湘南西山铝质A型花岗质火山-侵入杂岩的地球化学及其形成环境   总被引：19，自引：1，他引：18  

付建明  马昌前  谢才富  张业明  彭松柏 《地球科学与环境学报》2004,26(4):15-23

初步研究表明,以往被认为是典型的S型花岗质岩石的湘南西山火山侵入杂岩应为铝质A型花岗质岩石。该杂岩富硅碱贫钙镁、K2O/Na2O>1、准铝过铝质(0.94～1.26);FeO /MgO比值大(平均12.05),高于M型,S型和I型花岗岩。在微量元素和稀土元素组成上,岩石富LREE,Ga,Y,Nb,Zr等大离子高场强元素及亏损Ni,Cr,Eu,Ti,V,P,Sr等,与国内外A型花岗岩相似。与一般A型花岗岩来源于I型花岗岩或大量抽提了S型花岗岩物质后的地壳源区不同,西山火山侵入杂岩的I(Sr)(0.71612～0.71823)较高,εNd(-7.0～-8.0)较低,钕模式年龄(1 517～1 600Ma)略小于区域上变质基底和中国东南部中生代花岗岩类的钕模式年龄,显示其直接来源于地壳物质的部分熔融,但可能有少量新生地幔物质的加入。西山铝质A型花岗质火山侵入杂岩是中侏罗世晚期挤压造山作用趋于结束,造山带崩塌,岩石圈强烈伸展减薄、热流值上升的构造背景下形成的造山后花岗质岩石。  相似文献   

Evolution of the late Quaternary San Gregorio Magno tectono‐karstic basin (southern Italy) inferred from geomorphological,tephrostratigraphical and palaeoecological analyses: tectonic implications     

G. Aiello  A. Ascione  D. Barra  R. Munno  P. Petrosino  E. Russo Ermolli  F. Villani 《第四纪科学杂志》2007,22(3):233-245

The Pantano di San Gregorio Magno is a 4.7 km² large tectono‐karstic basin located in the axial belt of the Southern Apennines, an area affected by intense seismicity. The basin was formed in the Middle Pleistocene and is presently undissected. It is filled by lacustrine sediments (clays, silts and pyroclastic sands) passing laterally into alluvial fan deposits. Geomorphological investigations were integrated with tephrostratigraphical, palynological and palaeoecological analyses of a 61 m thick core (not reaching the bedrock). The multiproxy analysis of the S. Gregorio Magno record shows that, over the last 200k yr, the basin hosted a freshwater lake with an oscillating level. Age constraints provided by the tephrostratigraphic record allowed estimation of the sedimentation rate, which varied strongly through time. Evolution of the basin resulted from the complex combination of tectonic subsidence, karst processes and changing amounts of sedimentary inputs. The latter was influenced by allogenic contributions related both to primary and reworked volcanoclastic inputs and was climate‐driven. The overall evidence, which indicates that in the long‐term the accumulation rate substantially counterbalanced the accommodation space created by faulting, suggests that the basin evolution was also modulated by changing subsidence rates. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Mesoscale surface circulation and variability of Southern Indian Ocean derived by combining satellite altimetry and drifter observations   总被引：1，自引：1，他引：0  

BENNY N. Peter  SHENBAKAVALLI Ranjan  MAZLAN Hashim  MOHD Nadzri Re  MOHD Razali Mahmud 《海洋学报(英文版)》2015,34(9):12-22

High resoultion Eulerian mean velocity field has been derived by combining the satellite tracked surface drifter data with satellite altimetry and ocean surface winds. The drifter data used in this study includes Argos and surface drifter data from Global Drifter Program. Maps of Sea Level Anomaly(MSLA) weekly files with a resolution of(1/3)° in both Latitude and Longitude for the period 1993–2012 have been used. The Ekman current is computed using ocean surface mean wind fields from scatterometers onboard ERS 1/2,Quikscat and ASCAT. The derived mean velocity field exhibits the broad flow of Antarctic Circumpolar Current with speeds up to 0.6 m/s.Anomalous field is quite significant in the western part between 20° and 40°E and in the eastern part between 80°E and 100°E with velocity anomaly up to 0.3 m/s. The estimated mean flow pattern well agrees with the dynamic topography derived from in-situ observations. Also,the derived velocity field is consistent with the in-situ ADCP current measurements. Eddy kinetic energy illustrates an increasing trend during 1993–2008 and is in phase coherence with the Southern Annular Mode by three month lag. Periodic modulations are found in the eddy kinetic energy due the low frequency Antarctic Circumpolar Wave propagation.  相似文献   

Learning from the systematic approach to aquaculture zoning in South Australia: A case study of aquaculture (Zones – Lower Eyre Peninsula) Policy 2013     

《Marine Policy》2015

South Australia is among the regions internationally, where there are currently strong drivers for anthropogenic and ecosystem marine planning decisions. Specifically, South Australia, in both State and adjacent Commonwealth Waters, is currently accommodating increasing interests such as oil exploration by multi-national companies in the Great Australian Bight, implementation of recently declared State Marine Parks, an increased public awareness of marine developments, commissioning of a desalinisation plant, government-focused marine science initiatives, long-standing commercial fisheries, a transparent legislative and political stage, and a relatively new aquaculture industry. Amongst this growing diversity in marine-based activities, a dedicated aquaculture legislative framework was created in South Australia with the commencement of the Aquaculture Act 2001 (the Act) to centralise the legislative processes required to underpin aquaculture regulation and administration. This centralisation has helped to create an effective platform to streamline administrative processes, reduce duplication between various government agencies such as planning authorities and environment protection agencies, and ultimately fostered investment in, and growth of, the South Australian aquaculture industry. As such Aquaculture zone policies are a key strategic management tool for sustainable aquaculture development in South Australia into the future. This paper provides a case study (Aquaculture (Zones – Lower Eyre Peninsula) Policy 2013) of the legislated regional marine planning framework for aquaculture development used in South Australia, with a focus on the key functions and processes that may have broader applications.  相似文献   

IMPACT OF SSTA OF SOUTHERN HEMISPHERE ON FLOOD SEASON PRECIPITATION ANOMALIES IN YUNNAN     

杨竹云  杨素雨  严华生  张瑾文 《热带气象学报(英文版)》2015,21(3):255-264

Based on the reanalysis data of monthly mean global SST and wind from the NCEP/NCAR and the observation data of rain seasons in 124 stations of Yunnan province from 1961 to 2006, we applied the analytical methods of correlation analysis and composite analysis and a significance testing method to two sets of samples of average differences. The goal is to investigate into the influence of the Southern Hemispheric (SH) SST on the summer precipitation in Yunnan from January to May so as to identify the key time and marine regions. Physical mechanisms are obtained by analyzing the influence of sea level wind and the key marine regions on the precipitation during Yunnan’s rain season. Results show that there is indeed significant relationship between the SST in SH and summer precipitation in Yunnan. The key areas for influencing the summer precipitation are mainly distributed in a region called “West Wind Drift” in the SH, including the Southeast Indian, southern Australia, west coast of eastern Pacific off Chile, Peru and the southwest Atlantic Magellan. Besides, the most significant marine region is the west coast of Chile and Peru (cold-current areas of the eastern Pacific). Diagnostic analysis results also showed that monsoons in the Bay of Bengal, a cross-equatorial flow in the Indian Ocean near the equator and southwest monsoon in India weaken during the warm phase of the Peruvian cold current in the eastern Pacific. Otherwise, they strengthen.  相似文献   

南大洋淡水强迫对南半球环状模的影响分析   总被引：1，自引：0，他引：1  

马浩  李正泉  冯涛  刘成彦 《气象与环境学报》2015,(3):81-88

南半球环状模是南半球热带外大气环流变异的主导模态,对南半球海洋—大气—海冰耦合系统有重要的影响。冰川融化激发的淡水强迫是南大洋的一种重要外强迫。在历史气候记录中,南大洋淡水通量异常曾引发数次全球性气候异常事件。基于海—气完全耦合模式FOAM,在60°S以南的海洋中施加强度为1.0 Sv的理想化淡水通量异常,分析南半球环状模的响应。结果表明：南大洋淡水通量异常可使局地西风增强,且西风的增强在垂向各个层次上均有体现。西风强度的变化导致对流层中大气斜压性增强,平流层中大气斜压性减弱。此外,淡水强迫使环状模的年际变率振幅显著减弱,而年代际变率开始增强,谱能量的变化具有垂向一致性。海温和海冰等外强迫因子的变化对环状模年代际振幅的增强具有重要意义。  相似文献   

南极涛动异常及其对冬春季北半球大气环流影响的数值模拟试验   总被引：14，自引：0，他引：14       下载免费PDF全文

范可  王会军 《地球物理学报》2007,50(2):397-403

利用IAP9L-AGCM模式考察了模式中与南极涛动异常相关的海温敏感区，发现南半球高纬海温异常能够强迫出南极涛动异常，而赤道东太平洋海温异常与太平洋南美型密切相关.研究了南极涛动异常对冬春季北半球大气环流及亚洲北部气温的影响，结果表明，南极涛动加强，能够引起北半球高纬环流异常和欧亚西风加强，以及亚洲北部地表气温和850 hPa气温显著增温.数值模拟支持了已有的诊断结果，也证实了冬春季节南极涛动异常下两半球高纬间的经向遥相关存在.  相似文献   

The watermass variability and southward shift of the Southern Hemispheremid-depth supergyre     

DUAN Yongliang  HOU Yijun  LIU Hongwei  LIU Yahao 《海洋学报(英文版)》2013,32(11):74-81

The Southern Hemisphere subtropical supergyre at intermediate depths connects all three ocean basins and plays a significant role in responding and conveying the climate-change-related variations in the glob- al ocean. On the basis of the Simple Ocean Data Assimilation/SODA） ocean reanalysis, the thermohaline variability and southward shift of the mid-depth supergyre are demonstrated. The steric height of the sub- surface relative to 1 500 m （400-1 500 m） from the SODA depicts exactly the flow patterns and variability of the oceanic supergyre. During 1958-2007 the water masses in the gyre interiors become cooler/fresher, with the significant exceptions of the Agulhas Current system and Agulhas leakage. The results also exhibit a pronounced strengthening of the inter-basin connection of the supergyre, and the strongest southward shift, by about 2.5° over the whole period, occurs in the central-south Pacific, which is associated with the changes in the basin-scale wind forcing.  相似文献   

Ocean/ice shelf interaction in the southern Weddell Sea: results of a regional numerical helium/neon simulation     

Christian B. Rodehacke  Hartmut H. Hellmer  Oliver Huhn  Aike Beckmann 《Ocean Dynamics》2007,57(1):1-11

Ocean/ice interaction at the base of deep-drafted Antarctic ice shelves modifies the physical properties of inflowing shelf waters to become Ice Shelf Water (ISW). In contrast to the conditions at the atmosphere/ocean interface, the increased hydrostatic pressure at the glacial base causes gases embedded in the ice to dissolve completely after being released by melting. Helium and neon, with an extremely low solubility, are saturated in glacial meltwater by more than 1000%. At the continental slope in front of the large Antarctic caverns, ISW mixes with ambient waters to form different precursors of Antarctic Bottom Water. A regional ocean circulation model, which uses an explicit formulation of the ocean/ice shelf interaction to describe for the first time the input of noble gases to the Southern Ocean, is presented. The results reveal a long-term variability of the basal mass loss solely controlled by the interaction between waters of the continental shelf and the ice shelf cavern. Modeled helium and neon supersaturations from the Filchner–Ronne Ice Shelf front show a “low-pass” filtering of the inflowing signal due to cavern processes. On circumpolar scales, the simulated helium and neon distributions allow us to quantify the ISW contribution to bottom water, which spreads with the coastal current connecting the major formation sites in Ross and Weddell Seas.

Christian B. RodehackeEmail:

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南秦岭钡成矿带重晶石与毒重石成矿特征   总被引：4，自引：1，他引：3  

吴胜华  刘家军  张鼐  柳振江 《现代地质》2010,24(2)

在我国扬子地块北缘南秦岭一带的早古生代硅质岩建造中,存在一大批重晶石矿床和毒重石矿床,构成世界上极为罕见的大型钡成矿带。根据流体包裹体显微测温分析,重晶石流体包裹体均一温度峰值低于毒重石流体包裹体峰值。这些矿床中重晶石的3δ4S值比同期海水3δ4S值高(除去文峪矿区重晶石一个3δ4S值与同期海水3δ4S值接近),表明当时细菌对硫酸盐的还原作用引起了重S的富集。各钡矿床中的毒重石有各自的1δ3C和1δ8O值范围,毒重石中的C来自有机质事件反应。根据热力学计算表明,小于162.42℃的温度有利于形成重晶石矿石;在温度高于162.42℃时,海水中积累充足的CO32-(来自有机事件)有利于形成毒重石矿石。在重晶石矿床形成的晚期,如出现贫Ba2+热液,且海水中积累足够的CO32-和温度高于162.42℃,CO32-可以交代重晶石中的SO42-,形成交代成因的毒重石。  相似文献