ABSTRACT

Cadomian (Ediacaran–Cambrian) magmatic rocks have been reported in the eastern (e.g. the Çatalca and İhsaniye plutons) and western (e.g. the Binkılıç and Safaalan plutons) parts of the Istranca (Strandja) Massif. This paper aims to investigate the tectonic setting and the magma evolution history of the Cadomian magmatic rocks using both new and previously existing geochemical and geochronological data. The meta-granitoid rocks with intermediate to felsic composition are the main magmatic activity in the region. They intrude into metamorphic basement rocks composed of gneiss, schist, amphibolite, calc-schist, and quartzites (the Tekedere group). These plutons show strong foliation and traces of the polyphase metamorphism. All plutons are peraluminous and slightly metaluminous, mostly calc-alkaline and high-K calc-alkaline, and plot into the volcanic arc granites (VAG) field on the tectono-magmatic discrimination diagrams. The zircon U–Pb crystallization ages of the plutons are between 525.3 ± 3.5 Ma and 548.7 ± 2.3 Ma. Initial εNd values vary from −0.02 to 1.86. Nd-T_DM model ages range between 1.08 and 1.24 Ga and indicate that the primitive magmas were originated and/or assimilated by the remelting of Neoproterozoic juvenile crustal rocks. New geochemical and geochronological data suggest a magma generation within a subduction-related magmatic arc setting in response to the southward subduction of the Proto-Tethys Ocean during the Late Precambrian-Early Palaeozoic period in the Istranca Massif.

摘要

据报道，卡多姆（埃迪卡拉纪-寒武纪）岩浆岩在伊斯特兰卡（Strandja）地块的东部（例如Çatalca 和İhsaniye 岩体）和西部（例如Binkılıç 和Safaalan 岩体）部分。本文旨在利用新的和以前存在的地球化学和地质年代学数据研究卡多姆岩浆岩的构造背景和岩浆演化历史。中长英质成分的变花岗岩是该地区主要的岩浆活动。它们侵入由片麻岩、片岩、角闪岩、钙片岩和石英岩（Tekedere 组）组成的变质基岩。这些岩体显示出强烈的叶理和多相变质作用的痕迹。所有的岩体都是过铝质和微金属化的，主要是钙碱性和高钾钙碱性，并绘制到构造-岩浆鉴别图上的火山弧花岗岩（VAG）场。岩体的锆石 U-Pb 结晶年龄介于 525.3 ± 3.5 Ma 和 548.7 ± 2.3 Ma 之间。初始 εNd 值从 -0.02 到 1.86 不等。钕-T_DM模型年龄介于 1.08 和 1.24 Ga 之间，表明原始岩浆起源于和/或同化新元古代幼年地壳岩石的重熔。新的地球化学和地质年代学数据表明，在伊斯特兰卡地块晚前寒武纪-早古生代期间，原特提斯洋向南俯冲，在与俯冲相关的岩浆弧环境中产生了岩浆。