摘要:

AbstractThis paper summarizes the Late Palaeozoic, Indosinian and Yanshanian palaeotectonic settings in the peri‐Pacific region of East Asia. On that basis, the Himalayan crustal movement in the region is divided into the early and late tectonic stages and two principal tectonic phases. From the ocean to the continent, 5 gigantic Himalayan formation‐ deformation belts are distinguished; they are the Northwest Pacific trench‐ island arc belt, the Northwest Pacific marginal sea basin belt, the East China Sea‐ northern South China Sea continental‐shelf down‐faulted belt, the East Asian epicontinental rift belt, and the East Asian intracontinental rift belt. The Early and Late Himalayan tectonic evolution is dealt with. Finally the state of the Himalayan regional stress field and its evoution in the region are discussed. It is considered that the mechanism of their formation is closely related to the continent‐ocean and surface‐deep ea

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1990.mp3003001.x

出版商:Geological Publishing House    

年代:1990

数据来源: WILEY

摘要:

AbstractInvestigations on stratigraphy, geomorphology and neotectonic movement in the Eastern Kunlun Mountains show that there existed a series of ancient lakes, including some saline lakes, in the studied region about 30,000 years ago. They were distributed south of the middle Kunlun fault, from the middle‐upper reaches of the present Narin Gol River in the west to the Alag Lake‐Tosou Lake in the east. Of these the ancient Narin Gol Lake and Kunlun Lake were mainly recharged by the hot water related to valcanos, so the B, Li and K contents are relatively high.The neotectonic movement that commenced at 30,000 a B.P. caused the river system in the Eastern Kunlun Mountains to invade southwards; as a result the ancient lake water was captured to recharge the Qarhan area. Therefore, the hot springs related to recent volcanism and faulting on the southern bank of the upper reaches of the Narin Gol River became an important source of saline materials for the Qarhan L

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1990.mp3003002.x

出版商:Geological Publishing House    

年代:1990

数据来源: WILEY

摘要:

AbstractThe ore‐controlling mechanism of the bedding fault system in the massive sulfide deposits of the Wushan copper orefield may be generalized as the control of ore deposition by optimum surface in an ore‐ forming structural trap. The mechanism has three major features: (1) timing of mineralization; (2) positioning of host formation; and (3) dependence of ore‐controlling structure on properties of rocks. The “optimum surface” is a divisional structural plane which marks obvious difference in physical, chemical and mechanical properties and is favorable for mineralization. It is also a unity of structures, lithofacies and orebodies.The structural and geochemical characteristics of the ore deposits indicate the migration trend of the major characteristic elements in the ore‐ controlling fault belt: elements with a small radius (Si, Fe, Mg and Al) moved towards and concentrated at the center of the belt while large‐radius ones (Ca, K and Na) were remote fr

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1990.mp3003003.x

出版商:Geological Publishing House    

年代:1990

数据来源: WILEY

摘要:

AbstractProterozoic rocks in the northeastern Jiangxi‐southern Anhui may fall into three rock associations which belong to different but interrelated tectono‐palaeogeographic units. The field geological and petrochemical characteristics of the northeastern Jiangxi‐western Zhejiang volcanic zone indicate that it was once an island arc zone. An analysis of the sedimentary characteristics of Proterozoic turbidites lying north of the zone has revealed the history of development of a back‐arc basin. According to the type of the Proterozoic rock formation south of the zone, it may be deduced that the formation might represent the fore‐ arc and French areas. By means of various tectono‐palaeogeographic analyses, the relation between the island arc zone and the back‐arc basin is inferred and the Late Proterozoic tectono‐ palaeogeographic development is discussed by using the model of the trench

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1990.mp3003004.x

出版商:Geological Publishing House    

年代:1990

数据来源: WILEY

摘要:

AbstractThe granitoids of the continental crust transformation series in South China may be divided into three types: (1) synorogenic migmatic and magmatic type, (2) anorogenic continental crust anatexis type, and (3) syncollision type. Based on the results of Sr and Nd isotopic determinations, the source material composition of the three types of granitoids is calculated with crust‐mantle binary mixing simulation. The calculations indicate that the granitoids of the first type consist of 78.6‐89.7% upper crust endmember materials and 15.0‐10.3% depleted mantle endmember materials, the granitoids of the second type are composed of 63.7% upper crust endmember materials and 36.3% depleted mantle endmember materials, and those of the third type 100% upper crust endmember materials. Hence, the source material composition of the granitoids of all the three types is dominated by upper crust endme

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1990.mp3003005.x

出版商:Geological Publishing House    

年代:1990

数据来源: WILEY

摘要:

AbstractOn the basis of geological studies of skarn deposits in China and by using thermodynamic models of the solid solution, the coexisting clinopyroxene‐ garnet pair in skarn deposits has been analysed and a coexisting clinopyroxene‐garnet acidometer developed. They can be used to estimate the medium condition under which the skarn was formed. The research on the acidity for the formation of various metallic skarn deposits in China suggests that skarns endowed with dissimilar types of mineralization and occurring in diverse environments differ in the acidity conditions for their formation and in the trend of acidity variation of ore‐bearing fluid. This, coupled with the study of oxygen fugacity of coexisting minerals, makes it possible to establish the oxygen fugacity‐ acidity facies of skarn deposits, which reflect the close genetic relationship between the metallization and the formation o

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1990.mp3003006.x

出版商:Geological Publishing House    

年代:1990

数据来源: WILEY

摘要:

AbstractThe Middle‐Upper Cambrian boundary is one of the current stratigraphical problems which remain open in the geological world, since there have been no universally acknowledged delimiting standard and stratotype. Acting on the instruction of Profs. Lu Yanhao and An Taixiang the author studied in details the Paibi Section, which is well exposed as a continuous sequence at an easily accessible locality. The Middle‐Upper Cambrian boundary strata are composed of biocalcimicrosparite, indicating the sedimentary environment of an underwater upheaval on the gentle slope along the frontal margin of the Yangtze carbonate platform.For the upper Middle and lower Upper Cambrian agnostid trilobite zones and conodont zones are erected, and a more accurate correlation between the trilobite and conodont sequences is established. Based on these, the Middle‐Upper Cambrian boundary is drawn more reasonably and precisely than what was done before. In short, the section studied is superior to other known sections of Middle‐Upper Cambrian, and it will probably be an ideal candidate for the Middle‐Upper Cambrian boundary s

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1990.mp3003007.x

出版商:Geological Publishing House    

年代:1990

数据来源: WILEY

摘要:

AbstractThe geothermal field is mainly controlled by the regional tectonic framework characterized by alternations of uplifted and depressed basement, and exhibits a similar zoned distribution of temperatures. In the uplifted area the geothermal gradient (G) and terrestrial heat flow value(q) of the Cenozoic sedimentary cover are relatively high, with G = 3.5 − 5.0°C / 100 m and q = 63‐84 mW / m2; whereas in the depressions they are relatively low, with G = 2.7−3.5°C / 100 m and q = 46‐59 mW / m2. In the whole region, Ḡ = 3.581°C / 100 m and q = 61.5± 13.4 nW/ m2, indicating a comparatively high geothermal background and the presence of local geothermal anomalies. A comparison of the results of mathematical simulation of the geothermal field with the measured values shows a good agreement between them. The geothermal difference between various tectonic units is caused chiefly by the lateral and vertical variation of thermal properties of shallow crustal rocks. This phenomenon can be regarded as the result of redistribution of relatively uniform heat flows from the deep crust in the surficial part of the crust in the process of their upwa

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1990.mp3003008.x

出版商:Geological Publishing House    

年代:1990

数据来源: WILEY