塔里木盆地瓦基里塔格辉长岩^40Ar—^39Ar年龄及其意义

瓦基里塔格位于新疆塔里木盆地塔中构造带 （即中央隆起） 的西部, 巴楚县城南东约４０ｋｍ 。这里发育一套轻微变质的碎屑岩哑地层, 其中有基性－超基性岩体侵入。对在此采集的２ 块辉长岩样品进行Ａｒ－Ａｒ定年, 获得的坪年龄分别为８２５．０±２．０Ｍａ 和８３７．３±２．０Ｍａ, 相应的等时年龄为８２１．４±８．０Ｍａ和８３３．３±１５．３Ｍａ。这是首次获得的塔里木盆地腹地较可靠的前寒武纪同位素年龄数据, 为塔里木盆地的构造类型、基底性质、组成和时代等地质问题的正确认识, 提供了一份重要的基础资料, 对于该地区的油气勘探部署也有十分重要的意义。     

水文工作回顾与展望

新中国成立５０年来,水文工作经历了迅速发展、曲折前进,改革开放三个发展阶段。新中国的水文工作在水文测验、水文情报预报,水文分析计算和水资源评价,水文科学研究,水文教育,水文国际合作与交流诸方面都取得了前所未有的巨大成就,为社会主义建设作出了巨大贡献。当前,中国水文工作面临着新的挑战和机遇,今后必须有新的发展,以满足新的迫切的社会需求。     

Geological Features of the Eastern Sector of the Bangong Co-Nujiang River Suture Zone: Tethyan Evolution

According to an analysis of the geological features in the eastern sector of the Bangong Co-Nujiang River suture zone, the Tethyan evolution can be divided into three stages. (1) The Embryo-Tethyan stage (Pz1): An immature volcanic arc developed in Taniantaweng (Tanen Taunggyi) Range, indicating the existence of an Embryo-Tethyan ocean. (2) The Palaeo-Tethyan stage (C-T2): During the Carboniferous the northern side of the Taniantaweng Range was the main domain of the Pa-laeo-Tethyan ocean, in which developed flysch sediments intercalated with bimodal volcanic rocks and oceanic tholeiite, and Pemian-Early Triassic arc granites were superimposed on the Taniantaweng magmatic arc; on the southern side the Dengqen-Nujiang zone started secondary extension during the Carboniferous, in which the Nujiang ophiolite developed, and the Palaeo-Tethyan ocean closed before the Middle Triassic. (3) The Neo-Tethyan stage (T3-E): During the Late Triassic the Dengqen zone developed into a relatively matural ocean basin, i     

A New Sauropod, Gongxianosaurus, from the Lower Jurassic of Sichuan, China

The paper describes an early and primitive sauropod dinosaur, Gongxianosaurus shibeiensis (gen. et sp. nov.), from the Dongyuemiao Member of the Lower Jurassic Ziliujing Formation in Shibei Township, Gongxian County, Sichuan Province, China, which is one of the 5 dinosaur fossils discovered in Gongxian in 1997. Except the skull which is incomplete, the fossils are well preserved. It has some features of both sauropods and prosauropods. It is an intermediate type in the evolution of dinosaurs from prosauropods to sauropods and provides materials for the study of the origin and evolution of the sauropod dinosaur fauna. The discovery of this new sauropod furnishes a way for the stratigraphic correlation between the Early Jurassic Ziliujing Formation in the Sichuan basin and the Lower Jurassic Lufeng Formation in the Central Yunnan basin.     

Hydrobios and Control of Eutrophication in Dongping Lake, Shandong Province

The Hydrobios in Dongping Lake, Shandong Province, mainly includes phytoplankton, zooplankton, benthic animals, fishes and hydrophytic vascular plants. Nitrogen and phosphorus are the restrictive factors for the growth and propagation of hydrophyta, therefore the key to the prevention and control of eutrophication in lakes lies in the control of the contents of the two elements in the water. Artificial fishing of algae can reduce the concentrations of trophic substances such as nitrogen and phosphorus in the water bodies, and biological measures may decrease the contents of these trophic substances in the bottom sediments and the water bodies, thereby playing an active role in modifying the eutrophication of the lake.     

松辽盆地三肇地区上生下储“注入式”成藏机制

三肇地区位于松辽盆地中部,是一个继承性深断陷－坳陷区。在上部坳陷中沉积了一套“上泥下砂”的地层。巨厚泥岩段底部的青山口组一段黑色泥岩是本区最主要的生油岩,在嫩江湖（Ｃａｍｐａｎｉａｎ）末期进入生油门限,明水期（Ｍａａｓｔｒｉｃｈｔｉａｎ）末期一早第三纪晚期（Ｃｈａｔｔｉａｎ）达到生烃、排烃高峰。在上覆大段泥岩封闭作用下,青一段地层形成超压,迫使油气向下排泄到下伏的扶扬油层储层。同时期,大量断开青一     

川西北马脑壳金矿床流体包裹体研究及对成矿条件的制约

川西北的马脑壳金矿床为一赋存于三叠系碎屑岩、碳酸盐岩系的大型微细浸梁型金矿床,通过详细野外地质调查和室内综合研究,可将矿床的热液成矿作用划分为四个阶段,应用均一法测得：Ｉ、ＩＩ、ＩＩＩ、ＩＶ阶段的成矿温度分别为１７５～２３０℃,１７９～２５５℃,１５７～２０７℃,１２０～２００℃,峰值分别为１９０～２１０℃,２００～２３０℃,１７０～１９０℃,１３０～１７０℃,盐度变化范围,Ｉ、ＩＩ、ＩＩＩ、ＩＶ     

Application of extension theory in risk zoning of debris flow in Beijing

The occurrence of debris flow is affected by many factors. Risk zoning of debris flow plays a vital role in the early-warning and prediction of abrupt geological hazards, and exploration of new method is needed in the early-warning and prediction of geological hazards. The extension theory is a new method to solve contradiction matters. Based on extension theory, AHP and GIS, the risk zoning model of debris flow was established in this paper. The result of this research provides a new way in the risk zoning, early-warning and prediction of debris flow     

“诱发前震”预测效能评价

“诱发前震”现象在区域地震活动中较普遍,据此提出A-F-B图象预报方法,以区域大震后短时间内发生的小震为预报因子,判断以后大震的位置并推测其震级与时间。为了检验该方法的实用性,统计了我国西南地区1970—1983年和华北地区1966—1984年的地震资料,对其预测效能做了统计评价。评分采用W值与R值。其中:W=1-(漏报率+虚报率);R=报对地震占有面积/应预报地震占有面积-预报区占有面积/研究区总面积。结果为W与R值都大于0.5,波动在0.5～0.8之间;并计算出各种不同预报参量的频数概率分布,给出了单次预报在取不同空间与时间范围的信度。