山东三山岛金矿床流体包裹体特征及其地质意义

三山岛金矿床位于莱州市三山岛—仓上断裂带内,矿石主要为蚀变岩和含金石英脉2种类型。随着胶东金矿床研究的深入和三山岛金矿资源的不断减少,对三山岛金矿床的成矿作用及深部开发前景问题研究具有更重要的意义。针对上述问题,对三山岛金矿床2种类型矿石的成矿流体特征进行对比研究,认为代表成矿早—中期的蚀变岩型矿石形成于中温(均一温度为325～240℃)、低盐度(2.07%～6.88%)、低密度(0.720～0.868g/cm3)、酸碱性不均匀(pH=3.27～10.43)、以氟化物和氯化物为成矿物质载体的还原性流体;代表成矿中—晚期的含金石英脉型矿石形成于中—低温(均一温度为306～160℃)、低盐度(1.05%～9.73%)、低密度(0.739～0.962g/cm3)、碱性(pH=9.25～9.85)、以氯化物和硫化物为成矿物质载体的还原性流体。成矿流体性质的转变反映了成矿流体处于由比较封闭到比较开放的构造环境的转变期,且成矿流体早期以原生岩浆水为主,后期有变质水、大气降水以及海水的参与作用。三山岛金矿成矿深度为2.5～5km,根据目前的开采深度推算其深部还有一定的资源量可供开发。     

新疆南天山库车坳陷区东秋里塔格断褶带构造特征及新活动性

库车坳陷是南天山中段新构造运动异常强烈的地区,内部发育有四排近EW向展布的逆断裂-背斜带,由南天山山前向塔里木方向依次为:山麓逆断裂-背斜带;喀桑托开逆断裂-背斜带;秋里塔格逆断裂-背斜带和亚肯盲逆断裂-背斜带.东秋里塔格背斜属秋里塔格逆断裂-背斜带东段部分,其构造运动尤为强烈.研究表明:东秋里塔格背斜是浅部滑脱面与其南翼逆冲断层共同形成的断层传播-滑脱混生褶皱,背斜南翼的浅层逆冲断层和深层的断坡构造是重要孕震场所.东秋里塔格浅部背斜核部的背冲式断裂和北翼的膝折属于派生的次级构造,断裂的规模、错动量有限.东秋里塔格背斜南翼逆断层最新活动错断Ⅱ级阶地砾石层,其活动年代至少为全新世早期,这次错动在地表留有3～4 km长的古地震破裂形迹,说明断裂具粘滑运动特征.     

东海陆坡及邻近槽底天然气水合物成藏条件分析及前景

在西太平洋边缘海中,东海是唯一没有获得天然气水合物样品的边缘海。利用已有的地震资料、海底温度资料等,从沉积物来源、沉积地层厚度、烃源岩条件、沉积速率、海底温度—压力条件等方面对东海水合物成藏条件进行了分析。认为冲绳海槽沉积物源丰富,沉积厚度大,且发育烃源岩地层。冲绳海槽较高的沉积速率主要分布于冲绳海槽槽底沉积中心,以及西部陆坡连接海底峡谷底部的三角洲区域。根据冲绳海槽实测的海底温度数据,整个冲绳海槽地区600m以深的范围都能够满足水合物发育的温度、压力条件。以温度梯度为30℃/km计算,冲绳海槽中水合物稳定域的最大厚度为650m。冲绳海槽盆地中普遍发育的底辟构造、背斜构造等局部构造,以及网格状断裂系统,为烃类气流体的向上及侧向运移创造了有利条件,成为天然气水合物发育的有利区带。根据已经发现的BSR特征来看,东海地区天然气水合物前景广阔。     

探地雷达在马来西亚某石灰岩工地探测实例

石灰岩地区地质条件比较复杂,进行建筑施工之前了解清楚石灰岩的起伏及岩溶破碎带的分布情况对分析地基的稳定性非常重要.马来西亚某石灰岩工地探地雷达探测实例显示,探测解释结果同钻孔验证结果基本吻合,说明利用探地雷达可以获得关于地基的地质信息,可为建筑设计和施工提供参考依据.     

鄂尔多斯盆地南部晚三叠世沉降与沉积中心研究

从古地貌恢复的角度出发,依据残留厚度和补偿厚度印模法原理,恢复了鄂尔多斯盆地晚三叠世早期古地层厚度,从而确定了沉降中心;选取粒度矩法平均值这一参数,对同井位同层位的粒度值求平均值,将所得值投放平面图,获得粒度均值平面等值线图,湖盆中细粒碎屑物质的聚集区反映了古水流的汇合区,指示沉积中心。研究结果表明,鄂尔多斯盆地晚三叠世早期沉降中心位于马家滩-白豹-宜君一线,西南部镇原-崇信一线存在局部沉降区,盆地的地层厚度变化较大,说明晚三叠世差异沉降作用明显;而沉积中心主要位于正宁-合水-姬塬-吴起-志丹-太白-黄陵-黄龙一线围成的区域,由西北向东南延展,并以北西-南东为轴向两侧迁移,长10至长7沉积期湖岸线的变化,反映了受构造沉降速率控制,湖盆的沉积中心不断扩大,长7沉积期湖盆面积最大。     

Distribution of Palygorskite in the Lingtai Profile of Chinese Loess Plateau: Its Paleoclimatic Implications

Palygorskite is a typical indicator mineral of the arid and strong evaporation environment. Distribution of palygorskite in loess-red clay sequences may act as an important indicator for reconstruction of the paleoenvironment and paleoclimate. In this paper, field emission scanning electron microscope and high-resolution transmission electron microscope observations on the red clay-loess-paleosol of the Renjiapo profile at Lingtai, Gansu Province indicate that palygorskite occurs widely in red clay sequences formed before 3.6 Ma, but no occurrence has been found in eolian sediments since 3.2 Ma. Micromorphological features and microstructure of palygorskite show that it is an autogenic mineral formed during pedogenesis, and transformed from iilite-montmorilionite under the pore water action. In the Lingtai profile, the disappearance horizon of palygorskite is consistent with those of increasing magnetic susceptibility, dust flux and depositional rate. The distribution of palygorskite in the profile indicates that the interval of around 3.6 Ma was an important transformation period of the East Asian paleomonsoon, when changes took place in the East Asia paleoclimate pattern, i.e. a high-frequency strong fluctuation alternative evolution of the environment. Therefore, palygorskite is a key indicator mineral of the East Asian paleomonsoon evolution of that time.     

Multifractal Analysis of Element Distribution in Skarn-type Deposits in the Shizishan Orefield, Tongling Area, Anhui Province, China

A series of element concentrations sampled from four drill cores with a length about 1000 m into different skarn-type deposits were selected from the Shizishan orefield, central Tongling, southeastern part of Anhui Province. Using the multifractal method, the distribution and migration characteristics of the major and trace elements are analyzed. The multifractal spectrum of the major elements is left-skewed, whereas the spectrum of the trace elements is right-skewed, which shows that in the process of skarn formation, the trace elements were enriched only locally, and major elements transported within a much larger range. The correlation coefficients of the multifractal parameters Aa （width of the multifractal spectrum） of the four drill cores are relatively low, but the correlation coefficients of the multifractal parameters R （spectrum symmetry parameter） and Af are relatively higher, indicating that although the non-homogeneous intensity of the distribution of elements is inconsistent, their spatial accumulation patterns are almost the same during the ore-forming process. The statistics of the mnltifractal parameters of various elements in the different locations show that the ore-forming processes and element migration pattern in the Shizishan orefield are consistent, and that the migrations of trace elements and major elements exhibit some differences.     

中国金矿床(Ⅰ):成矿理论研究新进展

针对中国近年来金矿床学领域研究工作,综合讨论了金矿床成矿学理论研究方面的主要进展。它们集中体现在①大型一超大型金矿床;②区域成矿学与成矿系统;③造山带成矿与造山型金矿：从俯冲（增生）造山到碰撞造山成矿的显著发展;④成矿系列、成矿谱系到成矿体系研究;⑤热点、地幔柱及其多级演化：从边缘成矿到板内成矿;⑥成矿时代：从模糊到精确;⑦现代金矿成矿的实时模型;⑧从板块构造演化、超越板块构造到成矿地球动力学等8个方面。     

苏锡常地区地面沉降风险评价管理模型研究初探

平原区超采地下水引发的地面沉降地质灾害已成为影响这些地区经济可持续发展的重要制约因素,如何从收益、成本、风险三个方面为决策者提供制定地面沉降相关防治措施的综合支持,实现灾害防治从被动应对向主动防御转变,是地面沉降防治研究领域的新课题。在综合考虑苏锡常地区技术、经济、人类活动等因素基础上,从地面沉降总体风险和地区差异水平出发,提出构建地面沉降风险评价模型及决策支持系统的初步研究思路和方法,为实现地面沉降防治的科学化决策管理进行了探索。     

甘肃东沟金矿床地质矿化特征及找矿方向

东沟构造蚀变岩-石英脉型金矿床,位于关子镇-元家坪和娘娘坝-舒家坝两条韧性剪切带与天子山和磨扇沟花岗岩体的夹持区,金矿化严格受其次级近EW向断裂控制,后期断裂构造对矿体具一定破坏作用。矿石类型地表以构造蚀变岩型为主,向深部过渡为石英脉型,褐铁矿、黄铁矿、毒砂是主要载金矿物。围岩蚀变以硅化、褐铁矿化、黄铁矿化、绢云母化为特征。中基性火山岩、韧脆性断裂构造、中酸性岩浆侵入“三位一体”是控制矿床形成的基本条件,近EW向断裂蚀变带及延伸部位是找矿有利地段。