Metamorphism of the Seve Nappes at Åreskutan, Swedish Caledonides
Metamorphism of the Seve Nappes at Åreskutan, Swedish Caledonides
复制标题
瑞典喀里多尼德省 Åreskutan 七座推覆体的变质作用
作者：
Jan
摘要在阿雷斯库坦地区发生了两次严重推覆。下部推覆体由构造变质沉积物和角闪岩组成，变质于角闪岩相。上部推覆体（阿雷斯库坦推覆体）由高级混合片麻岩和变基性岩组成。两个推覆体被糜棱岩带分隔。广泛的糜棱岩化Sarv推覆体的残余被认为是发生在下塞夫推覆体和下外生岩的志留纪岩石之间。萨尔夫推覆体变质为绿片岩相。千枚岩带将Sarv推覆体与Lower Seve推覆体分开。角闪岩相下塞夫推覆体中的矿物组合表明重结晶温度约为550°C，压力为200-500 MPa。Mg和Fe在黑云母和石榴子石之间的分配系数约为KD = 0.18。加里东推覆平移期间，Sarv和Seve推覆体的糜棱岩基底部分发生了强烈的海退作用。在战神的片麻岩中.
Abstract Two Seve Nappes occur in the Areskutan area. The lower nappe is composed of a layered sequence of tectonized metasediments and amphibolites, metamorphosed in the amphibolite facies. The upper nappe (Areskutan Nappe) consists of high-grade migmatitic gneisses and metabasites. The two nappes are separated by a mylonite zone. A remnant of extensively mylonitized Sarv Nappe is believed to occur between the Lower Seve Nappe and the Silurian rocks of the Lower Allochthon. The Sarv Nappe is metamorphosed in greenschist facies. A phyllonitic zone separates the Sarv Nappe from the Lower Seve Nappe. The mineral assemblage in the amphibolite facies Lower Seve Nappe indicates recrystallization temperatures around 550°C and pressures of 200–500 MPa. The distribution coefficients for the partitioning of Mg and Fe between biotite and garnet are about K D = 0.18. Strong retrogression occurred in the mylonitic basal parts of the Sarv and Seve Nappes during Caledonian nappe translation. In the gneisses of the Ares...