新生代构造抬升与斑岩型铜、金矿床的次生富集作用

以中国西南"三江"(澜沧江-金沙江-怒江)地区西范坪铜矿床、玉龙铜矿床和北衙金矿床为例说明了该地区斑岩型铜或金矿床的次生分带特征,概述了青藏高原、滇川西部高原的隆升,以及新生代构造抬升对地表化学风化的影响;指出西范坪铜矿床、玉龙铜矿床和北衙金矿床等明显经历过表生成矿作用的典型斑岩型矿床均位于青藏高原强烈隆升区的边部或边缘地带,新生代构造抬升对这些地段气候、地形的影响大大促进了地表的化学风化作用;认为新生代强烈隆升可能是导致这些矿床发生强烈次生富集作用的深层次原因.

Cenozoic Tectonic Uplifting and Secondary Enrichment of Porphyry Copper and Gold Deposits

Most of the porphyry copper or gold deposits in "Three River"(i. e. Lanchangjiang,Nujiang,and Jingshajiang rivers) area,southwestern China,underwent intensive oxidation,forming a thick secondary enrichment zone,where ore grade is greatly elevated. The enrichment for metallogenetic element and changes in structure of ore owing to supergenesis are in great favor of mining and ore cleaning. Thus the ore in secondary enrichment zone is the main part for mining. This paper takes Xifanping copper deposit, Yulong copper deposit and Beiya gold deposit as an example to illustrate the oxidation zoning of the porphyry copper or gold deposit in "Three River" area, and also summarizes the uplifting problem of Tibet Plateau and Western Dianchuan (Yunnan and Sichuan) Plateau,as well as effects of the Cenozoic tectonic uplift on the earth surface chemical weathering. It is emphasized that the typical representatives of deposits undertaking intensive supergenesis in "Three River" area are all located in or to the margin of Tibet Plateau,where the Tibet Plateau uplift has the strongest effect on the climate and landform,and thus the earth surface chemical weathering. Therefore,it can be concluded that the Cenozoic tectonic uplift is the underlying reason for the intensive supergenesis of the deposits.