摘要
探讨多硅白云母地质压力计在低温退变质过程中的稳定性,在对大别山东缘和苏鲁造山带西缘郯庐左旋走滑韧性剪切带糜棱岩中的多硅白云母残斑由中心向两侧边缘进行电子探针分析后发现:由中心向两侧边缘Si减少,Al增加,Fe,Mg略有降低,部分样品中K,Na有不同程度的增加,而Ti则显示不活动富集。这是由于退变质过程中流体的活动常会改变残斑白云母的成分,并且在流体活动过程相对短暂的情况下,使残斑白云母的成分不能发生充分变化,最终会导致白云母不同部位具有不同的成分。因而,经历了富流体活动的退变质作用后,岩石中的多硅白云母残斑已不能完全保存其形成时的压力信息。
For the purpose of studying the stability of phengites geobarometry in retrograde metamorphism.The porphyroclast muscovites in Tanlu ductile shear zone,eastern Dabie Mountains and western Sulu Mountains were analyzed by electron microprobe from the centre to the rim on the grains. The result showed that from center of porphyroclast muscovites to rim,Si,Fe,Mg decreases,Al,K,Na increases,and Ti is enriched,which were caused by the composition change of muscovite in retrograde metamorphism.When the process of metamorphism is short,composition of porphyroclast muscovite can only partly be changed,resulting in the variation of composition in the different domains of porphyroclasts.Therefore,it was difficult for the porphyroclast muscovite to reserve the information of paleo-pressure after the retrograde metamorphism.
出处
《矿物岩石》
CAS
CSCD
北大核心
2004年第4期20-27,共8页
Mineralogy and Petrology
基金
国家自然科学基金资助项目(编号:40272094)
