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
The Dahongliutan granitic pluton,in the eastern part of the West Kunlun orogenic belt,provides significant insights for studying the tectonic evolution of West Kunlun.This paper presents a systematic study of LA-ICP-M...The Dahongliutan granitic pluton,in the eastern part of the West Kunlun orogenic belt,provides significant insights for studying the tectonic evolution of West Kunlun.This paper presents a systematic study of LA-ICP-MS zircon U Pb age,major and trace elements,Sr-Nd-Hf isotopes,and the first detailed Li isotope analysis of the Dahongliutan pluton.LA-ICP-MS zircon U Pb dating shows that the Dahongliutan granites were emplaced in the Late Triassic((213±2.1)Ma).Geochemical data show relatively high SiO2 contents(68.45 wt%73.62 wt%)and aluminum saturation index(A/CNK=1.111.21)indicates peraluminous high-K calc-alkaline granite.The Dahongliutan granites are relatively high in light rare earth elements(LREE)and large ion lithophile elements(LILEs)(e.g.,Rb,K,Th),and relatively depleted in high field strength elements(HFSEs)(e.g.,Nb,Ta,P,Ti).TheεNd(t)values range from 8.71 to 4.73,and(87Sr/86Sr)i=0.70870.71574.Zircons from the pluton yield 176Hf/177Hf values of 0.2826181 to 0.2827683,andεHf(t)values are around 0;the two-stage Hf model ages range from 0.974 to 1.307 Ga.Theδ7Li values are 0.76‰3.25‰,with an average of 2.53‰.Isotopic compositions of the pluton suggest a mixed trend between the partial melting of the Middle Proterozoic ancient crustal material and a juvenile mantle-derived material.This study infers that the Dahongliutan rock mass is formed in the post-collisional extension environment,when the collision between South Kunlun and the Tianshuihai terranes results in the closure of the Palaeo-Tethys.The mantle-derived magma results in partial melting of the lower crust.展开更多
The cultural and geomorphological heritages in Playas as a key address to find out past fluctuations called geotop. Iran is strategically located on an important trade route （Silk Road） between four cradles of civil...The cultural and geomorphological heritages in Playas as a key address to find out past fluctuations called geotop. Iran is strategically located on an important trade route （Silk Road） between four cradles of civilization namely, Babylon, Mesopotamia, Indus and Yangtze （Chinese）. Iran is grafting point of four human civilizations which creates Persian civilization about 4,000 years ago. The Lut Desert and Dasht-e Kavir located the central and eastern Iran have been focal points for human settlements since 7,000 years ago. The geoarcheological findings on the Siyalk hills of Kashan located in the Dasht-e Kavir and Jiroft region located in the Lut desert are confirmations for human settlement since more than 7,000 years ago. Shorehzar that is a Persian equivalent word for Arabic word of Sabkha is considered as a Playa geomorphic type which involves precious evidences of quaternary fluctuations. In this article, geomorphological and paleoenvironmental investigations are integrated to provide a framework of environmental change for the late Pleistocene and early-mid Holocene periods in the main deserts of Iran, Lut. In this article based on main geotops of Lut, the quaternary evolutions have been discussed. The investigations are showing that Playas were bed of civilization in Iran Deserts.展开更多
The shape,texture,content and REE characteristics of zircons from the O2tnd-1,O3tnd-2,O3tnd-3pyroclastic rock of Tanjianshan Group on the north margin of Qaidam Basin indicate that the O2-3tndis the product of volcani...The shape,texture,content and REE characteristics of zircons from the O2tnd-1,O3tnd-2,O3tnd-3pyroclastic rock of Tanjianshan Group on the north margin of Qaidam Basin indicate that the O2-3tndis the product of volcanism during the transitional period from ocean-land interim crust to oceanic crust.The U-Pb surface ages obtained from O3tnd-2and O3tnd-3can be divided into 9 groups,every age group coincides with the period when significant tectonic-heat event took place at Oulongbuluke micro-continental base of northern Qaidam,suggesting that the base rocks have provided materials for the formation of sedimentary and volcanic rock in O2-3tnd.The volcanic rocks of O3tnd-3formed at 440 Ma,with time gap 46 Ma to those of O1tna-1and O3tnd-3may represent the minor period that Xitieshan back-arc extension have lasted,the scale of back-arc basin that formed in Xitieshan extension may approach to 1 400 km.Based on the test of ithochemistry data for major elements and analysis of Sr isotope geochemistry for the clastic sedimentary rock in O1tna-2and O3tnd-2,the authors get the conclusion that the O1tna-2and O3tnd-2of Tanjianshan Group may form in back-arc basin environment,while the lithology difference between these two formations may reflect the changes of geodynamic processes as the diagenesis tectonic environment transformed from continental margin depression to adjacent sea basin.展开更多
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.
基金Project(2017YFC0602701)supported by the National Key Research and Development Plan,ChinaProject(DD20160004-8-3)supported by the Geological Survey of China
文摘The Dahongliutan granitic pluton,in the eastern part of the West Kunlun orogenic belt,provides significant insights for studying the tectonic evolution of West Kunlun.This paper presents a systematic study of LA-ICP-MS zircon U Pb age,major and trace elements,Sr-Nd-Hf isotopes,and the first detailed Li isotope analysis of the Dahongliutan pluton.LA-ICP-MS zircon U Pb dating shows that the Dahongliutan granites were emplaced in the Late Triassic((213±2.1)Ma).Geochemical data show relatively high SiO2 contents(68.45 wt%73.62 wt%)and aluminum saturation index(A/CNK=1.111.21)indicates peraluminous high-K calc-alkaline granite.The Dahongliutan granites are relatively high in light rare earth elements(LREE)and large ion lithophile elements(LILEs)(e.g.,Rb,K,Th),and relatively depleted in high field strength elements(HFSEs)(e.g.,Nb,Ta,P,Ti).TheεNd(t)values range from 8.71 to 4.73,and(87Sr/86Sr)i=0.70870.71574.Zircons from the pluton yield 176Hf/177Hf values of 0.2826181 to 0.2827683,andεHf(t)values are around 0;the two-stage Hf model ages range from 0.974 to 1.307 Ga.Theδ7Li values are 0.76‰3.25‰,with an average of 2.53‰.Isotopic compositions of the pluton suggest a mixed trend between the partial melting of the Middle Proterozoic ancient crustal material and a juvenile mantle-derived material.This study infers that the Dahongliutan rock mass is formed in the post-collisional extension environment,when the collision between South Kunlun and the Tianshuihai terranes results in the closure of the Palaeo-Tethys.The mantle-derived magma results in partial melting of the lower crust.
文摘The cultural and geomorphological heritages in Playas as a key address to find out past fluctuations called geotop. Iran is strategically located on an important trade route （Silk Road） between four cradles of civilization namely, Babylon, Mesopotamia, Indus and Yangtze （Chinese）. Iran is grafting point of four human civilizations which creates Persian civilization about 4,000 years ago. The Lut Desert and Dasht-e Kavir located the central and eastern Iran have been focal points for human settlements since 7,000 years ago. The geoarcheological findings on the Siyalk hills of Kashan located in the Dasht-e Kavir and Jiroft region located in the Lut desert are confirmations for human settlement since more than 7,000 years ago. Shorehzar that is a Persian equivalent word for Arabic word of Sabkha is considered as a Playa geomorphic type which involves precious evidences of quaternary fluctuations. In this article, geomorphological and paleoenvironmental investigations are integrated to provide a framework of environmental change for the late Pleistocene and early-mid Holocene periods in the main deserts of Iran, Lut. In this article based on main geotops of Lut, the quaternary evolutions have been discussed. The investigations are showing that Playas were bed of civilization in Iran Deserts.
基金Supported by the National Natural Science Foundation of China(No.41172087)the Fundamental Research Funds for the Central Universities(No.CUG090102)
文摘The shape,texture,content and REE characteristics of zircons from the O2tnd-1,O3tnd-2,O3tnd-3pyroclastic rock of Tanjianshan Group on the north margin of Qaidam Basin indicate that the O2-3tndis the product of volcanism during the transitional period from ocean-land interim crust to oceanic crust.The U-Pb surface ages obtained from O3tnd-2and O3tnd-3can be divided into 9 groups,every age group coincides with the period when significant tectonic-heat event took place at Oulongbuluke micro-continental base of northern Qaidam,suggesting that the base rocks have provided materials for the formation of sedimentary and volcanic rock in O2-3tnd.The volcanic rocks of O3tnd-3formed at 440 Ma,with time gap 46 Ma to those of O1tna-1and O3tnd-3may represent the minor period that Xitieshan back-arc extension have lasted,the scale of back-arc basin that formed in Xitieshan extension may approach to 1 400 km.Based on the test of ithochemistry data for major elements and analysis of Sr isotope geochemistry for the clastic sedimentary rock in O1tna-2and O3tnd-2,the authors get the conclusion that the O1tna-2and O3tnd-2of Tanjianshan Group may form in back-arc basin environment,while the lithology difference between these two formations may reflect the changes of geodynamic processes as the diagenesis tectonic environment transformed from continental margin depression to adjacent sea basin.
