第四纪洞庭盆地赤山隆起与安乡凹陷升降运动的沉积记录

通过地表地质调查和钻井资料,对第四纪洞庭盆地南部赤山隆起及其西侧安乡凹陷的沉积和地貌特征进行研究,进而探讨二者的升降过程。赤山隆起为居于洞庭盆地南部的小型抬升断块,主要受东、西边界正断裂所控制,长约18 km,宽4~5 km。隆起内早更新世汨罗组和中更新世新开铺组、白沙井组组成多级阶地。安乡凹陷内充填200~300 m厚的河流和湖泊相沉积,自下而上依次为早更新世华田组、汨罗组,中更新世洞庭湖组,晚更新世坡头组,全新世湖积、冲积等。地貌与沉积特征表明,早更新世—中更新世中期赤山隆起总体表现出抬升期与稳定期交替的脉动式抬升,而安乡凹陷则表现出缓慢与快速沉降交替的幕式沉降特征;前者构造较稳定期和构造抬升期分别对应于后者缓慢沉降期和快速沉降期。中更新世晚期二者因区域构造反转而整体抬升并遭受剥蚀。晚更新世—全新世安乡凹陷在拗陷背景下接受沉积。上述第四纪早期赤山隆起脉动式抬升与安乡凹陷幕式沉降的对应关系,为洞庭盆地与周边隆起的盆—山耦合过程提供了约束,同时暗示盆地断陷活动可能与地幔上隆导致中地壳物质自凹陷向周边迁移有关。     

长江中下游庐江-枞阳火山岩矿集区深部结构与成矿作用

为探测长江中下游成矿带庐江-枞阳白垩纪火山岩盆地和铁、硫矿集区深部构造和地壳结构,探讨成矿深部控制条件,作者完成了穿越火山岩盆地的深反射地震剖面(150km,记录30s)和罗河铁矿区浅层高分辨反射地震剖面(20km),以及平行剖面的大地电磁、高精度重磁剖面,揭示了矿集区全地壳精细结构和电磁结构,同时开展区域构造测量和火山岩年代学研究,获得了新的认识。证实"耳状"的庐-枞火山岩盆地是一个沿北东向罗河断裂向东侧发育的非对称火山盆地,排除了另一半被断在西侧红层之下的判断;罗河断裂是一条切穿MOHO的深断裂,倾向南东,是引导地幔流体和岩浆上涌和喷发的通道,在中地壳形成岩浆房(反射亮斑);鉴别出多层界面,火山岩-侏罗系厚度约4~5km(其中火山岩厚度约3km),三叠系-震旦系变形层底界深度大致18~20km,变质基底组成中下地壳,MOHO平缓向北西倾,深度33~31km;追踪郯-庐断裂带的深部产状,陡立延伸到MOHO,宽约10km。从而揭示了早白垩系(132~127Ma)庐-枞火山岩矿集区深部过程与成矿、控矿作用。     

王水溶样-电感耦合等离子体发射光谱法同时测定铁铜铅锌硫化物矿石中8个元素

建立了王水溶样-电感耦合等离子体发射光谱法同时测定铁、铜、铅、锌硫化物矿中Cu、Pb、Zn、As、Ag、Cd、Hg和Mo等8个元素的分析方法。确定了方法的溶矿及测定条件,用国家一级标准物质GBW07162(多金属贫矿石)和GBW07164(多金属矿石)进行精密度实验,除个别元素外,大多数的元素精密度(RSD,n=11)小于5%,准确度(RE)小于10%。通过一系列硫化物矿石标准物质进行方法验证,检测结果基本都在标准值的误差范围内,符合地质矿产开发的要求。方法简单,同时测定元素较多,线性范围宽,检出限低,尤其有利于硫化物矿石中的亲硫元素As、Ag、Hg的分析,实用性强。     

论构造耦合作用

构造耦合作用是一种普遍存在的地质现象。现今东、西太平洋的构造差异及古太平洋和现今太平洋大陆边缘构造差异与俯冲的洋壳板块性状有关,即:①俯冲角度;②俯冲角度的改变;③俯冲速率;④俯冲速率的改变;⑤俯冲深度;⑥俯冲板块前缘与海沟间的水平距离;⑦俯冲板块在670km上、下地幔界线处的构造形态;⑧俯冲板块的位移及位移方向。这种深部构造活动对浅部构造形成的制约和影响,是活动大陆边缘构造耦合现象的具体表现。中国西北部的盆山耦合现象是大陆内部的构造耦合作用,印度板块与欧亚板块碰撞产生的远距离效应,导致中亚地区产生陆内A型俯冲,A型俯冲是造成盆地消亡、山系形成的重要因素。     

南四湖非法采砂治理对策

介绍了南四湖黄砂资源情况及非法采砂情况,分析了打击非法采砂面临的困境,提出了联合执法常态化,建立执法部门之间的协调机制,召开座谈会推动立法,制定南四湖资源环境保护规划,加大经费投入,加强宣传教育等治理措施。     

湘东南志留纪彭公庙花岗岩体的地质地球化学特征及其构造环境

志留纪彭公庙岩体地处湘东南,岩石类型主要为黑云母花岗闪长岩、黑云母二长花岗岩、二云母二长花岗岩。各岩石单元从早至晚,w(S iO2)总体由低变高,变化在65.30%~73.42%之间;w(K2O)平均为4.34%,w(Na2O+K2O)为6.46%~8.32%,平均为7.09%;w(K2O)/w(Na2O)平均为1.58;岩石富铝,w(A l2O3)平均为14.13%。岩体总体属铁质、强过铝质高钾钙碱性花岗岩。Ba、Nb、Sr、P、Ti相对于原始地幔为负异常,Rb、(Th+U)、(La+Ce)、Nd、(Zr+H f+Sm)、(Y+Yb)等则相对富集。w(ΣREE)平均为221.85×10-6;轻稀土富集,w(La)N/w(Yb)N值平均为8.66;Eu弱亏损,δ(Eu)平均为0.53。ISr值为0.712 30~0.718 31,εSr(t)为110.7~196.1,εNd(t)为-8.0~-8.7,t2DM为1.81~1.87 Ga。上述地球化学特征表明彭公庙岩体为S型花岗岩。在C/MF-A/MF图解中,样品点部分落入基性岩区,部分落入变质碎屑岩区;在岩体氧化物比值的Harker图解中,各样点构成良好的线性关系;在w(La)/w(Sm)-w(La)图解中样品点分布散乱;酸性程度最高的晚期恩垄岩石单元的轻稀土相对富集更为明显;岩石中发育镁铁质岩浆包体等,表明彭公庙岩体具岩浆混合成因。地球化学构造环境判别图解、岩体侵位地质特征以及区域构造演化背景等表明彭公庙岩体形成于后造山构造环境。岩体各岩石单元侵位的先后次序可能与岩浆的粘度密切相关,基性程度相对较高的岩浆向上运移速度更快,因而侵位更早。     

利用地下水动力学解析法计算回采工作面涌水量

在综合分析山东兖州兴隆庄煤矿4326综放工作面井下瞬变电磁探测资料、矿井和相邻工作面水文地质资料的基础上,确定了工作面顶板砂岩含水层的水文地质参数,采用地下水动力学解析法计算工作面涌水量.经验证其计算结果与实际基本相符.     

Microthermometric measurement of fluid inclusions and its constraints on genesis of PGE-polymetallic deposits in Lower Cambrian black rock series, southern China

Systematic microthermometric measurements of fluid inclusions in the PGE-polymetallic deposits hosted in the Lower Cambrian black rock series in southern China were performed, and the results suggest: (1) there exist two types of fluid inclusions. TypeⅠis of NaCl-H2O system with low-medium salinity, and its homogenization temperatures (Th) and salinities are 106.9- 286.4℃ and ( 0.8- 21.8) wt%NaCl eq. respectively; TypeⅡ is of CaCl2-NaCl-H2O system with medium-high salinities, and its homogenization temperatures and salinities range from 120.1℃ to 269.6℃ and ( 11.4- 31.4) wt%NaCl eq., respectively. The typeⅡ fluid inclusions have been discovered for the first time in this kind of deposits; (2) two generations of ore-forming fluids were recognized. Characteristics of fluid inclusions in the PGE-polymetallic ores and carbonate-quartz stockworks in the underlying phosphorites are almost of no difference, they may represent ore-forming fluids at the main metallogenic stage. The peak value of homogenization temperature of those fluid inclusions is about 170℃, while their salinities possess a remarkable bimodal distribution pattern with two peak values of (27-31) wt%NaCl eq. and (4-6) wt%NaCl eq. On the contrary, fluid inclusions in the carbonate-quartz veins in the hanging wall may represent ore-forming fluids at the post-metallogenetic stage. The homogenization temperatures and the peak values of salinities are mostly 130-170℃ and (12-14) wt%NaCl eq., respectively; (3) nobel gas isotopic composition analyses in combination with the microthermometric measurements of fluid inclusions suggest that the ore-forming fluids at the main metallogenetic stage were probably derived from mixing of basinal hot brines with the CaCl2-NaCl-H2O system and seawater with the NaCl-H2O system; (4) in the Early Cambrian, the basinal hot brines were trapped in the Caledonian basins, which were distributed along the southern margin of the Yangtze Craton, and where giant thick sediments were accumulated, and expelled and migrated laterally along the strata because of the pressure caused by overlying sediments. The basinal hot brines absorbed Ni, Mo, V, PGE from the surrounding rocks and were transformed into ore-bearing hydrothermal fluids with the CaCl2-NaCl-H2O system and medium-high salinities, then ascended along faults and mixed with seawater of the NaCl-H2O system, and finally PGE-polymetallic deposits or occurrences were formed in the black rock series.     

桩端持力层加筋作用的特性探讨

运用弹性半空间无限体的明德林解答和浅基础中的分层总和法、桩土间滑动采用刚塑性模型，以某工程试桩资料为例，较详细地分析了桩端持力层加筋作用的特性。并通过工程实例证明本文研究结果是正确的，这对桩基的设计和研究有较大的参考价值。