摘要
本文论述了中国北方(包括华北、东北及长江中下游地区)金属矿床的空间分布特点,分析和讨论了主要成矿区带(长江中下游、小秦岭-熊耳山、西秦岭、华北克拉通北缘和大兴安岭南段)及一些大型矿集区(胶东、鲁西和乌奴格吐-甲乌拉)中矿化组合和成矿期次以及地球动力学背景。提出中国北方大规模成矿作用出现在200-160Ma,140Ma左右和120Ma左右三个峰期。通过对中生代地球动力学演化的分析研究,认为三大成矿事件所对应的地球动力学背景分别为后碰撞造山过程、构造体制大转折晚期和岩石圈大规模快速减薄。在200-160Ma时期主要表现为大厚度岩石圈局部伸展有关的岩浆-热成矿,在140Ma左右时期成矿表现为与深源花岗质岩石有关的斑岩-夕卡岩矿床,而120Ma左右时期的成矿是在岩石圈快速减薄过程有大量地幔流体参与成矿作用。
We describe the temporal-spatial distribution of the main Mesozoic metallogenic belts and regions in North China, comprising the Middle Lower Yangtze River valley, the Xiaoqinling-Xiong'ershan (eastern Qinling) and western Qinling, North margin of the North China craton, and southern part of the Daxing'anling as well as the eastern Shandong peninsular and Wulugetu-Jiawula (Manzhuli). After collecting and documenting the precise radiometric age data of the ore deposits there appear three metallogenic pulses, i. e. 190 similar to 160 Ma, ca. 140 Ma, and ca. 120 Ma. Almost all the gold only depoists in eastern Shandong peninsular formed at time of ca. 120 Ma. It is obvious there are two pulses of mineralization at ca. 140 Ma and ca. 120 Ma in the Middle Lower Yangtze River valley, and Xiaoqinling-Xiong'ershan region, where the porphyry-skarn-manto Cu-Au-Mo-Fe and Mo-(W) deposits occurred at the age of ca. 140 Ma whereas the gold deposits and terrestrial volcanic rock related iron deposits appeared at age of ca. 120 Ma. The Mesozoic mineralization in the northern margin of the North China craton developed in three pulses and their ages are getting older from the eastern margin of the Euroasian continent inward. The gold deposits in the western Qinling are dated to be an age range of 190 similar to 160 Ma. In southern part of the Daxing'anling the granite-related Cu-Ag and Pb-Zn-Cu deposits are ca. 160 similar to 177 Ma, granite-related Sn-Cu-Pb-Zn and Sn deposits are ca. 140 Ma, and Nb-Y-Zr deposit is 127 Ma. Based on the study of Mesozoic tectonic evolution, we propose these three pulses of large-scale mineralization are the consequences of the postcollisional process of the Triassic convergence between the northern China craton and the Yangtze craton, late stage of the tectonic regime changing its main stress from NS-trending to EW-trending, and lithosphere thinning process, repectively. The gold deposits associated with S-type granite of 200 similar to 160Ma develop in the extension setting of postcollisional stage. At ca. 140 Ma a great amount of I-type granite porphyry derived from the upper mantle and lower crust empleaced at the shllow crust and are accompanied by porphyry-skarn-(manto) Cu-Mo-Fe-Au and Mo-W mineralization. Due to lithosphere rapid thinning at ca. 120 Ma the asthenosphere got into the curst, which gave up to the mixed fluids from the mantle, metamorphic process, and crust to leach the metallic elements so as to form the gold ore-forming system as well as the iron deposit association related to terrestrial volcanic activity.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2005年第1期169-188,共20页
Acta Petrologica Sinica
基金
本文为国家重点基础研究发展规划项目(编写:G1999043211和G1999043216)地质调查项目(K1.4)国家自然科学基金委员会重点基金项目(编号:40434011)的成果
