The ‘Jiaodong type’ gold deposits: Characteristics, origin and prospecting

Abstract

The Jiaodong type comprises a unique class of gold mineralisation which includes the Linglong type quartz-vein hosted and the Jiaojia type fracture-disseminated style deposits. Although the type area is in the Jiaodong Peninsula in NE China, where some of the world's richest gold reserves occur, we identify similar occurrences in other parts of China and elsewhere in the world under this category. The ore fluids migrated upwards forming quartz vein type of gold ore (Linglong type) wherever the ore-controlling fractures are at high angles. Fluid infiltration into the surrounding wall rocks and generation of the Jiaojia type disseminated style deposits resulted where the ore-bearing fluids encountered low angle fractures. On a regional scale, the Jiaodong type gold mineralisation occurs along the margins of reactivated cratons, within the interior of cratons along paleosuture zones, or along the junctions of micro-blocks, and is distinctly different from the classic orogenic gold in terms of their tectonic setting, ore characteristics and genetic history. Unlike skarn and porphyry type of deposits, the Jiaodong type gold deposits do not always show close spatial relationship with magmatic intrusives and some of the deposits occur distal to plutons (>10km). In this paper, we evaluate the salient geological, geochronological, geochemical and isotopic features of the Jiaodong type gold deposits and propose some general guidelines for gold prospecting. Based on case studies, we predict that the gold lodes in the Jiaodong type mineralised zones might extent vertically up to 3000m with only minor mineralogical and geochemical variations.