摘要
虎子岩碱性橄榄玄武岩具有与大陆裂谷玄武岩相似的地球化学特征。通过对岩体及其尖晶石二辉橄榄岩包体地球化学特征的研究,揭示了本区地幔在先期亏损的基础上又迭加了一次交代事件,虎子岩基性岩浆是由交代地幔约16％的低程度部分熔融的产物。用辉石温压计估算出,包体矿物的平衡结晶温度为1038—1109℃,压力为22—25×10~8 Pa,推测包体来源深度为72—85km。岩体形成可能是受郯庐断裂南延带拉张(裂谷)阶段控制。
Huziyan alkali-olivine basalt is of similar geochemical feature to those of continental rift. Geochemical studies on the rock mass and its spinel lherzolite xenolith indicate that the mantle in this region has experienced metasomatism after the previous depletion. Huziyan basalt is derived from partial melting of the metasomatized mantle to a degree of about 16%. The equilibrium crystalization temperature and pressure of the minerals in the xenolith are calculated using J-C.C.,Mercier＇s single-pyroxene geothermometry and geobarometry to be 1038--1109℃ and 22--25×10~8Pa seperately, which suggests that the xenolith was brought up from 72--85km depth. Huziyan basalt is assumed to be controlled by the southern elongation of Tancheng-Lujiang fault at the extension stage.
出处
《湖南地质》
1991年第1期52-58,共7页
Hunan Geology
关键词
基性岩
岩体
包裹体
地球化学
Basalt and Xenolith
Geochemistry
Mantle-metasomatism
Southern elongation of Tancheng-Lujiang fault
