摘要:

AbstractThe tectonic nature of southern China has changed again and again in the Phanerozoic. In the Caledonian cycle, there existed three tectonic units‐the Yangtze paraplatform, Indosinian‐South China Sea paraplatforrn and Caledonian South China fold belt, of which the last unit is not a collisional orogenic belt but a scissor‐shaped aulacogen‐ type geosyncline opening towards Yunnan and Vietnam. In the Indosinian cycle, South China belonged to the Tethyan tectonic domain, and no abyssal oceanic basin existed there. Since the Late Triassic, especially in the Yanshanian orogenic stage, it became a component part of the peri‐Pacific continental‐margin activation belt of eastern Asia. No Alpine‐type orogenic belt occurs in the interior of the continent of s

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1991.mp4002001.x

出版商:Geological Publishing House    

年代:1991

数据来源: WILEY

摘要:

AbstractThe Kunyang Aulacogen is a continental rift which initiated at the beginning of the Middle Proterozoic. It was generated on the rigid continental crust represented by the crystalline Kangding Complex, and is bounded by two N‐S‐trending deep faults?Anninghe‐Luzhijiang Fault and Xiaojiang Fault. Its early stage of rupture was characterized by alkaline mafic igneous activities in the Dahongshan Group and Hekou Group. During the later tensile‐ depression stage the aulacogen evolved into a graben where sedimentation of the Kunyang Group took place. The sedimentary sequence comprises terrestrial red beds, algal dolomite, marine black shale and carbonate rocks which are quite typical of rift sedimentary association, and contains stratabound copper deposits of the well‐known Dongc

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1991.mp4002002.x

出版商:Geological Publishing House    

年代:1991

数据来源: WILEY

摘要:

AbstractVesignieite, Cu3Ba(VO4)2(OH)2, crystallizes in space groupC2/mwitha° = 1.0270(2),b° =0.5911(1),c° = 0.7711(2)nm and β =116.42(3)°. The intensity data were collected with the RIGAKU RASA‐IIS single‐crystal four‐circle diffractometer. The structure was determined by Patterson and Fourier methods and refined by the least‐square technique to a final R index of 0.051 for 614 independent diffraction points with |F|>3σ|F|.The crystal structure analysis shows that vesignieite has a layer structure parallel to (001).The powder diffraction lines w

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1991.mp4002003.x

出版商:Geological Publishing House    

年代:1991

数据来源: WILEY

摘要:

AbstractThree melting events of the eartr's crust occurred during the period of 220‐120 Ma in the Shandong Peninsula. Three subcycles of granitoid magma including six rock series were generated in the faulted granitoid magma belt. The parent magma of several rock series formed earliest originated from the lower crust of granulite facies; following the increase of geothermal temperature the source magma would migrate into the middle crust of amphibolite facies! In the diapiric granitoid magma belt, the granitoid magma was formed first in granitic layer of the upper crust, and then in the middle crust. In each subcycle the generation of magma started with the generation of more mafic one and finished with low eutectic one; they were formed in the form of layered melting in a particular position of the crus

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1991.mp4002004.x

出版商:Geological Publishing House    

年代:1991

数据来源: WILEY

摘要:

AbstractControlled by E‐W‐trending faults, a Proterozoic (1.4‐1.8 Ga old) rapakivi granite suite was intruded in Beijing and the area to its east (within Hebei Province), forming three parallel belts of igneous rocks. The isotopic, trace element and rare earth element geochemical data of a bimodal rock association made up of anorthosite, gabbro and alkali basalt and olivine‐bearing quartz‐syenite, rapakivi granite and trachyte as well as potassic A‐type granites and anorogenic granites— all suggest that there exists an incipient rift in the study area. Fractional crystallization of a mixed magma formed by the magma derived from the upper mantle and the magma derived by small degrees of fusion of the lower crust produced anorthosite cumulates. The water‐deficient granitic magma was differentiated into a subalkaline series. When the fractional crystallization was incomplete, rhythmic erupt

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1991.mp4002005.x

出版商:Geological Publishing House    

年代:1991

数据来源: WILEY

摘要:

AbstractThrough the study of the oxidized zone of the Debao skarn‐type Cu‐Sn deposit in Guangxi, the authors have found 14 arsenate minerais, most of which are for the first time reported in China. They are mainly Cu arsenate minerais with subordinate Cu‐Pb arsenate minerais and minor Fe‐Pb‐Ba varieties.Based on their paragenesis these minerais may be divided into the following series: (1) the clinoclasite‐olivenite‐cornwallite‐cornubite‐debaoite‐copper silicarsenate association, (2) the scorodite‐carminite‐beudan‐tite‐bayldonite‐ duftite association, and (3) the scorodite‐Ba‐bearing pharmacosiderite‐ dussertite association.Arsenate minerais are formed generally in the oxidized zone of the sulfide‐type deposits which lie in the warm, humid and rainy torrid‐subtropical zone with pH = 6‐8 and contain large am

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1991.mp4002006.x

出版商:Geological Publishing House    

年代:1991

数据来源: WILEY

摘要:

AbstractCenozoic basalt in eastern China contains abundant ultramafic xenoliths which are specimens of pyrolites released during basaltic magma eruption. A total of 405 P‐T data of pyroxene in the ultramafic rocks have been collected, which present a more precise pyroxene geotherm. The average geothermal gradient in the upper mantle represented by the pyroxene geotherm is about 3.3°C / km, which is much less than that derived from the conductive thermal model (≡ 14°C / km), implying the great significance of convective heat transfer. The calculation shows that the contributions of convective and conductive heat transfers are 79% and 21%, respectively. The perturbation in the thermal structure of the upper mantle is an important manifestation of the tectonothermal event of Cenozoic continental rifting and intense basaltic volcanism in eastern China. Based on the pyroxene geotherm and its comparison with the current geothermal field derived from the measurements of the surface heat flows, it is suggested that the Moho may be a secondary thermal boundary. The current geothermal field and the thermal structure of the lithosphere in eastern China may mainly reflect the result of the tectonothermal disturbance in the Neogene‐Quaternary, in other words, the lithosphere has just begun

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1991.mp4002007.x

出版商:Geological Publishing House    

年代:1991

数据来源: WILEY

摘要:

AbstractThis paper deals with the geographic distribution and geological setting of the Jehol (northeast Hebei‐southwest Liaoning‐southeast Inner Mongolia) fauna, and discusses the origination and the evolution of its major biological groups. It is demonstrated that the Yan‐Liao (northern Hebei‐western Liaoning) area is the provenance for the fauna. Why the fauna originated and developed in the area was intimately related to such factors as the palaeoclimate, palaeogeography, crustal movement, volcanism and frequent reversals of magnetic polarity at that time, in addition to the internal factors of the organisms the

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1991.mp4002008.x

出版商:Geological Publishing House    

年代:1991

数据来源: WILEY