摘要
小黑山岩体位于辽东半岛南部，由变形的闪长岩、花岗闪长岩、花岗岩组成。锆石LA—ICPMSU—Pb年代学研究表明，上述三类岩石的侵位时代分别为170～174Ma、174±1Ma和177±2Ma；后期花岗质伟晶岩脉的侵位时代为175±1Ma。这些年龄在误差范围内基本相同，反映了小黑山岩体是一个侏罗纪侵位的杂岩体。岩石地球化学、Sr—Nd同位素和锆石铪同位素组成研究表明，小黑山岩体主要来源于高压下古老下地壳物质的部分熔融，慢源岩浆不仅为地壳物质的部分熔融作用提供了热量，而且直接参与了花岗岩的成岩作用。结合区域地质资料表明，小黑山岩体乃至华北东部侏罗纪花岗质岩浆作用是古太平洋板块向西俯冲、地壳增厚，进而引发下地壳物质部分熔融的结果。
The Xiaoheishan pluton is located in the southern Liaodong Peninsula of the eastern North China Craton, and consists of deformed diorite, granodiorite and biotite granite. LA-ICPMS zircon U-Pb dating gives the age of 174-170 Ma for diorite, 174±1 Ma for granodiorite, 177±2 Ma for biotite granite and 175±2 Ma for granitic pegmatitic dike, indicating that the Xiaoheishan pluton is a Jurassic intrusive complex. Geochemical, whole rock Sr and Nd isotopic and zircon Hf isotopic data indicate that the diorite, granodiorite and granite of the Xiaoheishan pluton were result of partial melting of ancient lower crustal materials at high pressures, interacted with mantle-derived magmas. The Xiaoheishan pluton and the Jurassic magmatism in the eastern North China Craton formed in a continental crustal thickening setting that may be related to subduction of the Paleo-Pacific oceanic plate, which induced partial melting of lower crustal materials of the North China Craton.
出处
《矿物岩石地球化学通报》
CAS
CSCD
2007年第1期29-43,共15页
Bulletin of Mineralogy, Petrology and Geochemistry
基金
国家自然科学基金资助项目(40672055
40325006)
大陆动力学国家重点实验室基金资助项目
