Earth Science Frontiers ›› 2018, Vol. 25 ›› Issue (6): 20-41.DOI: 10.13745/j.esf.sf.2018.11.19

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Isotopic mapping and deep material probing (Ⅱ):imaging crustal architecture and its control on mineral systems.

HOU Zengqian,WANG Tao   

  1. 1. Key Laboratory of the Deep Earth Geodynamics, Ministry of Natural Resources, Beijing 100037, China
    2. Beijing SHRIMP Center, Beijing 100037, China
    3. Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China
  • Received:2018-10-10 Revised:2018-11-09 Online:2018-11-30 Published:2018-11-30

Abstract: The deep Earth is the “engine”, “supply source” and “transfer belt” for large-scale mineralization. The mineralization process, therefore, is best understood by revealing deep material composition and distribution, deep material cycle and energy conversion, and deep crustal three-dimensional structure and dynamic process. Magmatic rock “probe”, or lithoprobe, and regional isotopic mapping (such as whole rock Nd and in situ zircon Hf isotope) are the main techniques used for exploring compositional and evolutionary processes of deep Earth. These probing techniques can detect deep crustal composition and three-dimensional architecture to reveal the spatial distribution and temporal evolution of the new, old and recycled crust, providing deep Earth constrains on regional metallogenic regularity to assist quantitative and semi-quantitative evaluation of metallogenic potential and improve regional prediction model. Here, we examined magmatic whole-rock Nd and zircon Hf isotopic mapping in solving deep crustal three-dimensional structure and its control on metallogenesis, and discussed the developmental mechanism of massive magmatic rock deep inside Earth and its metallogenic constraints. We also examined the deep crustal architecture and its control on mineralization of different-types of orogens (e.g., the Central Asian accretionary orogenic belt, the Qinghai-Tibet plateau collisional orogen and the Qinling composite orogen) and several cratons. The results show that the distribution of copper, gold, copper and nickel deposits is controlled by the distribution of juvenile crust independent of orogenic belt and craton types. They also show that large-scale molybdenum and lead-zinc ores as well as rare metals and other minerals occur in old crust, and iron ores often developed in the transition zone between the old and new crust. In addition to revealing the regional metallogenic rules, our findings may applicable in metallogenic prediction and metallogenic potential evaluation, an expected new direction for studying regional metallogenic regularity including especially studies of detection and metallogenic background of deep crustal material.

Key words:  lithoprobe, isotopic mapping, deep material composition, three-dimensional structure, regional metallogenesis

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