CAJ | 학술논문

在南太行山平顺闪长岩体中偶见具有特殊环带结构的斜长石，其核部为钙含量高的基性斜长石（An＞63），幔部为富钠的斜长石，二者之间存在由绢云母和绿帘石组成的溶蚀带，且核、幔 An 值变化截然不同。根据斜长石的环带构造特征和成分分析，认为本区岩浆混合过程大致如下：起源于 EMI 型富集地幔的幔源岩浆底侵作用于下地壳，在高温下结晶出钙含量高的基性斜长石，且所携带的热使下地壳开始熔融形成壳源岩浆；壳、幔两种岩浆沿着太行山深大断裂快速上升侵位于地壳浅部，发生岩浆混合；与此同时，早期形成的基性斜长石由于压力突然减小发生溶蚀，形成形态不规则的溶蚀带；壳幔混合岩浆在基性斜长石基础上结晶生长富钠斜长石，形成具有特殊环带结构的斜长石。这为研究区内存在岩浆混合作用提供了最直接的证据。
재남태행산평순섬장암체중우견구유특수배대결구적사장석，기핵부위개함량고적기성사장석（An＞63），만부위부납적사장석，이자지간존재유견운모화록렴석조성적용식대，차핵、만 An 치변화절연불동。근거사장석적배대구조특정화성분분석，인위본구암장혼합과정대치여하：기원우 EMI 형부집지만적만원암장저침작용우하지각，재고온하결정출개함량고적기성사장석，차소휴대적열사하지각개시용융형성각원암장；각、만량충암장연착태행산심대단렬쾌속상승침위우지각천부，발생암장혼합；여차동시，조기형성적기성사장석유우압력돌연감소발생용식，형성형태불규칙적용식대；각만혼합암장재기성사장석기출상결정생장부납사장석，형성구유특수배대결구적사장석。저위연구구내존재암장혼합작용제공료최직접적증거。
Plagioclases with special zonal structure were seen occasionally in diorite intrusion in Pingshun,southern Taihang Mountains.The plagioclases is characterized by high Ca-riched basic plagioclases (An>63)in the core and Na-riched in the rim,and a corrosion zone formed between the core and the rim that composed epidote and sericite.In addition there are distinctive compositional differences between core and rim of the plagioclase xenocrysts.Based on the evidences from the components and textures of the plagioclause,the following scenario about the magma evolution is tentatively suggested. Mantle magma originating from the EMI underplated to lower crust and crystallized Ca-riched basic plagioclases under high temperature.Crustal source magma originated by melting of lower crust with the help of heat-carrying mantle magma.Mantle magma and crustal magma ascended quickly along Taihang deep fault,intruded into shallow crust,and mixed.Meanwhile,early-formed basic plagioclases dissoluted because of sudden reduced pressure and formed corrosion zone with irregular shape.The crust-mantle magma crystallized Na-riched plagioclases on the basis of Ca-riched basic plagioclases and formed plagioclases with special zonal structure, providing the most direct evidence to magma mixing in the study area.