Metallogenic epoch and genesis of the gold deposits in Jiaodong Peninsula, Eastern China: a regional review

Gold deposits are characterized by multi-sources, superimposition, large scale and temporal-spatial concentration in Jiaodong Peninsula, Eastern China. In this paper, we review the history and the development of the study on metallogenic chronology and genesis of gold deposits, summarize the main features of superimposed metallogenesis, provide evidence of the Mesozoic complex metallogenic system, and point out some problems for further research of Jiaodong gold deposit cluster from a regional view. Although gold deposits are different in genetic types, ore-forming materials and geological settings, our research indicates that the accumulation and emplacement of the ore-forming materials are temporally-spatially concentrated on a large scale, and the main metallogenic epoch of Jiaodong gold deposits was concentrated in Mesozoic. Metallogenic chronology and geological-geochemical data indicate that there are two periods of gold mineralizations occurred in 130?110 Ma and 90?80 Ma respectively in Jiaodong ore cluster. The gold deposit cluster results from the superimposition of the polygenetic mineralization, and further study is needed to investigate the formation and evolution of the Mesozoic complex metallogenic system.     

韧性剪切带中金成矿地质构造解析方法及找矿预测——以卡拉麦里大断裂带金矿为例

韧性剪切带是地壳中深层次呈带状展布的高应变的韧性断层.韧性剪切带型金矿是一种非常重要的金矿床类型.以卡拉麦里断裂带附近发现的与韧性剪切带型相关的金矿床(金矿点)为研究对象,解剖了韧性剪切带的成矿特征研究,主要从剪切带的构造成因机制、组构特征、剪切带的变形与成矿的关系、金矿与剪切带的关系、成矿模式与成矿预测做了一个深入的分析.大型深剪切断裂应变特征和构造演化控制着金的成矿作用,成矿流体具有多源性,构造叠加和区域构造转换在剪切带长期演化过程中,使得成矿作用具有多期性和复杂性,多种有利累加效应使得成矿作用规模不断提高,从而形成大型剪切金矿带或金矿集中区.     

中国南部NP坳陷的构造圈闭预测

NP坳陷是两套沉积构造层叠合在一起的断陷盆地,是中国南方油气勘探开发的潜力区块;但对坳陷内圈闭认识尚有不足。针对该问题,从地震角度来出发,以地质认识为指导,以岩-电-震关系为主线,对研究区开展二维精细构造解释研究,确立各标志层的地震波组特征,划分上下两套构造层。在此基础上,结合速度分析结果,落实研究区构造形态,预测研究区的构造圈闭分布;并结合钻井资料对预测结果进行评价。根据闭合幅度和圈闭面积等要素将预测圈闭分为3类。     

断层附近反牵引现象的研究

断层附近的反牵引现象是正确判断断层性质，准确寻找断失煤层的一项非常重要的干扰因素，笔者认为，一期构造力形成的正确层国的反牵引褶曲与递断层上升盘牵引褶曲在形态上的区别是，前者是沿断面向下滑的，褶曲较开阔，不形成岩层倒转；后者除断层倾向岩层倾向相反时外，是沿断层面向上推的，褶曲较紧闭，且经常形成岩层倒转，两期构造力复合形成的正断层的反牵引现象，前期由挤压力形成递断层附近的牵引褶曲；后期由拉伸力使两盘沿断面产生相对的升降，断层落差后期大于前期。     

Discussion on marine source rocks thermal evolvement patterns in the Tarim Basin and Sichuan Basin,west China

Taking marine source rocks of lower Paleozoic in the Tarim Basin and Paleozoic ones in the Sichuan Basin as examples, their sedimentation process could be classified into four styles: continuous subsidence with deep sedimentation in early stage, continuous subsidence with deep sedimentation in later stage, that deeply buried-uplift-shallowly buried, and that shallowly buried-uplift-deeply buried. Unlike that in East China, the marine source rocks evolvement patterns did not accord with sedimentation styles one by one in superimposed basins in west China. Taking local geothermal field into account, four types of source rock evolvement patterns were built: that evolved fast in early stage, evolved fast in middle stage, evolved continuously and evolved in multistage. Among them, the 1st pattern contributed little to the present industrial oil pools directly, but paleo-oil reservoirs and gases cracked from crude oils were main exploration targets. Although some gases were found in the 2nd pattern, the scale was not big enough. For the 3rd and 4th patterns, the hydrocarbon potential depended on organic matters maturity in early stage. For relatively low mature rocks, it was possible to generate some oils in later stage; otherwise the main products were gases. Paleo-oil reservoirs remained fairly well in the Sichuan Basin, and most source rocks underwent kerogen-oil-gas processes, which was useful reference to gas exploration in the Tarim Basin.     

V－△型构造

李四光教授在研究了东亚构造后于１９２９年首次提出了这一构造型式。１９７９年，笔者参加塔里木石油遥感调查，在进行陆地卫星图象解释时发现并经过航空目．测和地面检查验证，证实了这是一例发育完整并已进入老年期的、尚属中小型规模的构造形式。     

Z字型叠加褶皱

在东秦岭前寒武系变质岩中,发育了许多Z字型叠加褶皱。它们是由近直立的片麻岩和长英质脉形成的。不同于兰姆赛分类中的叠加褶皱。本文主要讨论它的形成条件、形态特征和叠加样式。     

砂垫层底面应力分布规律的理论分析

对换填法中关于砂垫层厚度的设计理论作了概括介绍 ,通过对土颗粒模型的分析 ,指出砂垫层底面附加应力为均匀分布和梯形分布两种假定的片面性 ,提出新的观点 :砂垫层底面附加应力的分布形状应根据垫层宽高比确定。当宽高比无限大时近似地认为均匀分布 ;宽高比等于或接近 1时 ,呈梯形分布 ;随着宽高比的逐渐减小 ,分布形状逐步过渡到三角形     

四川盆地纵向结构及原型盆地叠合特征

位于扬子克拉通西部的四川盆地在前震旦纪基底形成之后经历了多旋回构造演化,长期以来对其在不同地质历史时期的构造动力学性质、盆地类型存在争议;而理清不同时期盆地类型及其叠合特征对于上扬子克拉通盖层演化及油气勘探具有重要意义。作者利用穿过盆地的北西-南东向区域地震反射大剖面,结合钻井、野外地质、区域地质资料,对四川盆地的构造-沉积演化进行剖析,识别出5个区域不整合面,划分出5个盖层构造层,认为在纵向上形成了海相克拉通裂陷盆地(Z-S)、海相克拉通拗陷盆地(P_1l-T_2l)、海陆交互相断陷盆地(T_3x^1-T_3x^3)、陆相拗陷盆地(T_3x^4-J)、前陆盆地(K-Q)等原型盆地的有序叠合。     

塔北喀拉玉尔滚断裂系构造特征及地质意义

喀拉玉尔滚断裂系位于塔里木盆地北部,是塔北系列北西向展布的断裂之一。为了研究喀拉玉尔滚断裂系性质以及对塔北构造格局的影响,通过野外考察以及地震剖面解释,得出喀拉玉尔滚断裂为一条北西向右旋走滑断裂,受挤压-剪切作用,伴生北喀、中喀和南喀3个雁列褶皱以及次级断裂,为典型走滑断裂展布形态。喀拉玉尔滚断裂带由古生界北西向构造带继承演化而来,曾经历古生代强烈挤压构造运动、中生代平静沉积、新生代斜冲运动3期构造作用,形成了现今地表构造样式。喀拉玉尔滚断裂带处在乌什-温宿构造单元和库车-塔北构造单元之间,对两侧变形、差异压缩起到调节作用。喀拉玉尔滚走滑断裂及其伴生构造的发育可能对油气的运移和聚集产生有利条件。