| 从古地理发展探讨中国东部白垩纪一早第三纪盆地找钾前景 |
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| 引用本文：.1988.The prospect of potash search in the cretaceous-paleogene basins of eastern china as viewed from paleogeographical evolution[J].Mineral Deposits,7(3):79~88 |
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| 中文摘要:白垩纪一早第三纪期间，中国东部发育了一系列大小不等的沉积盆地，在干旱气候下，其中堆积了丰富的盐类物质。本文从宏观的角度，也就是从古构造的发展、古地理的演变以及气候带的推移等等方面来认识盐类沉积时空分布的规律性。在空间上，中国东部燕山至南岭之间的地区可划分为六个不同的盆地区和隆起区，在时间上有四个不同的成盐期。在此基础上来分析对钾盐沉积有利及不利的条件，进而探讨本区自垩纪一早第三纪盆地的找钾前景及方向。 |
| 中文关键词:古地理 构造发展 沉积盆地 找钾前景 中国东部 |
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| The prospect of potash search in the cretaceous-paleogene basins of eastern china as viewed from paleogeographical evolution |
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| Abstract:On the basis of the paleogeographic development and evolution, the prospect in search for Cretaceous-Paleogene potash-deposits in the region between the Yinshan-Yanshan Mountains and the Nanling Mountains of eastern China is discussed in this paper. An analysis of the paleotectonic and paleogeographic development that this region has some favorable conditions for potash prospecting. 1．In Cretaceous and Paleogene, there were a lot of sedimentary some of which had subsided deeply, forming uncompensational basins. During the evolution of the basins, lots of small basins might be confluent at times to give birth to some vast basins.In the late Cretaceous, the size of the basins reached the maximum, thus providing a vast basin for salt-deposition. From the paleogeographic and sedimentation characteristics, this region can be divided into some diffferent basin areas and uplift areas: 1)North China basin area;2)Sangdong-Jiaugsu uplift area; 3)Nan(yang)-Xiang(yang)basin area; 4)Jianghan-Dongting basin area; 5)Jiangsu-Anhui basin area; and 6)Fujian-Zhejiang-Jiangxi uplift area. In tile upilft areas, there existed only a few small faulted basins, but in the basin areas, there occurred some large basins, thus more favorable for the salt-deposition. 2．Sinze the Late Mesozoic, this region has been controlled by the arid climate zone, showing the tendency of continuous northward movement of the arid climate zone and the progressive intensification of the aridity. As a result, the gypsum and salt deposits are wide!y distributed. There were four main sale-deposition periods in Cretaceous-paleogene: 1)early Late Cretaceous(K12); 2)Paleocene-early Eocene(E1-E12); 3)late Eocene(E23); 4)early Oligocene(E12). Different periods had different salt-deposition ranges and sizes, and among them the third period seemed to be the optimum period in that the distribution of salt-deposits was most extensive and there were sonic manifestations of potash salt; it was therefore the most favorable period for salt-deposition. 3．There were various kinds of salt material supplies. Besides the terrigenous supplies, the transgression during the Cretaceous-Paleogene was one of the most important means of material supply for salt-deposition in the basins. In addition，the supply from the depth of the crust ought not to be ignored either. 4．Tile periodicity of tectonic movement was another important factor. When the tectonism was intense, the geomorphology became contractive, forruing solne closed basins; when the tectonic activities became comparatively weak, the brine was likely to concentrate through evaporation, thus forming sait deposits. The alternate active and stable tectonic periods made up favorable tectonic conditions for salt-deposition. Due attention should also be paid to some unfavorable factors, such as the periodical desalination of basin water in the process of salt-deposition, the development of numerous fractures in basins, and the deep burial of salt-bearing sequences. Nevertheless, the search for potash deposits in this region is On the whole of brilliant prospect. |
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