Control Significance of Geological Surface for Pb-Zn Ore Deposits in Guizhong Depression
-
摘要: 桂中凹陷大地构造条件特殊, 其北为桂北台隆, 与扬子地台接壤, 其西与右江再生地槽连接, 其东和南与大瑶山隆起相连.在区域性范围内, 广西大部分铅锌矿床分布于桂中凹陷的边缘.其中, 河池-南丹成矿带几十个大-中型和特大型铅锌铜矿床位于凹陷的西部及西北部边缘, 在凹陷的东南部和东部边缘有武宣-象州成矿带的几十个大-中型和特大型铅锌铜矿床, 在凹陷的南、北和东南、东北部边缘地带则连续分布着宾阳、贵县、锡基坑、北山、泗顶等若干个大-中型铅锌铜矿床.在矿区范围内, 铅锌矿体主要产于不整合面附近、多组断裂的交汇部位、岩体的周围、沉积岩相变带、不同岩性接触面等.不论在宏观的区域范围内, 还是在微观的矿区范围内, 矿床的成矿作用和分布明显受到地质界面的控制, 其主要特征与美国MVT铅锌矿床相似.地质界面是地球内部能量集中、汇集、传递、转化和释放的地带, 是地球物质变化、活化、迁移和沉淀富集的部位, 也是成矿作用发生的场所.桂中凹陷与周边地质构造单元接合处的地质界面是“ MVT型”铅锌矿床形成的有利地段.Abstract: The Guizhong depression with special geotectology conditions is bounded on the north by the Guibei antiklise and the Yangtze platform, on the west by the Youjiang regenerated geosyncline, and on the east and the south by the Dayaoshan rise. In the region, most of the Pb-Zn deposits in Guangxi Zhuang Autonomous Region are distributed around the Guizhong depression. The ultralarge scale and large-moderate scale Pb-Zn ore deposits of the Hechi-Nandan metallogenetic belt lie on the boundary of the west and the northwest of the depression, the deposits of the Wuxuan-Xiangzhou metallogenetic belt lie on the boundary of the east and the southeast of the depression, and many deposits such as Binyang, Guixian, Xijikeng, Beishan and Siding lie on the boundary of the south, the north, and the northeast. In the ore district, the occurrences of the orebodies are controlled principally by different geological surfaces like the plane of unconformity, the contact of some faults, the periphery of magmatic rock, the site of sedimentary facies change, and the contact areas of diverse lithofacies. Whether within the region or within the ore district, the mineralization and distribution of Pb-Zn deposits are evidently controlled by the geological surfaces. The characteristics demonstrate that Pb-Zn deposits around the Guizhong depression are very similar to the MVT Pb-Zn deposits in the Mississippi Valley, USA(MVT). The various geological surfaces are the district of the transmission, concentration, conversion and release of energy within the earth, and are the place of the change, the activation, the transportation and the precipitation of the materials of the earth, and are the locale of the mineralization. The geological surfaces in the joint of the Guizhong depression with the peripheral geological structure units are the favorable districts of the mineralization of the MVT type lead-zinc deposits.
-
图 1 广西桂中凹陷地区铅锌矿床分布示意(据广西壮族自治区地质矿产局(1985)、广西铅锌矿地质(2001)内部资料改编)
1.省界线; 2.地区界线; 3.铁路; 4.公路; 5.城镇; 6.矿山; 7.大地构造分区; 8.大、中、小型铅锌矿床; A.桂北台隆; B.桂中凹陷; C.大瑶山隆起; D.右江再生地槽
Fig. 1. Sketch of distribution of the Pb-Zn deposits in the Guizhong depression of Guangxi
图 2 大新长屯铅锌矿床白缘山矿段剖面(据广西壮族自治区地质矿产局(1985)、广西铅锌矿地质(2001)内部资料改编)
1.第四系; 2.中泥盆统; 3.下泥盆统郁江组、四排组(未分层); 4.下泥盆统莲花山组、那高岭组(未分层); 5.下泥盆统莲花山组; 6.寒武系上统; 7.断层及编号; 8.平移断层; 9.矿体; 10.钻孔及编号
Fig. 2. Profile of the Baiyuanshan district of the Daxin Zhangtun Pb-Zn deposit of Guangxi
图 3 河池拉么(铅) 锌铜矿床剖面(据广西壮族自治区地质矿产局(1985)、广西铅锌矿地质(2001)内部资料改编)
1.同车江组泥灰岩; 2.同车江组炭质页岩; 3.同车江组灰岩; 4.五指山组小扁豆状灰岩; 5.五指山组细条带状硅质灰岩; 6.五指山组宽条带状灰岩、泥灰岩; 7.榴江组硅质岩; 8.中泥盆统泥灰岩; 9.似层状矿体及编号; 10.细脉带矿体及编号; 11.花岗岩
Fig. 3. Profile of the Hechi Lame (Pb)-Zn-Cu deposit of Guangxi
图 4 广西新华铅锌银矿床地质图(据广西壮族自治区地质矿产局(1985)、广西铅锌矿地质(2001)内部资料改编)
1.海西期中-细粒堇青石黑云母花岗岩; 2.海西期中-粗粒堇青石黑云母花岗岩; 3.断层及编号; 4.岩相界线
Fig. 4. Geological map of the Xinhua Pb-Zn-Ag deposit of Guangxi
图 5 广西泗顶铅锌矿床28线K1-K4钻孔剖面(据广西壮族自治区地质矿产局(1985)、广西铅锌矿地质(2001)内部资料改编)
1.融县组第一至三段; 2.下寒武统清溪组; 3.砂页岩; 4.灰岩; 5.白云岩; 6.白云岩化带; 7.断层; 8.铅锌矿体; 9.不整合面
Fig. 5. Profile of the 28th prospect line of the Siding Pb-Zn deposit of Guangxi
-
[1] Barnes, H.L., 1997. Geochemistry of hydrothermal ore deposits. Third Edition. John Wiley & Sons Inc., New York. [2] Bureau of Geology and Mineral Resources of Guangxi Zhuang Autonomous Region, 1985. Regional geology of Guangxi Zhuang Autonomous Region. Geological Publishing House, Beijing(in Chinese). [3] Duan, S.D., Tan, Y.L., 1990. Surface chemistry. Higher Education Press, Beijing(in Chinese). [4] Li, K. Y., 1998. Surface and physicochemistry of colloid. Harbin Institute of Technology Press, Harbin, China (in Chinese). [5] Li, L.H., Zhang, B.A., 1984. Physicochemistry. Higher Education Press, Beijing(in Chinese). [6] Sicree, A.A., Barnes, H.L., 1996. Upper Mississippi Valley district ore fluid model. The Role of Organic Complexes, 11: 105-131. [7] Sverjensky, D.A., 1989. The diverse origins of Mississippi Valley-type Zn-Pb-Ba-F deposits. Chron. Rech. Min. , 495: 5-13. [8] Zhai, Y.S., Zhang, C., Song, H.L., et al., 1997. Large-scale structures and ultralarge-scale ore deposits. Geological Publishing House, Beijing(in Chinese). [9] 段世铎, 谭逸玲, 1990. 界面化学. 北京: 高等教育出版社. [10] 广西壮族自治区地质矿产局, 1985. 广西区域地质志. 北京: 地质出版社. [11] 李葵英, 1998. 界面与胶体的物理化学. 哈尔滨: 哈尔滨工业大学出版社. [12] 李吕辉, 张报安, 1984. 物理化学. 北京: 高等教育出版社. [13] 翟裕生, 张潮, 宋鸿林, 等, 1997. 大型构造与超大型矿床. 北京: 地质出版社.