Gold-Platinoid Mineralization of Metasomatically Altered Ultramafites in Precambrian Protrusions of Mamynsky Geoblok

On the contiguous territories of Russia and Chi-na,along the left and right banks of the Amur Riv-er (Heilongjiang Province of China,and Amur Oblast' of Russia),among the Late Mesozoic ter-rigenous and volcano-plutonic formations,several Precambrian prot…     

Two Different Dust Storms in Northeast China:the Sources and Influences in East Asia

Dust storms in Northeast China become more se-rious in recent years due to the global warming and local land use and cover change (LUCC) around the sand lands in western and northwestern Jilin Province. Field investigations and urban testing re-vealed that the amount of dusts brought by dust storm reaches a higher level in the past two years. According to an experiment on the “mud-snow”in April, 2000 and an observation in March, 2002, the dusts coming from the western Jilin and fall…     

Analysis of runoff characteristics in midstream of Yinma River

To use the water resources reasonably in the midstream of Yinma River is of great significance to Changchun City which is short of water. With the runoff data of physical measuring, the paper analyses the characteristics surface rtmoff of the area, by means of the groundwater flow numerical simulation, and represents the characteristics of the groundwater runoff in the area. Based on combination analyses of the two runoffs, the authors point out the problem of the water resources use in this area and bring forward a resolution of conjunctive regulation and storage of the surface water and groundwater.     

Problems of ecological and technical safety by exploration and production of natural gas hydrates

Gas hydrates-the firm crystal connections formed water （water, ice, water vapor） and low-molecu- lar waterproof natural gases （mainly methane） whose crystal structure effectively compresses gas： each cubic meter of hydrate can yield over 160 m^3 of methane. In present time exploitation of the Messoyahsk （Russia） and Mallik （Canada） deposits of gas hydrates in is conducted actively. The further perfection of prospecting methods in the field of studying gas hydrates containing sediments in round extent depends on improvement of geophysical and well test research, among which native-state core drilling is one of the major. Sampling nativestate core from gas hydrates sediments keeping not only original composition, but structural-textural features of their construction. Despite of appeal of use gas hydrates as the perspective and ecologically pure fuel possessing huge resources, investigation and development of their deposits can lead to a number of the negative consequences connected with arising hazards for maintenance of their technical and ecological safety of carrying out. Scales of arising problems can change from local up to regional and even global.     

Characteristics of Quaternary deposits near Songjianghe Town on west slope of Changbai Mountain

1GeologicalsettingThe researched area is located at the east margin of Eurasia plate and is 50 km from Changbaishan Vol-cano to west. The average elevation of the studied area is about 1 200 m and rivers flow mainly from the east to the west. There are To…     

Types and formation mechanism of collapse in Tianchi region of Changbai Mountain

Collapse is a disaster in Changbai Mountain area.Based on the present stage of collapse,the anthors summarized three types of collapse and analyzed their formation mechanism.This research makes sense to further study.     

Stability analysis on Jinjia dam hydropower project in Chongqing City

The stability analysis is one of the chief problems at hydropower stations.The Jinjia Hydropower Station is a significant project in Southwest China.The paper adopts the rigidity limited equilibrium theory and evaluated stability of the slope body,which will provide the evidences for further detail design.     

Geochemical characteristics of Early Cretaceous source rocks in Boli Basin

The Early Cretaceous deposits are composed of important source rocks in Boli Basin. The types of the source rocks include black mudstones and coal （with carbonaceous mudstone）. By the organic geochemical analysis methods, the authors discussed the organic petrological characters, abundance of organic matter, degree of maturity and the type of source rocks. The main micro-component of black mudstone is exinite or vitrinite, and the content of vitrinite is high in coal. The weathering of the outcrop is very serious. The abundance of organic matter in source rock reaches the poor to better rank. The major kerogens in mudstone are type- Ⅲ, type- Ⅱ 2 and some type- Ⅱ 1 ; the organic type of coal is type-Ⅲ. The thermal evolution of the source rocks in every structural unit is very different, from low-maturity to over-maturity. The depositional environment is reductive, which is good for the preservation of organic matter. The organic matter in source rocks is mainly from aquatic organisms and terrigenous input.     

Stability analysis and treatment of No. 2 dump of Nanfen iron mine

On the basis of the study on the engineering geological characteristics of No. 2 dump of Nanfen iron mine and the analysis of the failure mode of dump landslide, the stability of the present dump, the stability of the dump 20 years later and the stability of double-bench dump are analyzed. Then, the debris flow risk is evaluated by fuzzy mathematics method. Finally, the comprehensive treatment for the dump is suggested. It is concluded that ① In rainy and snowmelt period, the stability would be decreasing sharply when ground water is not drained out in time; ② Double-bench dumping mode will improve stability of the dump little;③ Debris flow risk is middle danger. The interim debris flow with medium scale may occur. ④ Monitoring, draining and baffling work ought to be well done. ⑤In order to prevent the damage of landslide and debris flow, three measures are adopted, including setting rockfall net, setting the debris flow barrier and removing the residents.     

Sequence associations of sedimentary facies in continental basins and their applications to palaeogeographic mapping

According to the characteristics of sedimentary facies and their vertical associations, sequence association of sedimentary facies can be divided into 2 types and 28 subtypes. The first type (type A) is a sedimentary sequence without volcanic rocks, including 18 subtypes. The second type (type B) is a volcanogenic succession including 10 subtypes. Each subtype may reflect certain filling condition under certain sedimentary environment. Time and space distribution of different types of sequence associations can reflect tectonics that controlled the basin evolution, sedimentary environments and palaeogeography.