苡茨河泥石流地质灾害及防治

据统计,1992~2013年苡茨河曾多次发生泥石流地质灾害,并造成村民生命财产巨大损失。2013年7月24日再次爆发泥石流,破坏农田71280m2(108亩)。因此在对苡茨河泥石流形成条件、活动特征分析基础上,分析其泥石流的形成机制及其造成巨大危害的原因,预测其发展趋势,在已有治理措施的基础上,提出两种防治对策进行对比,得出一个较为合理的防治方案。     

Geochemical and Sm–Nd isotope–geochemical patterns of metavolcanic rocks,diabase, and metagabbroids on the northeastern flank of the South Mongolian–Khingan orogenic belt

The first results of geochemical and Sm–Nd isotope–geochemical studies of metavolcanic rocks, metagabbroids, and diabase of the Nora-Sukhotino terrane, the least studied part of the South Mongolian–Khingan orogenic belt in the system of the Central Asian orogenic belt are reported. It is established that the basic rocks composing this terrane include varieties comparable with E-MORB, tholeiitic, and calc-alkaline basalt of island arc, calc-alkaline gabbro-diabase, and gabbroids of island arcs. Most likely, these formations should be correlated with metabasalt and associated Late Ordovician gabbro-amphibolite of the Sukdulkin “block” of the South Mongolian–Khingan orogenic belt, which are similar to tholeiite of intraplate island arcs by their geochemical characteristics.     

Granitoids of the Kongo Magmatic Zone of the Omolon Massif (Northeastern Russia): Rock Composition,Age, and Geodynamic Setting

Geotectonics - In our study we analyzed the composition of granitoid rocks within the Kongo magmatic zone of the Omolon median mass. The studied calc-alkaline granitoids cut through the Early...     

“十三五”期间中国探矿权及地质勘查投资时空演变

基于详细的统计数据,从时间、空间、结构等多个纬度,对中国探矿权及地质勘查投资情况进行了时间序列、因素相关性等对比分析和综合研究,为政府管理部门制定政策和规划提供参考依据。通过研究,揭示了影响探矿权及地质勘查投资的主要因素、底层逻辑和发展规律,并认为受国内外宏观经济增速放缓、地缘政治等因素影响,特别是国内相关产业政策、生态和环境保护压力,“十三五”期间中国探矿权数、地质勘查投入和新发现矿产地持续大幅度减少。“十三五”期间,新立探矿权同比减少52.1%,注销探矿权数是“十二五”期间的3.7倍多。油气矿产的探矿权登记面积和地质勘查投资分别占全国的96%和77.6%;非油气矿产探矿权数占全国的90%以上,有近60%的非油气探矿权在西部地区;非油气地质勘查投资中,水工环及科技等投资额占居半壁江山。预计中国在能源矿产、战略性矿产等勘查领域将增加勘查投入,地质勘查投资将于2024年后逐渐走出低谷。     

中国煤层气资源控制程度及可靠性分析

准确认识深部条件下气体和水分的赋存状态、相对含量及分布特征,对煤层气高效勘探开发具有重要指导意义。基于理论模型、分子模拟和气水演变分析,明确了煤层中气、水的赋存状态,揭示了气、水动态运聚界限和动态演化过程。考虑煤−水界面作用、水的可动性及赋存状态,煤中水可分为可动水(重力水和毛细水)、束缚水(吸附水、沸石水、结晶水和层间水)、结构水,其中毛细水、重力水和吸附水由孔隙主导,沸石水、结构水、结晶水和层间水由矿物主导。分子模拟结果显示,水分子在0.7 nm孔隙中可以饱和充填,吸附和解吸路径一致,在更大孔隙中出现弱吸附层和自由态。水分子吸附过程表现为单分子含氧基团吸附、单层强吸附、多层弱吸附、水团簇形成和充填孔隙等阶段。甲烷分子在1.5 nm孔隙可存在3层稳定充填吸附,在较大孔隙中(>1.5 nm)即以单层吸附和游离态共存,游离态在介孔及更大孔隙中普遍存在。结合上述吸附−游离气存在界限,改进了游离气和吸附气理论计算公式,为含气量计算提供新思路。深部热成因煤层气是煤大规模生排烃之后的残余气,在排烃过程中发生气驱水和水分蒸发扩散,残余水分为束缚水和结构水,后期无法改变。假定静水压力20 MPa,在0、5、10、15和20 MPa储层压力下,外来水分可入侵最大孔径为7、9、13、27 nm和不侵入。受差异保存条件控制,煤成气除了形成超压和欠压等差异含气系统外,还可能在煤系形成多类型含气模式。上述研究明确了煤层气、水微观赋存机制及形成演化模式,对深部煤层气富集特征及高效开发设计具有指导意义。

     

Validity of the Bouchet’s complementary relationship at 102 observatories across China

Bouchet in 1963 hypothesized that for large homogeneous land surface with minimum advection of heat and moisture, there exists a 1:1 complementary relationship of potential and actual evaporation coupled through land-atmosphere feedbacks. The complementary relationship has been widely used to estimate regional actual evaporation and explain the pan evaporation paradox. We examine the standardized potential evaporation (potential evaporation divided by wet environment evaporation) at 102 observatories at different elevations across China. Generally, the relationship is appropriate at the low elevations (<1000 m). With the increase of elevation, vapor transfer power becomes much less than radiation energy budget because of lower vapor pressure deficit and stronger global solar radiation. As a result, at the high elevations (over 1000 m), the excess energy resulted by limited moisture availability is not enough to be converted into drying power of the air. This result suggests that the complementary relationship is asymmetric at the high elevations. Supported by the Presidential Special Award Foundation, the Chinese Academy of Sciences (Grant No. O7R70020SD) and the National Key Technology R & D Program (Grant No. 2006BAC08B0408)     

The prospects for modernizing very broadband seismometers

This paper considers the possibilities for modernizing the KSESh broadband seismic station developed earlier at the IPE AS USSR. The goal of the modernization was to extend the frequency and dynamic ranges and to decrease nonlinear distortions. The ways and concrete methods for improving the mechanical construction and electronic components of the station are shown and the intermediate results are described. As preliminary estimates show, there is an opportunity to build devices with the velocimeter response up to 520–540 s periods on the basis of this pendulum.     

Possibilities of interpretation of the magnetotelluric data,obtained on a single profile over 3D resistivity structures

Magnetotelluric soundings are frequently carried out on a single profile or on profiles remote from each other. Interpretation of the obtained data is difficult in the presence of spatially heterogeneous geoelectric structures. We evaluate its capabilities on the basis of the synthetic data, that correspond to a geoelectric model, which consists of a three-layered section in the background and three rectangular prisms, differently arranged relative to the profile. Using the simple methods of analysis of magnetotelluric data, we succeeded in allocating all three heterogeneities over the area that surrounds the profile of observations. As a result of the fast smoothed-structure 1D and 2D inversion of different components of data, taking into account their specific features, the depths of the occurrence of anomalies and the order of the values of their electrical resistivity were evaluated, and the background section was also reconstructed. On this basis, and, also, with the use of a priori geological-geophysical information, the construction of a 3D model in a more or less broad band around the profile and its correction with the aid of 3D data inversion are possible.