广东金史金多金属矿地质特征与成矿远景

金史地区位于灯塔盆地北西侧边缘,河源深大断裂下盘,石背岩体的外围。区内矿床具成矿时代新,矿化面积广,构造控矿作用明显等特征。成矿作用与盆地演化过程中构造活化、岩浆岩侵入关系密切,区内"三源"成矿条件充分,且共伴生矿发育,具有一定的成矿规模及远景。主要对该区成矿特征、矿床成因机理及成矿远景进行探讨。     

湖南津市黄牯山第四纪泥砾混杂堆积成因探讨

湖南省津市黄牯山发育一套泥砾混杂堆积,前人曾认为属冰川成因。近年笔者对该套堆积的沉积层序、结构组成、横向变化、砾石组构与表面特征等作了详细考察,发现堆积中下细上粗的层序特征,砾石扁平面的优选定向,沿层理经差异风化和磨蚀所形成的假"冰川擦痕",由壳状裂口经磨蚀、圆化所形成的凹面石,沉积体短距离内的相变,以及周边仅有低矮丘陵的地貌背景等,表明泥砾混杂堆积为泥石流产物,而不是冰川成因。     

Using Long-Period Body Wave to Inverse Moment Tensors of the M_S6.8 Jiashi,Xinjiang Earthquake in 2003 and the Moderate and Small Earthquakes before and after It

An Ms6.8 strong earthquake took place in Jiashi, Xinjiang on February 24 of 2003. The digital wave form data recorded in Kashi and Wushi stations are selected to inverse the moment tensor solutions for the strong earthquake and the moderate and small earthquakes before and after it （ 108 earthquakes in 2001 - 2004）. 67 focal mechanism solutions have been calculated, and the results agree with those from Harvard University and USGS. The analysis reveals that before the strong earthquake, the moderate and small earthquake distribution was dispersed, and after the event the distribution was mainly concentrated around the strong earthquake. Before the strong earthquake, the seismic faults of the mid and small events had the character of strike-slip and normal faulting, and after the event, they exhibit strike-slip and thrust faulting. The region is dominated by near-NS horizontal compression from the southern block after the strong earthquake.