass abundance and magnetic susceptibility. The distribution pattern of volcanic glass abundance reveals the prevalence of bioturbation in QD189.

This paper summarizes previous studies of coccolithophores laboratory culture with emphasis on the application of cultured coccolithophores in the ecology, paleoceanography and petroleum. Because of the particular biology and physiology characteristics, coccolithophorid bloom can influence marine and atmosphere environment deeply , play an important roal in global carbon cycle and geological evolution. In the aspect of culture, we introduce the cultural method, the influence of cocolithophores growth by setting different environment parameters, the principle of suitable culture meduim depending on different research purpose. In the aspect of application, firstly, this paper discusses the physiological responses of coccolithophorids about ocean acidification. Then, coccolithophorid is high producer of DMSP(dimethylsulphoniopropionate)which can be divides into gas DMS, which can influence marine and atmosphere environment deeply through some chemical course. Further, another important application is the element geochemistry of coccoliths which is very meaningful in paleoceanography and paleoclimatology study. Finally, this paper also discusses the application of coccolithophores hydrocarbon generation to petroleum geology.

ODP Site 1144 is the only site for drilling into the sediment drift offshore Dongsha Islands, northern South China Sea. Integration of core and logging data from this site provides a good basis for reconstructing the rock physics model of the deep-sea sediment drift, which is of significance for understanding the relation between the lithological and elastic parameters of the deep-sea sediment and for the quantitative prediction of rock properties by reflection seismic data. The rock physical models for the deep-sea sediments are reviewed, including the Wood′s suspension model, the identical spherical grain contact model, and Sun′s velocity-porosity model for deep-sea sediments. Based on data of core smear slide analysis, the deep-sea sediments at Site 1144 are simplified as consisting of four major mineral components, which are clay minerals, which are carbonate, terrigenous clastic minerals and siliceous minerals, respectively. The elastic moduli and density of the latter three mineral components are substituted by using the corresponding values of their representative minerals, which are calcite, quartz, and opal; and the effective parameters of the clay minerals are determined by using the VoigtReuss-Hill and volume averaging, respectively. All the three rock physics models are applied into the deep-sea sediments at Site 1144 to estimate their P-wave velocity, which is then compared with that from the sonic logging. The result suggests that the estimated result  by  Sun′s model is most suitable to the measured result with the smallest error, that of Wood′s model matches the measured result in the shallow area but deviates from it with relative small error in the deep area, while that of the identical spherical grain contact model is overall higher than measured result  with relative big error.

Review the main works of IODP-China Scientific Committee since 2003. For ten years the Scientific Committee has done a large number of very fruitful work, especially proposed the strategy and plan for China participating in the activities of ocean drilling, organized various kinds of academic activities, and promoted the vigorous and healthy development of China’s deep-sea science and technology.

Integrated Ocean Drilling Program (IODP) expedition 344 was implemented from October 23 to December 11, 2012 in the offshore Costa Rica, which is known for the frequent occurrence of earthquakes. This expedition is part of the Costa Rica Seismogenesis Program (CRISP) that has an overarching goal of elucidating the origin, nucleation, and propagation of earthquakes in an erosive convergent margin. We participated in this expedition. Here we present numerous aspects of this expedition in this paper including tectonic settings of the drilling area, major scientific goals, field operation, preliminary results of this expedition, and post-cruise activities. More detailed and much in-depth research is  carried out after the cruise and post cruise results will be reported in the meeting to be held in Nanjing University in 2014. The synthesis of these new results should lead to better understanding of the seismogenesis of the study area.

Biogenic sulfides, an important type of biogenic minerals, are commonly form  in sea water and fresh water environment. They are actively involved in metal and sulfur biogeochemical cycles, and also may play a role in the origin of life on the early Earth. In modern natural settings, biogenic sulfides are closely associated with the activities of various organisms. Both microorganism and macrofauna can control or induce the formation of biogenic sulfides. Here, we review the latest research progresses in biogenic sulfides, related organisms, formation mechanism and relationship with the origin of life on the Earth.

The Southern Ocean CaCO₃ deposition not only records the processes of the biological pump modulating atmospheric CO₂, but also the changes in Southern Ocean surface frontal system and the structure of deep ocean circulation. CaCO₃% and its mass accumulation rate (MAR) changes at Tasman Sea site ODP 1170 during the past 2 Ma indicate a “Atlantic-style” feature with low CaCO₃% during glacials and high during interglacials. Three  sedimentary regimes are presented roughly bounded by MIS 34/35 (1.15 Ma BP) and MIS 14/15 (0.55 Ma BP); and the MAR-CaCO₃ represents five phases fluctuation. Cross-spectrum and wavelet analysis of CaCO₃% and orbital parameters ETP, and benthic  δ¹⁸O records show clear Mid-Pleistocene Transition (MPT) pattern of the main cyclicity transits from 40 ka to 100 ka, from 1.15 to 0.55 Ma BP. The changes in CaCO₃ deposition are closely related to the changes in Southern Westerlies and Antarctic Circumpolar Current（ACC） frontal system, and synchronous with the MPT. During the MPT, the rapid migration of the Southern Westerlies and ACC frontal system resulted in the dilution effect of siliceous deposition and terrigeneous input to the CaCO₃ deposition. The MAR-CaCO₃ variability is related to the changes in deepwater structure and its chemical properties. At 1.5~0.85 Ma BP, Southern Ocean deep water ventilation was enhanced, which favored the preservation of CaCO₃ and increased the MAR-CaCO₃; at  0.85~0.55 Ma BP, CO^2-₃ depleted Circumpolar Deep Water was enhanced, resulting in the dissolution of CaCO₃, and the rise of lysocline and decrease of MAR-CaCO_3.

Biomarker Glycerol Dialkyl Glycerol Tetraethers (GDGTs) was analyzed in 65 surface sediments from the Bering Sea and western Arctic Ocean recovered during the 3^rd and 4^th Chinese National Arctic Expeditions. The distribution patterns of isoprenoid and branched GDGTs concentration are divided by the Chukchi and Beaufort Sea Slope. GDGTs concentration is higher  in the   south of the slope than that in the north, which is controlled by water column productivity and terrestrial organic matter input. GDGTs based BIT suggests that terrestrial organic matter input increases from the north Chukchi Sea to Alpha Ridge, compared with marine organic matter, which is consistent with the results retrieved from organic carbon isotope ratios, suggesting that BIT is a reliable proxy in the Arctic Ocean. Sea Surface Temperatures (SST) derived by TEX^L₈₆ are not related to modern annual or summer mean SST, probably because of the mixed signal from terrestrial isprenoid GDGTs and low archaeal productivity in high Arctic region. Cyclisation ratio of Branched Tetraethers (CBT) show strong increase from seasonal sea ice area to permanent sea ice area, which may prove that CBT is sensitive to sea ice coverage. However, its mechanism remained unclear. Reconstructed terrestrial annual mean atmospheric temperature (MAT) and soil pH from branched GDGTs based CBT and Methylation index of Branched Tetraether (MBT) show extremely variability, which is probably affected by complicated sediment sources and soil mixing in transportation process.

As a crucial part of the global carbon cycle, microbially mediated anaerobic oxidation of methane (AOM) moderates the input of methane to the atmosphere and helps regulate Earth’s climate by consuming methane produced in various marine, terrestrial, and subsurface environments. It remains one of the most tantalizing and controversial scientific issues in both microbial ecology and environmental science since more than three decades when this process has been recognized. Recently, numerous researches have been carried out to investigate the reaction especially in the marine sediments associated with methane seeps. Unfortunately, there is still a gap to fully understand this reaction mechanism. In this paper, the recent progress in modern seafloor AOM including reaction mechanism, substrate, kinetics and energy yield, electron accepters and the involved methanotrophic archaea (ANME) and other microbes are reviewed. Furthermore, the role of AOM in environmental effects and climate changes in the past, present and future is illustrated and highlighted and the future challenges are given in the last part of this paper. We hope that this review will shed new light on an improved understanding of the AOM process in marine sediments.

Since the Industrial Revolution a large amount of carbon dioxide (CO₂) as a result of human activities has been released into the atmosphere. Dissolution of CO₂ into seawater reduced the ocean pH and changed the balance of the ocean carbonate system. Ocean acidification threatens the marine ecosystems, especially calcifying organisms. Coccolithophore are major calcification plankton and play an important role in the ocean carbon cycle. Most of the culture experiments showed that the rise of CO₂ concentration would promote photosynthesis in coccolithophores. Ocean acidification has various effects on the calcification of different coccolithophore species or strains.

 The analysis of foraminiferal B/Ca ratios is a greatly potential and widely concerned paleoceanographic method, which is applicable to the reconstruction of  the past pH and CO^2-₃  concentrations of sea water, and under certain situations also can also be used to reflect the changes of the atmospheric CO₂ concentration from surface water, and indicate changes of ocean current and water mass of deep water. Compared with the conventional method of boron isotopes, the B/Ca ratio method is relatively easier, more stable, and less  affected less by dissolution and postdeposition alternations. As a result, it is relatively suitable for highresolution paleoceanographic studies. However, this method is comparably new. The foraminiferal biological processes to absorb boron element is still not very clear. Moreover, the mechanisms using B/Ca ratio to reconstruct pH and CO^2-₃  concentrations is not well accepted. As the method is constructed on the basis of empirical function, establishment of its theoretical basis will be the future and important development of this method.

FMS formation micro-resistivity image logging, developed in 1986, was first used in scientific ocean drilling in 1989. It measures the electrical conductivity of borehole strata by using an array of pad-mounted button electrodes. The measured data are transformed into visual images reflecting variations of stratal details after a series of numerical and image processing steps. As high resolution (down to 5 mm), continuous and orientated in-situ measurements, FMS image logs provide an important supplement to core-based geological analysis in scientific ocean drilling, which is difficult to be replaced by other geophysical well loggings. The paper presents a review on the applications of FMS data to scientific ocean drilling, including core depth matching and core orientation, recognition of lithology and reconstruction of lithostratigraphic columns, sedimentary structures and paleo-current direction analysis, stratigraphic cyclicity and paleo-climate analysis, statistics of thickness distribution of turbidite beds, structural and stress analysis, as well as oceanic crust research. Some problems existing  in the analyses of the FMS data from ocean drilling are discussed, including low rate of utilization, insufficiency of quantitative analysis, and limited application scope and profundity.

Terrigenous components in sediment core B84A from the Alpha Ridge, western Arctic Ocean, have been investigated to reconstruct the Mid to Late Quaternary variations in sedimentation, source regions, and related climate changes. The core stratigraphy, evaluated by a combination of variations in Mn content, color cycles, foraminiferal abundance, and lithological correlation, extends back to estimated Marine Isotope Stage (MIS) 12. Twelve ice rafted detritus (IRD, >250 μm) events were identified and interpreted to mostly occur during the deglacial periods. The Canadian Arctic covered by ice sheets during glacial periods is suggested to be the major source region. The IRD events likely indicate the collapses of ice sheets, possibly in relation to abrupt climate changes. Grain size analysis of B84A indicates sedimentologically sensitive components in core B84A in the silt subfractions 4~9 μm and 19~53 μm, which are inferred to be mainly transported by currents and sea ice, respectively. Downcore variability of these two fractions may indicate changes in ice drift and current strength. In accordance with previous studies in the central Arctic Ocean, average sedimentation rate in core B84A is about 0.4 cm/ka. In comparison with relatively high sedimentation rates at the margins, sedimentation in the central Arctic Ocean is limited by sea ice cover and related low bioproductivity, as well as long distance from the source regions of terrigenous sediment.

Element geochemistry of coccoliths is very meaningful in paleoceanographic study, e.g.,Sr/Ca and Mg/Ca ratios. This paper summarizes previous studiesof coccolith Sr/Ca and Mg/Ca. According to previous studies, coccolith Sr/Ca ratio is mainly controlled by growth rates and calcification rates, secondly by temperature. While coccolith Mg/Ca ratio is influenced by temperature, but temperature relation differs among species. It is criticalto clean samples and separate monospecific coccoliths. Ion probe method is the most convenient and accurate analytical method. Coccolith Sr/Ca ratio can be used to indicatepaleoproductivity, and Mg/Ca to reconstruct paleotemperature. Element geochemistry has a great potential in paleoceanography and paleoclimatology. This paper also introduces the principle and analytical method of coccolith Sr/Ca and Mg/Ca in detail.

The South China Sea (SCS) has achieved rapid development and become an international hot spot in the paleoceanography study since the implementation of ODP Leg 184 in 1999. This paper attempts to review the progress, especially high revolution studies on the last 200 ka in the SCS, mainly relating to changes in sea surface temperature, salinity, productivity, and the upper ocean structure, as well as paleomonsoon records. Many SCS planktonic δ¹⁸O curves show different features from the global SPECMAP δ¹⁸O standard, with relatively low peaks at MIS5.5 and MIS7.3, but high peaks at MIS3.3 and MIS6.5, and can be called “monsoon-type planktonic δ¹⁸O curves”. In contrast to the SPECMAP δ¹⁸O standard prevailed by 100 ka cycles, the monsoon type planktonic δ¹⁸O curve is dominated by 20 ka precession cycle, representing the impact of monsoon precipitation. In addition, the complete records of rapid climate change events also reveal an important role played by tropical regions in rapid climate change.

The Iheya North Hydrothermal Field is located in the middle Okinawa Trough. During the Integrated Ocean Drilling Program (IODP) Expedition 331, the Deep Hot Biosphere Project, five sites (C0013~C0017) were drilled in the Iheya North Hydrothermal System from September 1 to October 4, 2010 in order to investigate metabolically diverse subseafloor microbial ecosystems and their physical and chemical settings. Site C0016 located in the active hydrothermal vent site and sulfide-sulfate mound at North Big Chimney (NBC) has the recovery rate of only 4.7%, but the core included the first Kuroko-type, sphalerite-rich black ore ever recovered from the modern seafloor. The other four sites yielded interbedded hemipelagic and volcaniclastic sediment and volcanogenic breccias and pumice that are variably hydrothermally altered and mineralized, in the zeolite to greenschist facies. Detailed temperature profiles at Sites C0014 and C0017 display irregularities suggestive of lateral flow.The analysis of interstitial water and headspace gas yielded complex patterns with depth and laterally at most sites over distances of only a few meters. Documented processes include formation of brines and vapor-rich fluids by phase separation and segregation, uptake of Mg and Na by alteration minerals in exchange for Ca, leaching of K at high temperature and uptake at low temperature, anhydrite precipitation, microbial oxidation of organic matter and anaerobic oxidation of methane utilizing sulfate, microbial methanogenesis. Shipboard analysis has not confirmed the presence of an active deep hot biosphere. Cell abundances are much lower than those found in previous Ocean Drilling Program/ IODP sites on continental margins, and attempts at culturing were generally unsuccessful.

The present contribution is a report submitted to the IODP-China office by the authors, after the implementation of the Integrated Ocean Drilling Program (IODP) Expedition 333. The objectives of this cruise are to drill at three sites along a transaction in the northern Philippine Sea, within the framework of the NanTroSEIZE program. The drilling operation was carried out from  December 12, 2010 to January 10, 2011, and cores with a total length of 1 005 m were obtained. These cores provide the materials to study the Quaternary sedimentary processes and mass transport deposits associated with the slope basin, deep trench and sea mount environments. Laboratory analyses will be carried out to obtain information on pore pressure within the sediment, heat flux, clay mineralogy, micro-structures, and tephra stratigraphy. On such a basis, the influence of the accretionary prism on the stress distribution and the critical stress for the occurrence of large-scale earthquakes may be evaluated. Furthermore, the cores enable the researchers to seek solutions to other scientific problems, such as the formation of deep water fine-grained sediment deposits, periodicity of volcano activities, the mechanisms for the formation deep sea green muds, the vertical distribution patterns of sedimentary structures and the related processes,  deep water sediment transport processes and the resultant geomorphological evolution during the Quaternary period.

The Costa Rica Seismogenesis Project (CRISP) (IODP Expedition 334) was carried out on the continental margin slope apron in the Costa Rica subduction zone in Central America during March 13 to April 13, 2011. The primary scientific goals of this expedition are to understand the processes that control nucleation and seismic rupture of large earthquakes at erosion-controlled subduction zone. During one month drilling, onboard totally 1492.88 meters long cores were obtained at four sites and eight holes. Tephra layers with ages ranging from Miocene to present were indentified. Rock variation characteristic of sediments and basement rocks were preliminary defined and basalt from the oceanic Cocos ridge basement was recovered.

Mg/Ca-thermometer is one of the most rapidly developed and as well widely used tools to reconstruct paleo-seawater temperatures in the last decade. There is, however, a growing body of evidence showing that the thermometer is significantly biased by a variety of factors. Of them, salinity effect on Mg uptake into biogenic shell calcites is most recently highlighted, with intensive discussions on the “fidelity” of the Mg/Ca-thermometer in reconstructing paleo-seawater temperature, and in turn in calculating salinity when combining Mg/Ca and oxygen isotope on a same foraminiferal sample. In this article, we reviewed the most recent publications with respect to salinity effects on Mg/Ca-thermometer and summarized solutions and/or methods to correct for salinity effects. The objective of this article is to provide helpful and state-of-the-art references for scientists within the country who are engaged in paleoceanographic study using Mg/Ca-thermometer.

Monterey Accelerated Research System (MARS) is a main test bed for the deep-sea observatory instruments in the world. On April 14 th, 2011, a China node, which consists of a junction box, a chemical environment system and a dynamical environment system, was  installed on MARS successfully by R/V Western Flyer, R/V Point Lobos and ROV Ventana for long-term test at the seafloor of Monterey Bay. China became the third country who tested her deep-sea observatory instruments on MARS on a large scale. Up to date, China node works well on MARS. The instruments of China node are sending data back from the seafloor of Monterey Bay. China node test on MARS shows that Chinese observatory technologies have had great progresses in the recent four years, which can be applied to the construction of the deep-sea observatory in China. Real-time data from China node will benefit marine research and show great advantages of deep-sea observatory.

Hydrothermal Fe-Si oxide deposits are ubiquitous in the hydrothermal vent sites at mid-ocean ridge and back-arc seafloor spreading centers. According to the recognitions of micron-scale filamentous textures and the results of molecular biology, neutrophilic Fe-oxidizing bacteria including Gallionella ferruginea, Leptothrix ochracea and the novel Mariprofundus ferrooxydans (PV-1 Strain) are considered to have a significant role in the formations of Fe-Si oxides deposits of the hydrothermal systems. These bacteria are capable of autotrophic metabolism with Fe²⁺as the sole electron donor,  increas the rate of Fe²⁺oxidation, and  then get energy for their growth. Electrostatic attraction along with the organic functional groups lead to the precipitations of iron oxides on the surface of abundant filamentous microbial structure that closely resemble the morphology of the Fe-oxidizing bacteria. Then the filaments were combined together to form a three-dimensional network. Novel observations were made of the Fe-Si framework of the network revealing the composite structure of Fe-rich filamentous in the core and the pure opal crust in the outer to form the “two-generation structure”. This indicates that the large-scale silica precipitation caused by conductive cooling  often takes place after the construction of the network. Recent studies about the Banded Iron Formations (BIF)  considered to be the analog of modern hydrothermal Fe-Si deposits  indicate an ancient hydrothermal origin for the iron. Moreover, owing to the pervasive anoxic state when the BIFs formed, the photosynthetic organisms for instance,  cyanobacteria  and the neutrophilic Fe-oxidizing bacteria are proposed to be involved in the ancient BIFs formations. 

The extreme physicochemical conditions of deep sea hydrothermal system have raised special ecosystem that barely depends on sunlight. This kind of ecology is supported by chemoautotrophic microorganisms, which are primary producers in hydrothermal system. Iron oxidizing bacteria is one of such microorganisms in seafloor hydrothermal environment, and they can gain energy through chemical reaction that oxidizes ferrous iron. They have important influence on the process of seafloor biogeochemical cycles, the formation of metal deposit and enrichment of the ecosystem functions in the deep sea hydrothermal environment. This paper is about the iron oxidizing bacteria that widely exist in deep sea hydrothermal environment, as well as their classification, mechanisms for oxidizing iron and the concomitant biomineralization phenomena. 

To study the archaeal diversity of deep-sea sediments in the tropical Western Pacific, we investigated the archaeal community structure in six sediments subsamples along the MD3059 sediment core collected during the IMAGES ⅪⅤ cruise with 16S rDNA analysis. A total of 543 archaeal 16S rDNA clones were examined and a total of 137 OTUs were obtained. Phylogenetic results showed that the archaeal diversity in the collected samples was very diverse, and the obtained OTUs were grouped into Crenarchaeota and Euryarchaeota, with the former dominated by Miscellaneous Crenarchaeotic Group (MCG, 54% of total archaeal clones) and the latter dominated by Marine Benthic Group D (MBG-D), South African Gold Mine Euryarchaeotic Group (SAGMEG) and Marine Benthic Group B (MBG-B). These data have important implications for our understanding of archaeal community in deep-sea sediments of the tropical Western Pacific.

Formation Microscanner Service (FMS) is an advanced logging technology. Because of its advantages of high resolution and intuition, FMS measurement has been used in the recovery of original dip direction of structural elements, and that of sedimentary beddings. The Shatsky Rise is a key study area during the IODP Expedition 324. After FMS processing for Holes U1347A, Hole U1348A and Hole U1349A, interpretations of geological structures and their dip directions are discussed in this paper. We conclude that the formation of the TAMU Massif is consistent with the seafloor spreading theory while the formation of the Ori Massif has no obvious preferred stress field, being deduced to be related to a mantle plume head. 

Direct observations and measurements on deformational and sedimentary structures, fluid activities, physical properties, and chemical compositions of core samples from accretionary prisms at different pressure and temperature settings are critical to understanding seismogenic mechanisms of subduction zone earthquakes. Based on core measurements from IODP expedition 316 of the first stage of the NanTroSEIZE program, we analyze deformational and sedimentary structures at the core scale at four sites, C0004, C0006, C0007 and C0008, at the toe the accretionary prism along the Nankai Trough. We also discuss the relationships between structures at the core scale and large scale structures like splay fault and frontal thrust fault. It is found that thrusting deformation in the accretionary prism is accommodated not only by deformation within large-scale thrusting zones, but also by deformation along secondary thrusts and potentially more importantly along core-scale structures such as micro-faults and deformation bands. The consistencies in dipping angles between large scale thrusts and core-scale structures indicate that structures at different scales are formed under a unified stress field within the accretionary prism. At the shallow part of the accretionary prism, high angle normal faults dominate, showing extensional stress field, and beddings and fissilities from core samples show trends and high dips consistent with those estimated from seismic stratigraphy and regional structures. At deeper parts, particularly near the large scale thrusts, faults of all types, joints and deformation bands are common features, and beddings and fissilities show vertiginous attitudes controlled preferably more by large scale thrusting deformation.

Total DNA was extracted from the top sediment layer (0-10 cm) of MD06-3047 in the Kuroshio and was used as template for polymerase chain reaction (PCR) amplification employing specific primers for bacterial and archaeal 16S rRNA genes. The 16S rDNA libraries were then constructed. Microbial diversity was analyzed by using restriction fragment length polymorphism (RFLP), DNA sequencing and phylogenetic analysis. The results show that there are six phyla in the Bacteria domain: Proteobacteria, Acidbacterium, Planctanycenea, Verrucomicrobia, Candidate division OP8 and Bacteroidetes, and the phylum Proteobacteria is predominant. In the Archaea domain, Crenarchaeota dominates over Euryarchaeota. There are four divisions in the Crenarchaeota kingdom: MCG, C₃, Marine Benthic Group A, Marine Group;  three divisions in Euryarchaeota kingdom: South Africa Golden mine Euryarchaeota Group、Marine Benthic Group E and MEG, and the Marine Benthic Group E is the dominating group. 

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Oceanic current plays a key role in controlling the redistribution of global heat and moisture, which may have effect on climatic change finally. It′s urgent to understand the mechanism of ocean current evolution, which may be related to alternation between warm and cold weather, and to better predict the trend of present climatic change. It has been confirmed that the Nd isotopic composition is an effective proxy for studying ocean current evolution, and has attracted many attentions. This paper interprets why the Nd isotopic composition could be used as a proxy to reconstruct paleocirculation through illustrating the characteristic of Nd. Besides, some materials enriched in Nd and methods for studying will be explained in detail.

Cold seeps are typical areas abundant both in marine energy resources and biological resources. Benthic foraminiferal assemblages and the geochemical composition of their carbonate shells, such as δ¹³C, are important indicators of cold seep. These proxies have important significances in the study of the paleo-cold seeps evolution, and also in the evaluation study of methane released from cold seeps and their effects on global climate changes. This paper reviews the methods and recent progress in cold seep benthic foraminiferal studies in some modern active cold seeps. Through comparison the main characteristics of modern cold seep benthic foraminiferal faunal and the discrepancy between different seepages are presented. It also reviews the carbon isotope response of benthic foraminifera in different cold seep areas and its possibly influential factors. Finally we give a general outlook for the study of cold seep benthic foraminifera in the northern South China Sea.