A total of 67 samples from the upper and lower sediment traps in the central South China Sea were analyzed, which were collected during 1993 ~ 1996. It is indicated that the distribution of stable isotope values, surf...A total of 67 samples from the upper and lower sediment traps in the central South China Sea were analyzed, which were collected during 1993 ~ 1996. It is indicated that the distribution of stable isotope values, surface primary productivity, fluxes of total particulate matter, carbonate, biogenic opal, organic carbon, planktonic foraminiferal species and their total amount exhibit obviously seasonal and annual fluctuations. High values of the fluxes occurred in the prevailing periods of the northeastern and southwestern monsoons, and the low values occurred during the periods between the two monsoons. The fluxes of some planktonic foraminiferal species （ Globigerinoides sacculifer , G. ruber , Globigerinita glutinata, Neogloboquadrina dutertrei ） and their percentages also exhibit two prominent peaks during the prevailing periods of the northeastern and southwestern monsoons respectively, while those of Globigerina bulloides, Globorotalia menardii and Pulleniatina obliquiloculata only exhibit one peak in the prevailing periods of the northeastern monsoon. In addition, fluxes and percentages of Globigerinoides sacculifer and Globorotalia menardii as well as the fluxes of carbonate and total amount of planktonic foraminifera decrease gradually from 1993 to 1996, and those of Globigerina bulloides, Globigerinita glutinata and biogenic opal increase gradually from 1993 to 1996. The fluxes of carbonate and organic carbon in the upper trap are higher than those in the lower one. The study indicates that the seasonal and annual variations of the sediment fluxes and planktonic foraminiferal species are mainly controlled by the changes of surface primary productivity and hydrological conditions related to the East Asian monsoon. The lower carbonate and organic carbon fluxes in the lower trap are related to the dissolution.展开更多
Heat flow was measured on the Lomonosov Ridge during the 5th Chinese National Arctic Expedition in 2012. To derive the time-temperature curve, resistivity data were transformed to temperature by the resistivity- tempe...Heat flow was measured on the Lomonosov Ridge during the 5th Chinese National Arctic Expedition in 2012. To derive the time-temperature curve, resistivity data were transformed to temperature by the resistivity- temperature program. Direct reading and linear regression methods were used to calculate the equilibrium temperature, which were regressed against the depth of the probes in sediment to derive the geothermal gradient. Then, heat flow was calculated as the product of geothermal gradient and thermal conductivity of sediments. The heat flow values on the basis of the two methods were similar （i.e., 67.27 mW/m2 and 63.99 mW/m2, respectively）. The results are consistent with the measurements carried out at adjacent sites. The age of the Lomonosov Ridge predicted by the heat flow-age model was 62 Ma, which is in accordance with the inference that the ridge was separated from Eurasia at about 60 Ma.展开更多
文摘A total of 67 samples from the upper and lower sediment traps in the central South China Sea were analyzed, which were collected during 1993 ~ 1996. It is indicated that the distribution of stable isotope values, surface primary productivity, fluxes of total particulate matter, carbonate, biogenic opal, organic carbon, planktonic foraminiferal species and their total amount exhibit obviously seasonal and annual fluctuations. High values of the fluxes occurred in the prevailing periods of the northeastern and southwestern monsoons, and the low values occurred during the periods between the two monsoons. The fluxes of some planktonic foraminiferal species （ Globigerinoides sacculifer , G. ruber , Globigerinita glutinata, Neogloboquadrina dutertrei ） and their percentages also exhibit two prominent peaks during the prevailing periods of the northeastern and southwestern monsoons respectively, while those of Globigerina bulloides, Globorotalia menardii and Pulleniatina obliquiloculata only exhibit one peak in the prevailing periods of the northeastern monsoon. In addition, fluxes and percentages of Globigerinoides sacculifer and Globorotalia menardii as well as the fluxes of carbonate and total amount of planktonic foraminifera decrease gradually from 1993 to 1996, and those of Globigerina bulloides, Globigerinita glutinata and biogenic opal increase gradually from 1993 to 1996. The fluxes of carbonate and organic carbon in the upper trap are higher than those in the lower one. The study indicates that the seasonal and annual variations of the sediment fluxes and planktonic foraminiferal species are mainly controlled by the changes of surface primary productivity and hydrological conditions related to the East Asian monsoon. The lower carbonate and organic carbon fluxes in the lower trap are related to the dissolution.
基金Expedition and Assessment of Environment in the Polar Area under contract Nos CHINARE 2012-03-03 and 2013-04-03the Polar Strategic Research Foundation under contract No.20100210Public Science and Technology Research Funds Projects of Ocean under contract No.200905024-3
文摘Heat flow was measured on the Lomonosov Ridge during the 5th Chinese National Arctic Expedition in 2012. To derive the time-temperature curve, resistivity data were transformed to temperature by the resistivity- temperature program. Direct reading and linear regression methods were used to calculate the equilibrium temperature, which were regressed against the depth of the probes in sediment to derive the geothermal gradient. Then, heat flow was calculated as the product of geothermal gradient and thermal conductivity of sediments. The heat flow values on the basis of the two methods were similar （i.e., 67.27 mW/m2 and 63.99 mW/m2, respectively）. The results are consistent with the measurements carried out at adjacent sites. The age of the Lomonosov Ridge predicted by the heat flow-age model was 62 Ma, which is in accordance with the inference that the ridge was separated from Eurasia at about 60 Ma.
