Sedimentary environment and development controls of the hydrocarbon source beds:Middle and Upper Proterozoic in northern North China

Problem on development control of marine source bed hold in Chinese petroleum industry progression. The Hongshuizhuang Formation,Tieling Formation and Xiamaling Formation in the Middle and Upper Proterozoic are important hydrocarbon source beds in northern North China, and investigation of their sedimentary environments and the controls has great significance for petroleum exploration in North China. Based on sedimentology (sequence stratigraphy), palaeoecology, sedimentary geochemistry, and sedimentary palaeogeography, their development pattern is discussed. All these studies indicate that the development controls of the hydrocarbon source beds include a favorite palaeogeographic location, exceeding propagation of biomes in low and middle latitudes, anoxic environments, enrichment of phosphorus element and the adsorption of clay minerals during the preservation of organic matter in the marine carbonates.     

浙江花岗岩类地球化学与地壳演化——Ⅱ.元古宙花岗岩类

浙江元古宙花岗岩类包括神功期（1．8－1．9Ga）和晋宁晚期（0．6—0．9Ga）。研究了浙江元古宙花岗岩类的主元素、微量元素、稀土元素和Rb、Sr同位素组成特征及岩石成因，探讨了浙江地壳的演化。浙江地壳形成于太古亩和元古宙，地壳增生的时期为2．6－2．7、0．8-1．1和0.1－0.12Ga。随时间演化浙江地壳组成有变化，但分异演化不明显。沿江-绍断裂分布的晋宁晚期慢源和壳幔混合中酸性岩是普宁期俯冲碰撞的证据。加里乐和印支期是两次规模不大的构造运动。     

中国西部元古代蓝片岩带——世界上保存最好的前寒武纪蓝片岩

阿克苏附近所发现的元古界阿克苏群为一完整的蓝片岩-绿片岩系列,我们通过野外调查肯定了这一认识,并认为它是高压-温相的变质块体,长40km,宽约2.5km.该变质岩由强烈片理化的绿泥石-黑硬绿泥石石墨片岩、黑硬绿泥石-多硅白云母片岩、绿片岩、蓝片岩及少量石英岩、变铁质岩组成.原岩包活泥质岩、砂岩、基性玻屑凝灰岩、块状熔岩、枕状熔岩及少量深海沉积物.蓝片岩的矿物组合:青铝闪石-绿帘石-绿泥石-钠长石-石英-阳起石.阿克苏群为世界上真正的前震旦纪蓝片岩之一,其变质年龄至少有800Ma.     

颗石藻与海洋、环境关系之探讨

笔者在20年的研究中相继发现,自中元古代和古生代以来海相钙质超微浮游生物－颗石藻的新属种达180余种,通过对颗石藻在海洋中分布状态与固碳特征的研究,证明颗石藻乃是海洋中重要的基础生产者,它和海洋碳酸盐及相关生物存在着密切的关系,其能借助光合作用,吸收海水中的CO2,而释放出氧气．对减少全球温室效应与保护地球生态环境平衡,有相当重要的贡献。     

辽南早元古宙变质热液型金矿床成矿机理探讨

辽南早元古宙辽河群变质岩系中的金矿床为变质热液成因金矿床,矿床的形成与吕梁期变质变形作用关系密切。金矿化带的展布与金矿体的产出受韧性剪切带控制。剪切带内岩石具有明显的动态性组构特征,直接赋矿围岩为辽河群盖县组糜棱岩化千枚岩、变砂岩及云母石英糜棱岩等。韧性剪切带为含矿流体的运移提供通道。作者定义这类金矿床为变质热液型含金剪切带金矿床。     

An interpretation of the structure of the Blatherskite Nappe,Alice springs,Northern Territory

The basal unit of the Amadeus Basin sequence is the Heavitree Quartzite, and this formation usually forms a single east‐west ridge along the northern side of the MacDonnell Ranges. However, at Alice Springs there are two such ridges. Basement rocks crop out on the northern side of each ridge, and dolomite and shale of the Bitter Springs Formation crop out on their southern sides. The northern outcrop of dolomite and shale is tightly folded, and is separated from the southern outcrop of basement by a major fault. The bedding of the sediments, the axial plane of the fold, and the fault all dip south at about 45°. Inverted facings on parasitic folds indicate that the northern outcrop of quartzite and dolomite plus shale is an antiform in inverted rocks. Hence the southern outcrop of basement and quartzite is synformal, and is interpreted as the frontal part of a fold nappe. The nappe started as a recumbent anticline whose middle limb of quartzite sheared out as the anticline travelled several kilometres southwards relative to the dolomite and shale below, which formed a tight recumbent syncline. Later monoclinal uplift of the northern half of the area tilted the nappe into its present south‐dipping attitude, thus converting the recumbent anticline into a synform and the recumbent syncline into an antiform.     

Crustal contaminants in the Permian Oslo Rift, South Norway: constraints from Precambrian geochemistry

During the late Paleozoic Oslo rifting event, the SW part of the Baltic Shield was penetrated by mantle-derived magmas from a depleted lithospheric or sublithospheric source. Along the way to their final emplacement, these magmas may have interacted with a heterogeneous continental crust, consisting of a mosaic of continental terranes, each with its unique composition and internal crustal history. Information on radiogenic isotope ratios and trace element distributions in the Precambrian terranes surrounding the rift can be used to define characteristic crustal components. These components may be used as endmembers in petrogenetic modelling of the Oslo Rift magmatic system. Based on available data, six endmember components can be identified, and (semi) quantitatively characterized in terms of Sr, Nd and Pb isotopes and selected trace elements. Data on the distribution of rock-types along the rift flanks allow estimates to be made of the relative importance of the components in different parts of the rift. Combining these data with petrological information may allow a realistic understanding of crust–magma interaction in the Oslo Rift magmatic system.     

Regional stress and structure in relation to brown coal open cuts of the Latrobe Valley,Victoria

An interpretation of the origins of folds and joints, which affect the Tertiary Brown Coal Measures of the Latrobe Valley, leads to the proposal that the geological structures have been formed under a regional Late Tertiary NNW‐SSE compressive stress. Considerations of the pattern of measured in situ stresses and of interpreted stresses, derived from earth movements around open cuts and from earthquakes, indicate that a regional NNW‐SSE compressive stress is still in existence in the SE part of Australia at the present time.

It is proposed that the consistencies in the stress orientations reflect consistencies in the Late Tertiary to Recent global movements of the Australian plate.     

国际新元古代年代地层学研究进展与发展趋势

国际地层委员会末元古系分会1989年正式成立以来,经过各国地层古生物学家近十五年的努力,国际末前寒武纪年代地层学研究已取得很大进展.全球末元古系的正式名称--埃迪卡拉系(Ediacaran)以及埃迪卡拉系的底界层型已经国际地科联批准,在国际地层委员会2004年版"国际地层表"中被正式应用(Gradstein et al.,2004).本文综合近年来国际地层委员会末元古系分会有关文件和部分委员的有关建议,对国际新元古代年代地层学研究的进展与未来发展动向作一概要介绍,以期引起国内晚前寒武纪地层古生物学者的广泛关注.     

内蒙古西北部宝音图群Sm—Nd和Rb—Sr地质年代学研究

内蒙古西北部的宝音图群由角闪岩相的变质地层组成。该群中斜长角闪片岩的Sm-Nd全岩等时线年龄为2485±128Ma,可代表宝音图群的形成年龄。等时线的ε_(Nd)(t)值为2.73±2.81,说明岩浆来源于亏损的地幔源区。相同样品的Rb-Sr全岩等时线年龄为623±36Ma,显然反映后期Rb-Sr体系重新均一化的强烈影响,因此该年龄被解释为变质年龄。上述结果表明宝音图群形成于古元古代早期,应属华北板块北缘已知的最古老岩石地层单位,并保留了新元古代末期构造—变质事件的记录。这些认识有助于查明华北板块北缘元古宙构造演化的历史。