巴布亚新几内亚利希尔岛拉多拉姆(Ladolam)金矿矿床地质特征及找矿标志     

陈丹丹 《地质与勘探》2017,53(1):187-197

巴布亚新几内亚利希尔岛拉多拉姆金矿处于太平洋板块与印澳板块的板块边界部位,为西南太平洋地区最大的碱性侵入岩有关的低硫型浅成低温热液型金矿。矿床赋存在Luise火山内,成矿与更新世碱性二长闪长岩侵入体有关,该岩体形成于俯冲带环境下被流体交代的上地幔的部分熔融。矿床的矿化可分为三个阶段,在岩体侵入后形成斑岩铜矿化,并在之后逐渐过渡为浅成低温热液型金矿化。该类矿床在成矿过程和矿体的分布明显受到区域性构造、蚀变带和成矿有关角砾岩等成矿结构面的控制,在找矿标志上具有特定的物化探和地质特征,具有较好的找矿远景。  相似文献   

应用ICP-MS研究黔西南地区构造蚀变体稀土元素地球化学特征   总被引：5，自引：2，他引：3  

赵平  李爱民  刘建中  夏勇  严春杰  王泽鹏  杨刚  陈菊 《岩矿测试》2017,36(1):89-96

构造蚀变体(SBT)是沉积作用、构造作用和热液蚀变的综合产物。SBT作为黔西南地区金、锑、萤石等矿产的重要就位空间,金锑矿成矿与其密切相关。近年在黔西南地区发现了丰富的金资源量,关键在于SBT体系的提出及与之为核心的成矿模式的建立和应用。本文应用电感耦合等离子体质谱法(ICP-MS)分析了黔西南台地相区典型矿床的SBT样品,揭示稀土元素的地球化学特征。结果表明,不同矿区SBT的ΣREE=49.55×10~(-6)~271.72×10~(-6),含量变化较大,LREE/HREE=5.62~13.59,轻重稀土分馏明显,轻稀土富集;SBT对北美页岩和CI球粒陨石标准化配分模式图均表现为轻稀土富集的右倾型、"四分组"效应明显、强烈热液作用,为同一体系的产物;大厂至戈塘一线显示高的正铕异常,推测有两个方向含矿热液在此汇聚。本文系统对比了黔西南地区SBT稀土元素地球化学特征,反映该区成矿流体来源及演化,为本区微细浸染型金矿的成矿预测提供了依据。  相似文献   

Geochemical characterization and methane adsorption capacity of overmature organic-rich Lower Cambrian shales in northeast Guizhou region,southwest China     

《Marine and Petroleum Geology》2017

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Review of marine recreational fisheries regulations in Argentina     

《Marine Policy》2017

The effects of recreational fishing on marine stocks and ecosystems have raised global concern in recent years. In Argentina, Southwest Atlantic, angling, netting and spearfishing of coastal bony fishes, sharks, rays and chimaeras are very popular pastime activities with more than 50 years of history. Despite the perceived traditional and economic relevance of these activities in the country, marine recreational fisheries were largely unregulated, and no official fisheries monitoring programs at the national level have been ever put in place. Except for a few particular systems for which some catch-and-effort data were collected by research institutions and non-governmental organizations, no comprehensive surveys aimed at describing the ecological, social or economic aspects of these fisheries have been made. Here, an updated review of the regulations in place for marine recreational fisheries along the Argentine coastline is presented. Of the five coastal provinces encompassing ca. 8400 km and about 20 latitude degrees (~36°S to 55°S) of coastline, only Buenos Aires province has a thorough legislation for its whole territory, which includes 15 protected areas. In the remaining provinces, the regulations for marine recreational fisheries are limited to a few protected areas (seven out of 37 coastal areas under provincial, national or shared jurisdiction). This lack of legislation encourages alleged recreational fishers to develop small-scale commercial fishing operations that are neither controlled nor monitored as such, contributing to the overexploitation of some key coastal stocks.  相似文献   

夏季北大西洋三极型海温异常与中国西南地区气温年际变化的联系     

于怡秋  李忠贤  杨宝钢  魏麟骁  陈晨 《大气科学学报》2022,45(5):745-754

利用1951—2016年Hadley中心海温资料、NCEP/NCAR再分析资料和全国160站气温资料，研究了夏季北大西洋三极型海温异常与中国气温年际变化的联系及可能机制。结果表明，夏季北大西洋三极型海温异常与同期中国西南地区气温年际变化存在显著的负相关关系。夏季北大西洋“-+-”三极型海温异常激发的北半球中高纬欧亚遥相关波列，引起贝加尔湖地区位势高度升高，产生反气旋性环流异常，并引起东亚地区位势高度降低，产生气旋性环流异常。西南地区在对流层中下层位于贝加尔湖异常反气旋性环流的东部和东亚异常气旋性环流的西部，在两者的共同作用下，受异常偏北气流影响，有利于冷空气南下和堆积。与此同时，对流层高层的东亚副热带西风急流位置偏南，西南地区位于急流南侧的异常上升气流中。此种环流形势配置导致中国西南地区气温降低，反之亦然。  相似文献   

自20世纪90年代中后期夏季巴伦支海海冰与秋季中国西南地区干旱的联系加强          下载免费PDF全文

宦杜斌  范可  徐志清 《大气科学学报》2022,45(2):167-178

研究夏季7—8月巴伦支海海冰和秋季9—11月中国西南地区干旱的年际变化的联系,并探讨了其可能机制.结果表明:1979—1997年夏季巴伦支海海冰和秋季中国西南地区干旱在年际尺度上相关不显著,但到1998—2019年,海冰和干旱指数的相关系数增长至-0.69,置信水平达到99％.当夏季7—8月巴伦支海海冰增多时,有利于秋...  相似文献   

Moisture Sources and Their Contributions to Summer Precipitation in the East of Southwest China          下载免费PDF全文

李永华  黄丁安  卢楚翰  向波  周杰  何卷雄 《热带气象学报(英文版)》2023,29(2):153-167

Complex topography, special geographical location and sea-land-air interactions lead to high interannual variability of summer precipitation in the east of Southwest China (ESWC). However, the contributions, influencing factors and mechanisms of remote and local evaporation remain to be further investigated. Using clustering analysis and Hybrid Single-Particle Lagrangian Integrated Trajectory version 5 model, we analyze the contributions of remote moisture transport and local evaporation to summer precipitation in the ESWC and their causes. There are mainly five remote moisture channels in the ESWC, namely the Arabian Sea channel, Bay of Bengal channel, western Pacific channel, Northwest channel 1 and Northwest channel 2. Among the five channels, the western Pacific channel has the largest number of trajectories, while the Bay of Bengal channel has the largest contribution rate of specific humidity (33.33%) and moisture flux (33.14%). The amount of regional average precipitation is close to that of the precipitation caused by remote moisture transport, and both are considerably greater than the rainfall amount caused by local evaporation. However, on interannual time scales, precipitation recirculation rates are negatively correlated to regional average precipitation and precipitation caused by remote moisture transport but are consistent with that caused by local evaporation. An apparent "+ ? +" wave train can be found on the height anomaly field in East Asia, and the sea surface temperature anomalies are positive in the equatorial Middle-East Pacific, the South China Sea, the Bay of Bengal and the Arabian Sea. These phenomena cause southwest-northeast moisture transport with strong updrafts, thereby resulting in more precipitation in the ESWC.  相似文献   

东亚和南亚季风协同作用对西南地区夏季降水的影响   总被引：1，自引：0，他引：1  

王映思  肖天贵  董雪峰  李勇  赵平 《气象学报》2021,79(4):541-557

为探究东亚夏季风(EASM,East?Asian?summer?monsoon)和南亚夏季风(SASM,South?Asian?summer?monsoon)相互作用及其强弱变化对西南地区夏季降水的影响,利用1979—2019年西南地区161站逐日降水观测资料和ERA-5提供的1979—2019年全球再分析资料,通过对...  相似文献