Mantle processes during ocean formation：Petrologic records in peridotites from the Alpine－Apennine ophiolites

Mantle peridotites were early exposed at the sea-floor of the Jurassic Tethys derived from the subcontinental mantle of the Europe-Adria system. During continental rifting and oceanic spreading, these lithospheric peri-dotites were percolated via diffuse reactive porous flowby melt fractions produced by near-fractional melting of the upwelling asthenosphere. Ascending melts inter-acted with the lower lithosphere, dissolving pyroxenes and precipitating olivine, and crystallized at shallower levels in the mantle column causing melt impregnation.Subsequent focused porous flow formed replacive dunitechannels, cutting the impregnated oeridotites, which were conduits for upward migration of MORB-type liq-uids. Melt migration produced depletionlrefertilization and significant heating of the percolatedlimpregnated mantle, i.e the thermochemical erosion of the litho-sphere. Impregnated and thermally modified lithos-pheric mantle was cooled by conductive heat loss dur-ing progressive lithosphere thinning and was intrudeaby MORB magmas, which formed Mg-rich and Fe-richgabbroic dykes and bodies. Alpine-Apennine ophiolitic peridotites record the deep-seated migration of melts which changed their compositions and dynamics during the rift evolution. The thermochemical erosion of the lithospheric mantle by the ascending asthenospheric melts, which induces significant compositional and rhe-ological changes in the lower lithosphere, is a major process in the evolution of the continent-ocean transi-tion towards a slow spreading oceanic system.     

华南首次发现断层眉脊带

笔者在湘西北地区进行地震地质考察时,于澧县南约20km的观音庵东侧尺马山一带发现了北东走向的断裂眉脊带,这是首次在华南地区发现断层眉脊带,这将有助于对华南地区活断层与地震断裂的研究。 尺马山(海拔高度132m,下同)与其东北的担良山(151m)及其西南的银珠山(241.6m)构成走向N30～     

湘中锰矿控岩控矿构造遥感地质分析

应用遥感信息结合其他地学资料综合分析湘中锰矿构造型式及控岩控矿地质特征，提出东西向和北东向同期构造与台地边缘相带共同控制锰矿的新认识。     

遥感技术在构造地质研究及成矿预测中的应用

遥感技术在构造地质研究及成矿预测中的应用杨武年，朱章森（成都理工学院）本文应用现代化遥感技术，根据遥感多波段图像信息量大、对地质构造形迹显示的宏观性、信息连续性以及对隐伏构造具“透视”作用的特点，并据遥感横张大节理和剪切节理与宏观褶皱及断裂具有成因联...     

地层倾角测井矢量图模式识别与构造解释系统

本文介绍了地层倾角测井矢量图模式识别与地质构造解释系统的设计原理和基本方法。文中利用Ｆｉｓｈｅｒ方法划分构造段，利用极差分层和归并，通过模糊数学的方法进行模式识别，通过井钻的模式识别结果给出井位所在地的地质构造解释。本系统已在ＩＢＭＰＣ／ＸＴ及其兼容机上实现，对胜利油田和中原油田的２３个实际测井数据进行了实验，判别和解释正确率达到９０％。     

1987年南半球夏季南设得兰群岛邻近海域CWB的特征及其成因

本文利用1987年1-2月中国第三次南极考察期间在南设得兰群岛邻近海域获得的STD资料,详细阐述了群岛以北海域中的一条海洋峰——大陆水边界(CWB)在表层、次表层和深层的表观特征,并给出了测区表面的地转流分布,计算了斜压变形半径R_bc.作者认为这里沿锋向海流处于地转平衡状态,且锋主要由边界流的作用所致.CWB的沿锋尺度约360km,平均宽度约30km.