CAJ | 학술논문

西宁陨石具有典型的球粒结构，球粒轮廓依稀可辨-模糊，基质重结晶程度中-高等，次生斜长石粒度5-40μm，部分颗粒大于50μm。橄榄石和低钙辉石的化学成分均一：球粒中橄榄石Fa24．7-25．2，平均Fa24．9，相对标准偏差PMD值0．64％；低钙辉石Fs21．3-21．9 En77．6-78．2 Wo0．46-0．57，平均Fs21．5，Fs的PMD值0．84％。说明该陨石已达热力学平衡状态，为平衡型普通球粒陨石。根据该陨石结构构造特征、金属含量、矿物化学组成特征和热变质特征（平衡温度为778℃），西宁陨石被划分为L群普通球粒陨石，岩石类型为5型，但已开始向6型过渡。该陨石的冲击变质程度为S3，风化程度W0。陨石母体形成之后遭受了冲击变质作用和热变质作用，导致原始球粒破碎、脱玻化和基质重结晶。
서저운석구유전형적구립결구，구립륜곽의희가변-모호，기질중결정정도중-고등，차생사장석립도5-40μm，부분과립대우50μm。감람석화저개휘석적화학성분균일：구립중감람석Fa24．7-25．2，평균Fa24．9，상대표준편차PMD치0．64％；저개휘석Fs21．3-21．9 En77．6-78．2 Wo0．46-0．57，평균Fs21．5，Fs적PMD치0．84％。설명해운석이체열역학평형상태，위평형형보통구립운석。근거해운석결구구조특정、금속함량、광물화학조성특정화열변질특정（평형온도위778℃），서저운석피화분위L군보통구립운석，암석류형위5형，단이개시향6형과도。해운석적충격변질정도위S3，풍화정도W0。운석모체형성지후조수료충격변질작용화열변질작용，도치원시구립파쇄、탈파화화기질중결정。
The Xining meteorite has a typically chondritic texture .The matrix displays a moderate to high degree of re-crystallization .Most plagioclase grains have a diameter of around 5-40μm with a few grains greater than 50μm. The chemical compositions of olivine and low-Ca pyroxene in the Xining meteorite are homogeneous:e.g., olivine (Fa24.7-25.2, avg.Fa24.9, PMD 0.64%);low-Ca pyroxene (Fs21.3-21.9, avg.Fs21.5, PMD 0.84%;En77.6-78.2, avg. En78.6;Wo0.46-0.57, avg.Wo0.46).This feature indicates that the olivine and low-Ca pyroxene in the Xining meteor-ite are in thermodynamic equilibrium and the Xining meteorite should be classified as an equilibrated ordinary chon -drite.Based on the textural characteristics , metal abundance , chemical composition of silicate minerals and thermal metamorphic characteristics (the equilibrium temperature is 778℃), the Xining meteorite is classed as an L5 ordi-nary chondrite that is beginning to change to an L 6.The degrees of shock metamorphism and terrestrial weathering are S3 and W0, respectively.The parent body of the Xining meteorite suffered impact and thermal metamorphism , which resulted in fragmentation of chondrules , devitrification of glass , and recrystallization of the matrix .