Seismotectonic environment of occurring the February 3, 1996 Lijiang M=7.0 earthquake, Yunnan Province

Introduction The surface rupture and aftershocks of the February 3, 1996 Lijiang earthquake are basically distributed along the N-S-trending Lijiang-Daju fault, which is boundary fault between Lijiang Quaternary, fault controlled basin and Yulong-Haba range (ZHANG, et al, 1997). Corresponding to the surface geological features, the focal rupture of the Lijiang earthquake also shows large component of dip-slip. It is of great difference from that of other earthquakes in west Yunnan, in w…     

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.     

Magmatic effects of the lunar late heavy bombardment

Large volumes of mare basalts are present on the surface of the moon, located preferentially in large impact basins. Mechanisms relating impact basins and mare basalt eruptions have previously been suggested: lunar impacts removed low-density material that may have inhibited eruption, and created cracks for fluid flow [Icarus 139 (1999) 246], and lunar basins have long been described as catchments for magma (e.g., [Rev. Geophys. Space Phys. 18 (1980) 107] and references therein). We present a new model for melt creation under near side lunar basins that is triggered by the impacts themselves. Magma can be produced in two stages. First, crater excavation depressurizes underlying material such that it may melt in-situ. Second, the cratered lithosphere rises isostatically, warping isotherms at the lithosphere-asthenosphere boundary which may initiate convection, in which adiabatic melting can occur. The first stage produces by far the largest volume of melt, but convective melting can continue for up to 350 Ma. We propose that giant impacts account for a large portion of the volume and longevity of mare basalt volcanism, as well as for several compositional groups, including high alumina, high titanium, KREEP-rich, and picritic magmas.     

Geochemistry of the subduction-related magmatic rocks in the Dahong Mountains, northern Hubei Province——Constraint on the existence and subduction of the eastern Mianle oceanic basin

Being a composite collisional orogen between North China and South China blocks, the Qinling orogenic belt is the key to understand the composite combination, prolonged evolutionary history and their continental dynamics. The main suture between north and south Qinling, called Shangdan suture zone (SDSZ), had been studied in detail for about twenty years. Recently, another suture zone, called Mianl黣 suture zone (MLSZ), has been identified in the Qinling Mountains. It is characterized b…     

Development characteristics of interlayer oxidation zone type of sandstone uranium deposits in the southwestern Turfan-Hami basin

The known uranium ore and anomaly occur-rences are distributed mainly in the southwestern part of the Turfan-Hami basin. The focus of current explo-ration is placed on the leachable interlayered oxidation zone type of sandstone uranium deposits. Uranium deposits in the sedimentary basin can be classified into three types in accordance with their host rock types, i.e. the sandstone-type uranium deposits, the coal rock-type uranium deposits and the mud-stone-type uranium deposits. The sandstone…     

2003年淮河流域大水期间体积降水量的研究

针对 2 0 0 3年梅雨期淮河流域大水提出了体积降水量的概念及其计算方法 ,在计算出淮河流域和其各子流域逐日和总体积降水量的基础上 ,将体积降水量与水文站的水位和流量进行了对比分析。结果表明 :水位对累计体积降水量有较好的即时响应 ,流量对体积降水量有较好的延迟响应。另外 ,讨论了流域体积降水量的预报问题 ,用国内外数值天气预报产品和中央气象台指导预报产品 ,进行了流域体积降水量预报试验 ,并对预报结果进行了检验分析。结果表明 :在目前天气预报水平条件下 ,利用数值天气预报和中央气象台业务预报产品制作体积降水量是可行的 ,能够延长洪水预报的预见期 ;而且 ,数值天气预报产品在预报体积降水量方面有明显的优势 ,因此可以直接利用数值天气预报产品进行体积降水量的客观预报 ,为防汛工作提供重要的依据。     

柴达木盆地近40a气候变化及其对农业影响的研究

利用柴达木盆地6个代表站逐日平均气温、逐月降水资料以及逐日最低气温资料。对盆地40a来的气候变化特征进行分析。同时分析了气候变化对农业生产的影响。为充分利用变化了的农业气候资源。减少不利因素带来的影响提出了对策和建议。     

含煤盆地煤储层后期改造形式及对煤层气选区影响--以华北克拉通选区为例

阐述了改造型含煤盆地煤储层被改造的两种形式；煤体结构的改造及构造煤的形成原因；后生充填物对煤层孔隙的改造及形成原因。提出了以构造煤发育程度作为改造型含煤盆地改造强度的一个指标。概述了华北克拉通盆地由中生代剪压应力转化为新生代剪张应力和拉张应力，而在盆地内形成以挤压构造为主到伸展构造为主的演化历程，及不同构造类型的区域分布，指出这种演化极易形成构造煤和后生充填物。提出将华北克拉通含煤盆地分为3种改造类型及其分布区域，分析了各自区域的煤储层物性及对煤层气开发选区的影响。提出应重视鄂尔多斯盆地侏罗纪煤层的煤层气．研究与开发．     

豫西济源谭庄组河流沉积中的Stipsellus遗迹组构

豫西济源盆地上三叠统谭庄组下段为曲流河沉积。本文通过描述和分析谭庄组河流沉积特征，划分了4种不同河流沉积组合类型，识别出Stipsellus遗迹组构，并发现该遗迹组构常与曲流河沉积物伴生，可作为此类沉积的典型生物遗迹标志。其中，Stipsellus sp．A代表发育在河漫滩较浅水体下或潮湿的软底细粒沉积物中的一种遗迹组构类型；Stipsellus sp．B则代表发育在曲流砂坝上部的男一种遗迹组构类型。     

山西大同-阳高地震活动背景

通过对大同盆地历史地震活动及大同盆地历史地震活动与华北地震区、山西地震带强震活动的关系的研究，得出山西大同-阳高1989年6．1级地震活动是这一地区历史地震的延续，是华北北部中强地震活动的重要组成部分，具有广义前震的重要意义，其后对应发生的河北张北6．2级地震。标志着华北地震区的地震活动期已进入尾声。