东秦岭中生代花岗岩体、钼矿床分布的时空规律及其动力来源

Spatio-temporal Distributions of Mesozoic Granite Plutons and Molybdenum Deposits in East Qinling and Their Dynamic Implication

以地壳运动的4种力源为理论指导,通过对东秦岭花岗岩体、钼矿床空间分布与其形成年龄的系统研究,总结发现成岩、成矿的时空分布规律。结果表明：三宝断裂南侧的花岗岩体年龄从西向东逐渐变老;栾川断裂两侧分布的花岗岩体年龄从西向东逐渐变新;根据钼矿床与花岗岩体的空间关系,东秦岭钼矿可以划分为老牛山、蟒岭、石宝沟、花山和合峪等5个矿集区,从北东向南西,其成岩、成矿年龄逐渐变新。矿体与花岗斑岩的时间关系是：花岗斑岩侵入早,成矿热液向上运移晚,相差2.8-17 Ma。花岗岩成岩、成矿时空分布规律的地球动力学机制为：地球的内外差自转使岩石圈向西漂移,形成栾川断裂两侧花岗岩年龄西边老、东边新的现象;大陆向北漂移的动力使各个矿集区成岩、成矿年龄呈北东老、南西新的分布;较差自转的扭动力使控矿断裂呈北东—南西向分布;地壳垂直运动的力源使东秦岭成岩、成矿发生在东西向断裂与北东向断裂交会的节点上。

According to the theory of four power sources in crustal movement, the spatial distribution and formation ages of granite plutons and molybdenum deposits in East Qinling were studied, and the spatio-temporal distributions of diagenesis and mineralization were summarized. The results show that the ages of granite plutons in the south side of Sanbao fault are gradually older from west to east; the ages of granite plutons located on the sides of Luanchuan fault are gradually younger from west to east; according to the spatial relationship between granite plutons and molybdenum deposits, the molybdenum deposits can be divided into five ore concentration areas including Laoniushan, Mangling, Shibaogou, Huashan and Heyu, and the formation ages of diagenesis and mineralization are gradually younger from northeast to southwest. The temporal relationships between orebody and granite porphyry include that granite porphyry intrusion is 2.8-17 Ma earlier than metallogenic hydrotherm upward migration. The geodynamic mechanism of spatio-temporal distributions of granite diagenesis and mineralization in East Qinling can be explained by the internal and external differentia rotation of earth. The differentia rotation causes that the lithosphere drifts westward, and then the formation ages of granite plutons on the sides of Luanchuan fault are younger from west to east; the power of continental drifting northward causes that the formation ages of diagenesis and mineralization in ore concentration areas are older in the northeast than that in the southwest; the distribution of ore controlling fault is NE-SW direction because of the twisting force from poor rotation; the power of earth crust vertical movement makes that the diagenesis and mineralization occur in the intersecting place where the northeast and southwest striking faults joint.