摘要:

AbstractFour detachment systems have been found in the Tarim Basin. They are made up of the Proterozoic, Palaeozoic, Mesozoic‐Eogene and Neogene‐Quaternary, respectively. The shallow‐level detachments are characterized by the occurrence of fold‐thrust belts in the Meso‐Cenozoic. The mid‐level detachments are marked by nappes, decollement folds and drag anticlines in the Palaeozoic. The deep‐level detachments are represented by ductile shear belts in the basement. Mid‐ and deep‐level detachments mainly occur in the Northern, Central and Southern Uplifts which are major hydrocarbon accumulation belts of large‐scale oil fields. Shallow‐level detachments mainly exist in the Kuqa, Southwestern and Southeastern Depressions, which are favourable belts for finding medium‐ and sma

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1992.mp5004001.x

出版商:Geological Publishing House    

年代:1992

数据来源: WILEY

摘要:

AbstractA number of Triassic (245–195 Ma) alkaline or subalkaline igneous complexes were discovered in the Yan‐liao area in the northern part of the North China platform. These complexes are all poor in SiO2; most of them are rich in Fe, Mg, K and P and such incompatible elements as Rb, Ba, U and Sr and REE; the initial87Sr/86Sr ratios range from 0.7055 to 0.7057. They might have originated in the altered upper mantle. On that basis coupled with the distribution of the Triassic System and the tectonic deformation, it is suggested that there should have existed a tectono‐magmatic belt in the area in Triassic time, which is an important manifestation of the Indosinian movement in the

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1992.mp5004002.x

出版商:Geological Publishing House    

年代:1992

数据来源: WILEY

摘要:

AbstractManganese nodules in areas CP and CC of the central Pacific are rich in REE. Comparatively speaking, the REE contents of nodules in area CP are hihger than those in area CC; and the REE contents of nodules from seamounts are higher than those of nodules from sea‐floor plains and hills. Within the nodules, the REE show a zonal distribution. The REE distribution patterns of the nodules are similar to those of the sediments and have a mirror image relationship with those of the sea water. Trivalent REE were not obviously differentiated when they entered into the nodules from the sea water.A major factor causing the difference of REE abundances between nodules and sediments is the redox conditions. The redox intensity of the ocean floor of the Pacific is controlled mainly by Antarctic Bottom Water (AABW). The iron‐bearing facies in the nodules is the main carrier of

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1992.mp5004004.x

出版商:Geological Publishing House    

年代:1992

数据来源: WILEY

摘要:

AbstractThe geochemical behaviors of hydrogen and oxygen isotopes in the hydrothermal system and their inherent relationship with the water / rock exchange are discussed in this paper. In addition to the temperature conditions, the effective W / R ratio is another factor controlling the changes in H and O isotope compositions of the altered rock and hydrothermal water. Besides, the application and geological significance of the water‐rock exchange theory are also discussed in the light of the H and O isotope compositions and their variation characteristics of the mineralizing hydrothermal water and altered rocks from several mineral deposits. Finally, a brief evolutional model of H and O istotope compositions of meteoric and magmatic hydrothermal waters in a hydrothermal system is give

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1992.mp5004006.x

出版商:Geological Publishing House    

年代:1992

数据来源: WILEY

摘要:

AbstractThe vegetation has been poisoned by gold in the western Guangdong‐Hainan region. The gold content of the leaves there is as high as 10‐1961 times the abundance, the chlorophyll content is 10%‐30% lower than that of the vegetation in metamorphic terrains and 10%‐20% higher than that in granite terrains, and the carotenoid content is 10%‐44% lower than the background value. The water content of leaves is 10% to 20% lower than the background value. The cells of leaves are deformed and broken. The leaf surface shows colour spots and becomes yellow or dark green. The spectral reflectance of the leaf surface is 5%‐30% higher than the background value; the spectral shape has shifted 5‐15 nm to the short wavelength. The gray scales of eanopy on images of Landsat TM and airborne imaging scanner (AIS) are 10%‐100% higher than the background values. On Landsat TM and AIS false colour images, plants poisoned by gold display a yellow color, which disinguishes them from background plants. According to the spectral and image features of gold biogeochemical effects, the author has constructed a gold information system and expert prediction system, and thus two gold target areas and two gold prospect areas have been identified rapidly, economically and accurately in the western Guangdong‐Hainan region which is extensively cove

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1992.mp5004007.x

出版商:Geological Publishing House    

年代:1992

数据来源: WILEY

摘要:

AbstractThe Ordovician Changtu Fauna is recently discovered in the Xia' ertai and Hulan Groups in northern Liaoning‐central Jilin. The fauna, containing 10 genera and 14 species (including 3 new genera, 9 new species and an unidentified species), is closely related in evolution with the Early Cambrian Qinghezhen Fauna. The discovery of this fauna is significant to the study on the age of the strata, Ordovician biostratigraphy and geological evolution of the tectonostratigraphical terrane on the northern margin of the Sino‐Korean pl

ISSN:1000-9515    

DOI:10.1111/j.1755-6724.1992.mp5004008.x

出版商:Geological Publishing House    

年代:1992

数据来源: WILEY