THE RELATIONSHIP BETWEEN METALLOGENY, MAGMATISM AND STRUCTURE IN JIANGXI PROVINCE, A NEW INTERPRETATION

Granite magmatism and the associated metallogeny for which Jiangxi Pro- vince is renowned are considered in relation to a plate tectonic model which envisages the suturing of three separate continental fault blocks or plates which are thought to have existed as separate continental plates until the Permian, namely the Sino-Korean, Yangtse and South China Plates. This was followed by the cratonisation of the continental landmass of south- eastem China and the developmemt of the southeastern plate margins of the new continent in the circum-Pacific zone. The post-suture magmatic intrusions were emplaced during tbe cratonising event ard their magma type and associated ore deposits are shown to vary sys- tematcally in relation to destructive plate margi ns which are thouht to have formed along all the plate boundaries between the continental plates. The granitic intrusions range from more proximal porphyires of Cu, Cu-Mo and W-Cu type to more distal granites of W-Sn-F-U-Nb-REE type. All of these intrusions, which are strongly discordant, have well developed thermal aureoles and range in age from Indosinian to Yanshanian （but mainly the latter）, were intruded along major lithospheric fracture zones, with sinistral strike slip. These metallogenic granites, which were all intruded postectonically or after the suturing events, are considered to be essentially of juvenile magmatic ori- gin. Such a model helps to account for the well developed metallogeny of Jiang- xi Province which yields Cu （Mo-W） porphyries distrubuted along both the Limits and South China plates. Four such zones maybe distinguished within the boundaries of the province. More distally from the destrucive margins W-Sn-F （U-Nb-REE） granites are intruded in the central zones of both plates, and these are also associated with major ore deposits, espeoially where the granites are intruded into lower Palaeozoic low-grade metamorphic basement which provided abundant fluids for hydrothermal circulation systems. The Sino-Korean-Yangtse-South China Plate boundaries are therefore es- sentially of Andean type and they can also be closely compared with those pre- viously proposed to account for the magmatism and metallogeny of the British Caledonides by Simpson et al, Plant et al and British Hercynides by Watson. Fowler and Simpson.