摘要:

AbstractThe Middle Proterozoic Chartai Group separated by two unconformities consists of three depositional sequences: the Shujigou Formation‐Zenglongchang Formation (DS I ), the Agulugou Formation (DS II ), and the Liuhongwan Formation (DSIU). The carbonate platform and back‐platform basin are the basic environment model of the Chartai Group. The syndepositional faults on the oceanward side of the carbonate platform and large‐ scale slumping in the soft sediments are important marks of facies tracts. The newly established Zenglongchan uplifting, an epeirogenetic uplifting, plays an important role in the formation of the palaeogeographic framework of the Chartai Group. The stratigraphic correlation between the Chartai Group and the Bayan Obo Group is made for the first time by using sequence stratigraphic principie and model established by P.R. Vail. The Chartai Group, which was deposited on the northern passive continental margin of the North China platfom, represents the platform

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1991.mp4003001.x

出版商:Geological Publishing House    

年代:1991

数据来源: WILEY

摘要:

AbstractIn the Qinling orogenic belt, oceanic crust originated in the Early Palaeozoic, while the product of continental collision appeared as late as after the Triassic. The Late Palaeozoic records there are of major impor‐tance for understanding the tectonic regime at that time. The Carboniferous and even Permian sequences and the distribution of sedimentary facies in northern Huaiyang indicate that the rocks were formed in a large basin opening towards the south. Regional stratigraphic correlation shows that the interior of the Qinling orogenic belt was a sea trough lying between the Yangtze and North China plates in the middle part of the Late Palaeozoic. With subsequent northward migration of the South China Sea, the two seas were connected with each other. Both the mélanges and the Dabie block in the eastern sector of the Qinling belt were formed in the Mesozoi

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1991.mp4003002.x

出版商:Geological Publishing House    

年代:1991

数据来源: WILEY

摘要:

AbstractIn this paper such minerais as apatite, zircon and biotite from granites were determined and analyzed by secondary ion mass spectrometry (SIMS) for their isotopic ages, REE composition, trace elements and volatile components with an attempt to shed light on the origin and formation environments of the Jinningian granites in the Yunnan sector of the Kangdian (Xikang‐ Yunnan) earth's axis. The results show that the apatites, zircons and biotites of different geneses possess different fingerprint characteristics. Some correlations have been found between trace elements and volatile components contained in the minerais from grantie

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1991.mp4003003.x

出版商:Geological Publishing House    

年代:1991

数据来源: WILEY

摘要:

AbstractPhlogopite‐ and diopside‐ bearing dunite occurs as rounded inclusions in hornblende‐ diorite. The petrofabrics, mineral composition and abundances of the trace elements in the dunite indicate that the inclusions were derived from the upper mantle and are the residues of high‐ degree partial melting of mantle peirdotite. The study of trace elements in the inclusions and their host rocks shows that the magma was originated from the mantle which was enriched in incompatible elements by mantle metasomatism prior to the partial

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1991.mp4003004.x

出版商:Geological Publishing House    

年代:1991

数据来源: WILEY

摘要:

AbstractThrough studies on the element geochemistry, alteration of country rocks, ore‐forming fluids and isotope geochemistry of the Amo tin deposit in the metamorphic rocks of the Upper Proterozoic Ximeng Group, the authors consider that the concentration of the B‐F‐Li‐Rb‐Cs‐Sn association is related to acidic magmatism in the study area. The Fe‐ Mg‐ Li tourmaline in the ore is the replaced product of the country rocks by hypothermal fluid. The δ18O values of mineral separates are +2.01− +13.16%o and their δ34S values, +2.6−+7.2%o. The ore‐ forming materiais were derived from hydrothermal fluid of granitic magma. For the mineralization, the temperature is 450 ° ‐350°C, the pressure, 450‐1000 × 105Pa, and the age, Himalayan (21.5 Ma). According to the geochemical characteristics, a minerogenic model is established: the deposit is a hypothermal cassiterite‐quartz vein type tin deposit controlled

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1991.mp4003005.x

出版商:Geological Publishing House    

年代:1991

数据来源: WILEY

摘要:

AbstractKaolin deposits of weathering‐residual type make up a large proportion in different types of kaolin deposits and are widely used in ceramics, electron ceramics, rubber and paper industries. This paper discusses sys‐tematically this type of kaolin deposit with respect to their features of occurrence, mineralogical and chemical composition and transformation of minerais during supergene processes, thus providing some basic data for the rational exploitation and utilization of the kaolin resour

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1991.mp4003006.x

出版商:Geological Publishing House    

年代:1991

数据来源: WILEY

摘要:

AbstractThe Rehai geothermal field in Tengchong County, Yunnan Province is a significant high‐ temperature hydrothermal convective system. The geothermal reservoir is composed of granite. Various geothermometers are used to evaluate the reservoir temperature. The most likely temperature of the reservoir as represented by TNa‐K‐Cais about 230 °C. The chemical and isotopic compositions of fluids before boiling within the reservoir are estimated. The mixing and dilution of cold and warm waters are discussed. The Rehai geothermal field is a high‐ temperature (hot) water system with the subsurface boiling zone close to the surface. The reservoir pressure at different depths is calculated. And finally the water‐rock equilibration i

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1991.mp4003007.x

出版商:Geological Publishing House    

年代:1991

数据来源: WILEY

摘要:

AbstractThe marine Tertiary sequence in the north part of the South China Sea may be divided into 18 Late Oligocene to Pliocene calcareous nannofossil zones and one unnamed Eocene assemblage based on an analysis of calcareous nannofossils from 40 offshore boreholes. The unnamed Eocene assemblage has been found only on the northeast margin of the Zhujiangkou basin. The 18 cakareous nannofossil zones of the Late Oligocene to Pliocene were deposited in succession, but their development degrees are different. Among the 18 calcareous nannofossil zones, those corresponding to Martini's (1971) NN4‐NN5 zones, NN11 zone and NN13‐NN15 zones are well developed, relatively persistent laterally and also widely distributed. They are the important markers for the stratigraphical subdivision and correlation of the Upper Tertiary between the various basins in the north part of the South China Sea. Based on the calcareous nannofossils and the sedimentsry features coup‐led with the foraminifer zonation in certain basins, the present paper discusses the sedimentary characteristics of the marine Tertiary and as well as the distribution and development of the sedimentary hiatus in the region. The calcareous nannofossil markers for the Upper / Lower Tertiary and the Quaternary / Tertiary boundaries, and the characteristics and geological significance of the reworked calcareous nannofossils are also discussed in the

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1991.mp4003008.x

出版商:Geological Publishing House    

年代:1991

数据来源: WILEY