Preliminary Study on Paleoearthquake Chronology on the Northern Liulengshan Piedmont Fault in Yangyuan, Hebei Province, China

The northern Liulengshan piedmont fault is located along the southern margin of the Yangyuan basin and represents a dip-slip normal fault,generally NEE-trending and NNW-dipping.Landforms offset by the fault are fairly developed and well preserved in the Dushanpu area of Yangyuan County,Hebei Province.Two trenches were excavated in front of a scarp of the northern Liulengshan piedmont fault at Dushanpu and two paleoseismic events were revealed in the trenches,from which several samples were collected for dating.The samples were dated using the IRSL dating technique.The preliminary result shows the possible ages of the two paleoseismic events.     

AN EXPERIMENTAL STUDY OF INFILTRATION AND EROSION UNDER SLOPE GRADIENTS AND VEGETAL COVERS

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微波波段大气的衰减作用之实验研究

本文研究了微波波段(λ=5mm-3.2cm)大气的衰减作用。用微波辐射计,根据太阳射电法和大气辐射法进行大气微波吸收值的测量,同时用探空记录计算大气微波吸收值,两者进行比较和分析它们的相关。本文研究了大气微波吸收值与大气总水汽含量或地面气象要素(如温度、比湿)之间的关系,提供预告大气微波吸收值的可能性,云层对于大气吸收值的影响,文中也作了讨论。     

A STUDY ON ABSORPTION CHARACTERISTICS OF THE ATMOSPHERIC WINDOW IN MICROWAVE BAND

The absorption characteristics of the atmospheric window in the microwave band (λ=8.5 mm and 3.2 cm) are studied. The results measured in Beijing by using both solar radiation method and atmospheric radiation method arc compared with the values calculated from the radiosonde data so as to analyze their correlativity. The relationship between atmospheric window absorption and total column water vapour content is also discussed. The effects of clouds on the absorption are described.     

LAND USE AND LAND COVER CHANGE IN CHINA

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MULTI-OBJECTIVE PROGRAMMING MODEL OF TROPICAL CROPS IN HAINAN ISLAND

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Ophiolites from the Mianlue Suture in the Southern Qinling and Their Relationship with the Eastern Paleotethys Evolution

The Mianlue suture extends from Derni-Nanping-Pipasi-Kangxian to the Lueyang-Mianxian area, then traverses the Bashan arcuate structure eastward to the Huashan region, and finally to the Qingshuihe area of the southern Dabie Mountains. From east to west, with a length of over 1500 km, the ophiolitic melange associations are distributed discontinuously along the suture. The rock assemblages include ophiolite, island-arc and oceanic island rock series, indicating that there existed a suture zone and a vanished paleo-ocean basin. The Mianliie paleo-ocean basin experienced its main expansion and formation process during the Carboniferous-Permian and closed totally in the Triassic. It belongs to the northern branch of the eastern paleotethys, separated from the northern margin of the Yangtze block under the paleotethys mantle dynamic system.     

Extension of the Louzidian Metamorphic Core Complex and Development of Supradetachment Basins in Southern Chifeng, Inner Mongolia, China

The Louzidian metamorphic core complex (LMCC) in southern Chifeng is located on the northern margin of the North China craton. Structural analyses of the LMCC and its extensional detachment system indicate that the LMCC experienced two-stage extension. The ductile regime experienced top-to-northeast shearing extension and the brittle detachment fault underwent top-down-outwards slipping. Between these two stages, a semi-ductile regime recorded the transition from ductile to brittle. The hanging wall of the detachment fault is similar to those classic supradetachment basins in western North America. Analyses of provenance and paleocurrent directions in the basins show that there were two filling stages. In the early stage, materials came from the southwest margin of the basin and the hanging wall of the detachment system and were transported from southwest to northeast; while in the late stage, deposits were derived from the footwall of the detachment fault and transported outwards to the two sides of the     

BASIN-RANGE SYSTEM EVOLUTION OF QINLING-DABIE OROGENIC BELT AND ITS IMPACT ON REGIONAL ENVIRONMENT

As the structural body related to temporal-spatial evolution and tectonic dynamic system, the orogenic belt and basin are not only dependent on each other in space but also closely related with each other in terms of infrastructure, matter transference and dynamic mechanisms. By using apatite fission-track method, the authors firstly analyze the uplift and denudation ratios of the Qinling-Dabie orogenic belt, and by using tectonically detbrmed combination analysis and tectonic-thermal simulation the main geological occurrences are also illustrated. It is found that there must have had multi-phase differential uplift and denudation phenomena in the Qinling-Dabie orogenic belt during the Mesozoic-Cenozoic. Then, the regional evolution pattern of qualitative and quantitative denudation process is obtained during the post-orogenic period. On the basis of summarizing evolution process of the basin-range system in the Qinling-Dabie orogenic belt during the Mesozoic-Cenozoic and its effects on regional environ     

PETROGENETIC AND METALLOGENETIC AGES FOR THE PORPHYRY COPPER DEPOSITS IN THE GANGDISE METALLOGENIC BELT IN SOUTHERN TIBET

In the Gangdise area in the south of Qinghai-Tibet Plateau, a set of calc-alkalinevolcanics-granitic intrusives, which were resulted from subduction of neo-Tethys Ocean at YurlungZangbo oceanic plate beneath Lahsa block in Cretaceous-Palaeogene and subsequentarc-continental collision, were exposed, together with a set of shoshonitic volcanics and hypabyssalporphyries developed in the later stage (Bureau of Geology and Mineral Resources of TibetAutonomous Region, 1993; Li, 2002; Zhao et …