南大别山毛屋榴辉岩相岩石组合的矿物学和岩石学特征  

MINERALOGICAL AND PETROLOGICAL CHARACTERISTICS OF THE ECLOGITE FACIES ROCK COMBINATION AT MAOWU AREA IN THE SOUTH DABIE OROGENIC BELT

作　　者：张勇[1] 江来利[1] 吴维平[1] 孙先如[2] 

机构地区：[1]安徽省地质调查院,安徽合肥230001 [2]安徽省地质实验研究所,安徽合肥230001

出　　处：《安徽地质》2004年第3期161-166,共6页Geology of Anhui

基　　金：国家自然科学基金项目40072070资助

摘　　要：不同于大别山其他榴辉岩,太湖县毛屋榴辉岩相岩石组合含顽火辉石,至目前尚未有人对此作过报道。该地榴辉岩相岩石组合包括二矿物榴辉岩,顽火榴辉岩,石榴斜方辉石岩,石榴辉石橄榄岩和顽火辉石糜棱岩等。它们可能是岩浆母岩在深部结晶再经历榴辉岩相变质作用改造而成。矿物组合中出现成分很纯的顽火辉石。榴辉岩中的单斜辉石低钠。除二矿物榴辉岩外,石榴石以富镁铝榴石为特征,镁铝榴石端员组分平均达71.8%。根据岩石化学成分,毛屋榴辉岩可划分为铁钛型和镁铬型两类。该榴辉岩相岩石组合的成岩压力介于18-26kb,温度介于931-1076℃之间,属高温榴辉岩。该榴辉岩相岩石组合沿深剪切带快速折返到地壳浅层次,几乎没有受到深部减压迭加变质的影响。Being different from other eclogites in the Dabie orogen,the eclogite facies rock combination occurring in Maowu area in the southern Dabie orogen contains enstatites,so far there is no report about this. The eclogite facies rock combination includes two-mineral eclogite,enstatite eclogite,garnet orthopyroxenite, garnet pyroxene peridotite and enstatite mylonite.They are probably formed by eclogite facies metamorphism of magmatic protoliths.There are pure enstatite occurring in the rock combination.The clinopyroxenes in the eclogites are relatively Na_2 O low.Except the two-mineral eclogite,the garnets are rich in pyrope,the pyrope end member reaches 71.8%.According to the chemical compositions of the eclogites,the eclogites can be divided into two types:a.Fe-Ti type;b.Mg-Cr type.The rock forming pressure is about 18-26kb,and the temperature is about 931-1076.So they belong to high-temperature eclogites.The eclogite facies rock combination was quickly exhumed to shallow crust level along deep shear zone,and showes no overprinting metamorphism induced by deep level pressure reduction.

关 键 词：榴辉岩相 岩石组合 矿物学 岩石学 毛屋:南大别山 

分 类 号：P571[天文地球—矿物学]