摘要
金伯利岩成因是国内外许多学者一直探讨的课题.笔者通过对辽东半岛南部金伯利岩的研究表明:金伯利岩岩浆的形成是包括熔融作用在内的多种地质作用的综合结果.控制金伯利岩岩浆形成的主体作用是地幔(这种地幔具亏损和富集地幔的双重特征)的部分熔融,对于含矿性越贫的岩体,其金伯利岩岩浆就存在越强烈的结晶分离作用和地幔易熔组分的萃取作用.金伯利岩岩浆形成的深度可以通过金伯利岩中最高Cr_2O_3含量的石榴石,按照关系式p(GPa)=0.32612Cr_2O_3((?),%)+0.9278(r=0.9958)来估算.本文把岩浆温度、氧逸度、粘度、密度、上升速度及裂隙宽度的估算引入金伯利岩.金伯利岩浆是按底辟—裂隙模式形成和上侵的.
The petrogenesis of kimberlite has long been a research project.My study shows that kimberlite magmas are generated by the partial melting of the mantle, which is characterized by both deleption of fusible major elements and enrichment of incompatible trace elements. There have been stronger fractional crystallization and extraction of incompatible elemets in mineral-poor kimberlite. The pressure at which kimberlite magmas are formed can be calculated from the most Cr2O3-rich pyrope. The formula is p(GPa)=0 .32612 Cr2O3(wB. %)+0.92778 (r=0.9958).Furthermore, calculations of magma temperature, oxygen fugacity, viscocity, density, uprising velocity and the creak width are also introduced in this paper.The magmatism physics is fasioned after diapir-creak model.
出处
《地质科技情报》
CAS
CSCD
北大核心
1989年第2期8-14,共7页
Geological Science and Technology Information
