成矿系统的多尺度探测：概念与进展——以长江中下游成矿带为例

Multi-scale exploration of mineral system: Concept and progress——A case study in the middle and lower reaches of the Yangtze River Metallogenic Belt

在全球矿产勘查逐渐转向"绿地"、深部和覆盖区的大背景下,急需成矿理论的指导。20世纪末提出的成矿系统概念由于其强大的区域成矿预测功能,引起了矿业界广泛的关注和研究。本文首先回顾了成矿系统的概念、组成和分类,然后讨论了成矿系统主要组成部分的探测和识别方法,最后结合笔者近年在长江中下游成矿带开展的多尺度探测,讨论了陆内典型成矿系统的深部过程、地壳结构和地球物理响应,并对成矿系统概念在成矿预测领域的应用前景进行了展望。本文主要结论:(1)成矿系统是由控制矿床形成和保存所有要素构成的自然系统,基本组成单元包括"源区"、"通道"和"场所",每个组成单元都包括复杂的物理、化学和动力学过程;(2)矿床是成矿系统多尺度深部过程耦合在某一"点上"的"结果"。成矿系统在演化过程中,各种物理、化学作用对地壳和岩石圈地幔进行了强烈"改造",留下各种物理、化学和矿物学"痕迹",这些"痕迹"改变了岩石的地球物理性质,具有很好的可探测性;(3)基于长江中下游多尺度探测结果,提出了陆内典型成矿系统"源区"形成过程、控制岩浆/流体迁移的"通道"和物质沉淀场所的新认识;(4)在地学大数据、机器学习、人工智能不断发展的今天,成矿系统和基于成矿系统的多尺度成矿预测将是未来的重要研究方向。

The guidance of metallogenic theory is urgently needed under the background that global mineral exploration is gradually turning to the target at "greenfields", deep earth and coverage areas. The concept of metallogenic system proposed at the end of the last century has attracted extensive attention and study of the mining industry due to its powerful function of regional mineralization forecasting. In this study, first and foremost, the authors review the concept, components and classification of mineral systems. Then the methods of detecting and identifying the main components of the metallogenic system are discussed. Last but not least, the deep process, crustal structure and geophysical response of typical intracontinental metallogenic systems are discussed based on the authors’ multi-scale exploration in the middle and lower reaches of the Yangtze River Metallogenic Belt in recent years, and the application of the concept of mineral system in the field of metallogenic prediction is also prospected. The main conclusions of this paper are as follows:(1) The mineral system is a natural system that comprises all the essential factors controlling the formation and preservation of deposits, with basic components of"source","path"and"site". Each component includes complex physical,chemical and kinetic processes.(2) A deposit is the‘result’of multi-scale deep processes coupling at a certain‘point’in the mineral system. During the evolution of the mineral system, various physical and chemical processes have strongly"modified"the crust and lithospheric mantle, leaving behind various physical, chemical, and mineralogical "footprints" with significant detectability due to the altered geophysical properties.(3) A new model was proposed based on the multi-scale exploration in the middle and lower reaches of the Yangtze River Metallogenic Belt, for the understanding of"source","path"and"site"of a typical intracontinentalmetallogenic system.(4) Mineral system based multi-scale target predication will be a prospective research direction in the future, with the continuous developing of geoscience big data, machine learning and artificial intelligence.