The composition of mantle-derived basalts reflects the nature of their mantle source regions,which constrain magma generation and composition.Here we present a new whole rock major and trace elements and phenocryst co...The composition of mantle-derived basalts reflects the nature of their mantle source regions,which constrain magma generation and composition.Here we present a new whole rock major and trace elements and phenocryst composition of the basaltic lava in the central Mariana Trough.These data provide insights into the mantle source characteristics affected by subduction components.The rocks range from basalts to basaltic andesites,which have high subduction-mobile element contents(e.g.,K,U,Th,LREE)related to N-MORB.The calculated temperature and depth of magma generation are about 1300℃and 30 km,respectively.Although the results above suggest that the addition of hydrous fluid and/or a melt derived from a slab decreases the temperature of mantle partial melting and mildly modifies the composition of a mantle source,the mantle source lithology from which primary magma is generated remains to be peridotite.展开更多
[目的]运动改善超重或肥胖人群的血压对心血管疾病的预防有重要意义.比较健康肥胖或超重成人采用高强度间歇训练(HIIT)和中等强度持续训练(MICT)对舒张压(DBP)和舒张压(SBP)的影响.[方法]通过检索PubMed、Cochrane、Web of Science与CNK...[目的]运动改善超重或肥胖人群的血压对心血管疾病的预防有重要意义.比较健康肥胖或超重成人采用高强度间歇训练(HIIT)和中等强度持续训练(MICT)对舒张压(DBP)和舒张压(SBP)的影响.[方法]通过检索PubMed、Cochrane、Web of Science与CNKI数据库,共纳入文献12篇.纳入文献中HIIT与MICT组总样本量均为151个.采用随机效应模型(Random-effects Model)进行Meta分析.[结果]HIIT vs.MICT对超重/肥胖成人DBP、SBP无显著差异;[18,35]岁的亚组MICT改善BDP效果显著性优于HIIT,间歇时间小于2 min的HIIT亚组HIIT效果显著性优于MICT.[结论]对健康超重或肥胖成人在改善血压方面HIIT是高效的运动方式;年龄和训练周期影响HIIT和MICT改善血压的效果,在年龄低于35岁的人群中,MICT改善DBP的效果优于HIIT,间歇时间小于2 min的HIIT训练方式改善DBP效果低于MICT.展开更多
The previous studies of the sedimentology and chronology of sediment core SYS-0701, which was recovered from the western South Huanghai Sea （Yellow Sea）, have revealed the changes in the sea-level and sedimen- tary ...The previous studies of the sedimentology and chronology of sediment core SYS-0701, which was recovered from the western South Huanghai Sea （Yellow Sea）, have revealed the changes in the sea-level and sedimen- tary evolution during the late Quaternary in the region. The present study used mineralogical data from the section of the core deposited since Marine Isotope Stage （MIS） 3, to decipher the provenance of sediments of the paleo-delta deposited during MIS 3 and MIS 1. Based on the lithologic features and the variations with depth of the concentrations of carbonates and both heavy and light minerals in bulk samples, the up- per part of Core SYS-0701 can be divided into three units designated DU1, DU4, and DU5, in accord with previouslyused terminology. Sub-units of units DU1 （DU1-1 and DU1-2） and DU4 （DU4-1 and DU4-2） have also been identified. DU1 was deposited during MIS 1, and DIJ4 and DU 5 were formed during MIS 3. All data pertaining to dominant heavy mineral assemblages, diagnostic minerals, ratios of diagnostic minerals, light mineral associations, textural maturities, and carbonate contents, indicate that the sediments of Core SYS-0701 are comparable with Huanghe River （Yellow River） sediments. Moreover, the mineralogy of the sediment evidenced its dependence on supply rates and hydrodynamic conditions. Weak hydrodynamics （DU5 and DU4-2） and/or low sediment supply （DU1-2） led to sediment containing less hornblende and epidote, with a large specific gravity and high content of flaky minerals, and vice versa in cases of strong hydrodynamics （DIJ4-1） and very large sediment supply （DUI-1）.展开更多
Seafloor elongated depressions are indicators of gas seepage or slope instability. Here we report a sequence of slopeparallel elongated depressions that link to headwalls of sediment slides on upper slope. The depress...Seafloor elongated depressions are indicators of gas seepage or slope instability. Here we report a sequence of slopeparallel elongated depressions that link to headwalls of sediment slides on upper slope. The depressions of about 250 m in width and several kilometers in length are areas of focused gas discharge indicated by bubble-release into the water column and methane enriched pore waters. Sparker seismic profiles running perpendicular and parallel to the coast, show gas migration pathways and trapped gas underneath these depressions with bright spots and seismic blanking. The data indicate that upward gas migration is the initial reason for fracturing sedimentary layers. In the top sediment where two young stages of landslides can be detected, the slopeparallel sediment weakening lengthens and deepens the surficial fractures, creating the elongated depressions in the seafloor supported by sediment erosion due to slope-parallel water currents.展开更多
This article presents the evidence in support of the direct magma degassing as the principal mechanism of volatiles releasing into the hydrothermal fluids in the Okinawa Trough, as contrasted to the argument for the h...This article presents the evidence in support of the direct magma degassing as the principal mechanism of volatiles releasing into the hydrothermal fluids in the Okinawa Trough, as contrasted to the argument for the hydrothermal stripping of volatiles from the volcanic rocks.\ Laser Raman microprobe and stepped-heating techniques are employed to determine the compositions and contents of the volatiles in pumices in the middle Okinawa Trough. The results show that the volatiles are similar to the gases in the hydrothermal fluids and hydrothermal minerals in composition, the mean percent content of each component and variation trend. This indicates the direct influence of magma degassing on the hydrothermal fluids. In addition, the contents of volatiles in pumices are rather low and do not support the hydrothermal stripping as the main mechanism to enrich the fluids with gases. The results are consistent with the idea that the direct magma degassing is more important than hydrothermal stripping in supplying gases to the hydrothermal fluids in the Okinawa Trough.展开更多
The oxygen fluxe across the sediment-water interface(SWI)in coastal region is a key measure to fully understand the regulation of biogeochemical cycles in an aquatic environment.However,studies on fluxes of dissolved ...The oxygen fluxe across the sediment-water interface(SWI)in coastal region is a key measure to fully understand the regulation of biogeochemical cycles in an aquatic environment.However,studies on fluxes of dissolved oxygen in gravel beach are limited,because of the difficulty in sample collection and instrumentations deployment.In this study,benthic oxygen fluxes across rocky substratum in an intertidal zone of Huiquan Bay was estimated by using noninvasive eddy correlation techniques.A total of 10 burst measurements were analyzed.The oxygen flux fluctuated from-5.7888±2.6 to+49.3344±2.6 mmol O2 m-2/d were observed.The cospectra analysis showed that the oxygen flux at the frequency band between 0.093 and 0.279 Hz(at a period from 3.58 to 10.75 s)contributed 50.19%to the total spectrum on average.The results showed that the major contribution band moved to the high frequency region gradually and reached a steady state with increasing tidal flood.It is demonstrated that wave movement and wave breaking interaction resulted in the change of oxygen flux between gravel beach and shallow waters at the start and the end of a rising tide period,respectively.The eddy correlation techniques offer an efficient means for flux measurement over a gravel or mixed sand and gravel beaches.展开更多
基金the Shandong Provincial Natural Science Foundation,China(Nos.ZR2017PD002 and ZR2019BD010)the Open Fund of the Key Laboratory of Marine Geology and Environment,Chinese Academy of Sciences(Nos.MGE2019KG05 and MG E2021KG01)the Fundamental Research Funds for the Central Universities(No.202051009)。
文摘The composition of mantle-derived basalts reflects the nature of their mantle source regions,which constrain magma generation and composition.Here we present a new whole rock major and trace elements and phenocryst composition of the basaltic lava in the central Mariana Trough.These data provide insights into the mantle source characteristics affected by subduction components.The rocks range from basalts to basaltic andesites,which have high subduction-mobile element contents(e.g.,K,U,Th,LREE)related to N-MORB.The calculated temperature and depth of magma generation are about 1300℃and 30 km,respectively.Although the results above suggest that the addition of hydrous fluid and/or a melt derived from a slab decreases the temperature of mantle partial melting and mildly modifies the composition of a mantle source,the mantle source lithology from which primary magma is generated remains to be peridotite.
基金The National Natural Science Foundation of China under contract No.40876034MLR Geologic Survey Project under contract Nos 1212010611401 and 1212010911072
文摘The previous studies of the sedimentology and chronology of sediment core SYS-0701, which was recovered from the western South Huanghai Sea （Yellow Sea）, have revealed the changes in the sea-level and sedimen- tary evolution during the late Quaternary in the region. The present study used mineralogical data from the section of the core deposited since Marine Isotope Stage （MIS） 3, to decipher the provenance of sediments of the paleo-delta deposited during MIS 3 and MIS 1. Based on the lithologic features and the variations with depth of the concentrations of carbonates and both heavy and light minerals in bulk samples, the up- per part of Core SYS-0701 can be divided into three units designated DU1, DU4, and DU5, in accord with previouslyused terminology. Sub-units of units DU1 （DU1-1 and DU1-2） and DU4 （DU4-1 and DU4-2） have also been identified. DU1 was deposited during MIS 1, and DIJ4 and DU 5 were formed during MIS 3. All data pertaining to dominant heavy mineral assemblages, diagnostic minerals, ratios of diagnostic minerals, light mineral associations, textural maturities, and carbonate contents, indicate that the sediments of Core SYS-0701 are comparable with Huanghe River （Yellow River） sediments. Moreover, the mineralogy of the sediment evidenced its dependence on supply rates and hydrodynamic conditions. Weak hydrodynamics （DU5 and DU4-2） and/or low sediment supply （DU1-2） led to sediment containing less hornblende and epidote, with a large specific gravity and high content of flaky minerals, and vice versa in cases of strong hydrodynamics （DIJ4-1） and very large sediment supply （DUI-1）.
基金funded by the European project EUROFLEETS (Seventh Framework Programme, No. 228344)
文摘Seafloor elongated depressions are indicators of gas seepage or slope instability. Here we report a sequence of slopeparallel elongated depressions that link to headwalls of sediment slides on upper slope. The depressions of about 250 m in width and several kilometers in length are areas of focused gas discharge indicated by bubble-release into the water column and methane enriched pore waters. Sparker seismic profiles running perpendicular and parallel to the coast, show gas migration pathways and trapped gas underneath these depressions with bright spots and seismic blanking. The data indicate that upward gas migration is the initial reason for fracturing sedimentary layers. In the top sediment where two young stages of landslides can be detected, the slopeparallel sediment weakening lengthens and deepens the surficial fractures, creating the elongated depressions in the seafloor supported by sediment erosion due to slope-parallel water currents.
基金This work was supported by the Major State Basic Research Program(No.G2000078503)Shandong Natural Science Foundation(No.Y2000E06).
文摘This article presents the evidence in support of the direct magma degassing as the principal mechanism of volatiles releasing into the hydrothermal fluids in the Okinawa Trough, as contrasted to the argument for the hydrothermal stripping of volatiles from the volcanic rocks.\ Laser Raman microprobe and stepped-heating techniques are employed to determine the compositions and contents of the volatiles in pumices in the middle Okinawa Trough. The results show that the volatiles are similar to the gases in the hydrothermal fluids and hydrothermal minerals in composition, the mean percent content of each component and variation trend. This indicates the direct influence of magma degassing on the hydrothermal fluids. In addition, the contents of volatiles in pumices are rather low and do not support the hydrothermal stripping as the main mechanism to enrich the fluids with gases. The results are consistent with the idea that the direct magma degassing is more important than hydrothermal stripping in supplying gases to the hydrothermal fluids in the Okinawa Trough.
基金Funding for this work was supported by the National Natural Science Foundation of China (Nos. 41276089, 41176078)the National High-technology research and development Program of China (‘863’Program) (Nos. 2012AA09A20103, 2009AA09Z201)
文摘The oxygen fluxe across the sediment-water interface(SWI)in coastal region is a key measure to fully understand the regulation of biogeochemical cycles in an aquatic environment.However,studies on fluxes of dissolved oxygen in gravel beach are limited,because of the difficulty in sample collection and instrumentations deployment.In this study,benthic oxygen fluxes across rocky substratum in an intertidal zone of Huiquan Bay was estimated by using noninvasive eddy correlation techniques.A total of 10 burst measurements were analyzed.The oxygen flux fluctuated from-5.7888±2.6 to+49.3344±2.6 mmol O2 m-2/d were observed.The cospectra analysis showed that the oxygen flux at the frequency band between 0.093 and 0.279 Hz(at a period from 3.58 to 10.75 s)contributed 50.19%to the total spectrum on average.The results showed that the major contribution band moved to the high frequency region gradually and reached a steady state with increasing tidal flood.It is demonstrated that wave movement and wave breaking interaction resulted in the change of oxygen flux between gravel beach and shallow waters at the start and the end of a rising tide period,respectively.The eddy correlation techniques offer an efficient means for flux measurement over a gravel or mixed sand and gravel beaches.
