雅鲁藏布大峡谷地质成因

文中总结了雅鲁藏布大峡谷科学探险考察中获得投奔 石学和构造地质学认识与区域上已经取得的多学科成果,论述了牙鲁藏布大峡谷得以形成的根本原因是该地区深部存在着地幔上涌体,雅鲁藏布大峡谷和大另弯的形成是地幔上涌体作用于岩石圈和地表的效应。地幔上涌体的确认揭开了该地区的特有的生物学,气候特征等方面的奥秘,雅鲁藏布大峡谷及其周缘地区是大陆动力学研究,壳－幔动力学,地球系统中各圈层间耦合作用及大陆块体运动学研     

Overwash processes along a gravel beach in south-east Ireland

Recent overwashing, and to a more limited extent overtopping, has occurred on a gravel-dominated beach just west of Carnsore Point in south-east Ireland. At relatively low points swash excursions have breached the duneline and extensive gravel fans have formed on landward-facing slopes. Also, at interbreach positions, swash ramps have been built-up in front of previously eroding dune cliffs, allowing overtopping at heights of up to 5 m above MHWOST, spreading a veneer of sediment over the adjacent dune ridge. In both cases events appear to be preceded by erosion and backbeach sand and gravel deposition. Stratigraphic, textural and fabric analyses assist in identifying environmental conditions that prevailed during overwash throat and fan, and overtopping ramp, sedimentation.     

The Quebradagrande Complex: A Lower Cretaceous ensialic marginal basin in the Central Cordillera of the Colombian Andes

The Quebradagrande Complex of Western Colombia consists of volcanic and Albian–Aptian sedimentary rocks of oceanic affinity and outcrops in a highly deformed zone where spatial relationships are difficult to unravel. Berriasian–Aptian sediments that display continental to shallow marine sedimentary facies and mafic and ultramafic plutonic rocks are associated with the Quebradagrande Complex. Geochemically, the basalts and andesites of the Quebradagrande Complex mostly display calc-alkaline affinities, are enriched in large-ion lithophile elements relative to high field strength elements, and thus are typical of volcanic rocks generated in supra-subduction zone mantle wedges. The Quebradagrande Complex parallels the western margin of the Colombian Andes’ Central Cordillera, forming a narrow, discontinuous strip fault-bounded on both sides by metamorphic rocks. The age of the metamorphic rocks east of the Quebradagrande Complex is well established as Neoproterozoic. However, the age of the metamorphics to the west – the Arquía Complex – is poorly constrained; they may have formed during either the Neoproterozoic or Lower Cretaceous. A Neoproterozoic age for the Arquía Complex is favored by both its close proximity to sedimentary rocks mapped as Paleozoic and its intrusion by Triassic plutons. Thus, the Quebradagrande Complex could represent an intracratonic marginal basin produced by spreading-subsidence, where the progressive thinning of the lithosphere generated gradually deeper sedimentary environments, eventually resulting in the generation of oceanic crust. This phenomenon was common in the Peruvian and Chilean Andes during the Uppermost Jurassic and Lower Cretaceous. The marginal basin was trapped during the collision of the Caribbean–Colombian Cretaceous oceanic plateau, which accreted west of the Arquía Complex in the Early Eocene. Differences in the geochemical characteristics of basalts of the oceanic plateau and those of the Quebradagrande Complex indicate these units were generated in very different tectonic settings.     

鄂北大洪山地区“花山群”的解体

岩性—构造填图结果表明,大洪山区的原“花山群”实际上包含３套不同时代、不同环境的物质建造,应予以解体。其中襄广断裂带内分布的以基性火山岩为主的一套岩系是构造侵位的蛇绿混杂岩,称之为花山蛇绿混杂岩;大洪山以西的耿集—板桥火山—沉积岩系,是南秦岭随县群的构造岩块;剔除这两者之后的碎屑沉积岩系定为真正意义的花山群,沉积时代为晚元古代。     

新疆库鲁克塔格地区辛格尔变质核杂岩特征

辛格尔一带的前震旦纪古老变质岩系为一系列的变质核杂岩。其内核由早—中太古代古陆核组成 ,外核为晚太古代、古元古代、中元古代、新元古代早期变质岩系构成的多层次构造增生楔 ,并有多期剥离断层配套。新元古宙代晚期震旦系为盖层。它是地壳多期伸缩构造的产物。变质核杂岩体是一个有利于成矿的构造体系。辛格尔变质核杂岩构造是一个对有色和贵金属等矿产成矿的有利构造     

PRELIMINARY STUDY ON THE OPHIOLITIC MELANGE IN THE YALU TSANGPU GRAND CANYON AREA

PRELIMINARY STUDY ON THE OPHIOLITIC MELANGE IN THE YALU TSANGPU GRAND CANYON AREA     

蛇绿岩及蛇绿岩构造侵位

已有研究实例阐明了蛇绿岩产出的构造环境及构造侵位机制的多样性 ,其中发育完整的蛇绿岩套具有与现代大洋岩石圈剖面相似的四层结构模式 ,它们形成于洋中脊扩张构造环境。由于构造运动使蛇绿岩套肢解 ,构造侵位于大陆造山带缝合线地带 ,沿断裂构造以构造岩片和构造混杂岩产出。蛇绿岩提供了洋壳形成和破坏的重要证据 ,蛇绿岩带或古缝合线是确定造山带中古洋盆存在及陆块边界的直接标志     

三氯乙烯在模拟有机质-矿质复合体中的吸附行为研究

土壤中有机质与无机矿物长期共存,其存在形式发生着变化。本文利用批实验的方法对三氯乙烯的吸附行为进行模拟研究,结果表明,土壤中有机质与无机矿物是以有机质-矿质复合体形式存在的,有机质与无机矿物的相互作用影响复合体的吸附性能,与有机质、无机矿物单体相比,复合体Kd、Koc明显发生变化;并提出了有机质-矿质复合体模型。     

新疆中天山干沟一带蛇绿混杂岩和志留纪前陆盆地的发现及其意义

托克逊县干沟一带出露有早古生代蛇绿混杂岩和志留纪前陆盆地沉积。其时空配置表明,新疆中天山北缘早古生代大洋在奥陶纪曾发生大规模的向北消减,志留纪因前陆和岛弧的碰撞而形成前陆盆地,充填序列揭示了碰撞造山作用过程。对碎屑岩中陆源锆石同位素测年表明其最新物源的年龄不小于461Ma。而侵入该前陆盆地碎屑岩的花岗闪长岩中火成锆石的同位素测年数据为(386.1±4.1)Ma,限定了前陆盆地的上限。前陆盆地的终结标志着碰撞造山作用的结束。     

中亚蛇绿岩带研究进展及区域构造连接

中亚地区分布着数十条不同时代和不同性南的蛇绿岩带,这些形成于早古生代或新元古代的蛇绿岩带由于受后期构造变动的强破坏,只在极少数地点保存良好。尽管出露分散,确定其时代和性质有一定困难,但其仍具极其重要的构造单元划分、对比和连接意义。在对比和讨论蛇绿岩带的连接时,应以微体化石给出信息为主,同时参考蛇岩下部组分的同位素年代学数据。讨论了新疆东北部邻区和西部邻区蛇绿岩带的时代和性质,以及这些蛇绿岩带的对此