苏北原生金刚石找矿现存问题探讨

The discussion of primary diamonds exploration in Northern Jiangsu Province

苏北第二轮金刚石找矿历时8 a,尚未发现含矿的金伯利岩或金刚石矿床。从苏北找矿实际出发,结合最新的金刚石成矿理论和进展,提出和探讨了制约苏北原生金刚石找矿的几个问题,进一步探讨了找矿方向。研究认为:苏北原生金刚石找矿的首要目标为古生代金伯利岩,在郯庐断裂带西侧,由于徐宿弧形构造的存在,可能使得该期金伯利岩被掩盖于推覆体之下;郯庐断裂带与古生代金伯利岩没有成因联系,但其在伸展阶段控制发育的断陷红盆,可能使得带内的古生代金伯利岩被掩盖在白垩系之下。今后的找矿方向应重点集中在郯庐断裂带内的城岗隆起上,郯庐断裂带西侧的含角砾基性岩亦是值得关注的对象。在开展找矿勘查时,应充分考虑工作区地质与地形条件、方法适应性和局限性等因素,因地制宜选择勘查方法组合。

The second round of diamond prospecting in Northern Jiangsu Province has lasted 8 years,without discovery of ore-bearing kimberlite or diamond deposits.Based on the actual prospecting in Northern Jiangsu and combined with the latest diamond ore-forming theory and advance,the authors in this paper put forward and discuss several issues restricting the prospecting of primary diamonds in Northern Jiangsu to further explore the prospecting direction.The results show the primary target of primary diamond prospecting in Northern Jiangsu Province is Paleozoic kimberlite,which is located in Western Tanlu fault zone.The kimberlite of this period may be covered under the nappe due to the existence of the Xusu arc structure.Although there is no genetic relationship between Tanlu fault zone and Paleozoic kimberlite rock,the rifted red basin controlled by its development in the extension stage may cause the Paleozoic kimberlite to be covered under the Cretaceous.The future prospecting direction should focus on the Chenggang uplift in the Tan-Lu fault zone,and the breccia-bearing basic rocks on the west side of the Tanlu fault zone are also worthy of attention.During the ore prospecting and exploration,the geological and topographical conditions of the work area,the adaptability and limitations should be fully considered to select the combination of exploration methods according to local conditions.