STUDY ON THE PORPHYRY DEPOSIT SYSTEM

In regional scale, porphyry copper systems have the following characteristics: 1) commonly occurring in belts, with deposits either as clusters or structurally controlled alignments; 2) mainly generated in island arc and continental margin environments, related to compressive or moderate extensional stress; 3) initiated by the invasion of oxidative Ssaturated and metal-rich magma, which provides ore-forming materials; and 4) with the size, grade and type of mineralization strongly influenced by the physical properties and chemical compositions of the host rocks. The depositscale characteristics of porphyry copper systems are as follows: 1) There is a close spatial-temporal and genesis relationship between porphyry copper deposit and porphyry stocks; 2) The volcanic breccia pipes either cut or occur alongside the porphyry copper mineralization in the deep, commonly with high-sulfidation Au mineralization contact zones; 3) The ore-related breccias in the ore-forming system include explosive breccia, intrusive breccia, explosiveintrusion breccia, hydrothermal breccias and hydrothermal pebble veins; 4) From bottom to top, the hydrothermal alterations are in the zonation of early barren sodic-calcic, ore-bearing potassic, chloritization-sericitization, sericitization and advanced argillic alteration; And 5) the lithocap, which is an important indicator for exploration, is a significant component of the hydrothermal-mineralization-alteration system in porphyry copper system.