华夏地块东部德化早古生代镁铁质-长英质侵入岩的成因及其地质意义

Recently, the granite with very high ε Hf (t) values (up to 10.3 ), ~ 495 Ma magmatic rock and Dehua gabbro-diorite-quartz diorite-granodiorite assemblage have been found on the east of the Pucheng-Wuping fault by the research of the Paleozoic ignous rocks in South China, which are completely distinctive from the granite assemblage widely distributed on the west of the Pucheng-Wuping fault, with lowε Hf (t) values (<0) and yonger age ( from ~ 465 to 400 Ma). Dehua gabbro-diorite-quartz diorite-granodiorite which were the only pre-Yanshanian mafic-felsic plutons in the eastern Cathaysia has great significance in defining the property and evolution of mantle source beneath the eastern Cathaysia. Study of geological investigation, petrology, geochemistry, Zircon U-Pb dating and Hf isotope will be execute on the Dehua gabbro-diorite-quartz diorite-granodiorite assemblage in the eastern Cathaysia Block, which restricting its special and temporal distribution, petrogenesis, the property of mantle source, and further understanding the geodynamics of the early Paleozoic magmatism by compared with other Paleozoic igneous rocks in South China.

近来，在对华南早古生代岩浆岩的研究中，于浦城-武平断裂带以东发现了~ 495 Ma的岩浆活动、具有相当高的锆石ε Hf (t)值（可高达10.3）的花岗岩以及德化辉长岩-闪长岩-石英闪长岩-花岗闪长岩组合，这与该断裂带以西广泛发育的ε Hf (t) < 0的~ 465-400 Ma花岗岩组合差异显著。德化辉长岩-闪长岩-石英闪长岩-花岗闪长岩是目前华夏地块东部发现的唯一的前燕山期镁铁质-长英质岩组合，是限定华夏地块东部早古生代地幔属性及其演化的唯一资料。本项目拟通过对德化辉长岩-闪长岩-石英闪长岩-花岗闪长岩这一岩石组合的野外产状、岩石学、地球化学、锆石U-Pb年代学及Hf同位素等多方面的综合研究，查明德化侵入岩的时空分布和岩石成因，厘定华夏地块东部地幔源区属性，并通过与邻区岩浆岩的对比，深化对华南早古生代岩浆作用及其地球动力学机制的认识。