Abstract

The mineral assemblage Pl + Bt + Qtz + Grt + Sil + Ilm + Rt ± St (without cordierite) found in metapelites at the Kitelä garnet deposit in the North Ladoga Metamorphic Complex, southeastern Fennoscandian Shield, was produced by Barrovian-type (elevated-pressure) medium- to high-temperature metamorphism. The P–T parameters of the metamorphic processes were evaluated using the technique of multiequilibrium thermobarometry (TWEEQU) at 610–700°C and 6–8 kbar. The metamorphism was associated with deformations and anatexis (partial melting) in a water-saturated system. The U–Pb monazite age (ID‑TIMS) of the Kitelä schists is 1800 Ma (the final stage of the Svecofennian orogeny). Evidence for the identified metamorphic event is found locally in high-strain zones among schists with low- to medium-pressure mineral assemblages that are common to the North Ladoga Metamorphic Complex and the Svecofennian Orogen as whole (Buchan-type metamorphism). The Kitelä schists were retrogressed at temperatures lower than 300°C. This retrogression occurred not during the final stage of the Late Svecofennian metamorphic event but was related to a younger low-temperature fluid-assisted overprinting.

中文翻译：

---

东南芬诺斯坎迪亚盾构北拉多加带状变质复合体中晚期斯威科芬尼亚高压变质的证据。

摘要

Fennoscandian Shield东南部的北拉多加变质综合体Kitelä石榴石矿床的变质岩中发现的矿物组合Pl + Bt + Qtz + Grt + Sil + Ilm + Rt±St（不含堇青石）是由Barrovian型（高架压力）中到高温变质。该P -牛逼使用多平衡热压法（TWEEQU）在610–700°C和6–8 kbar的条件下评估了变质过程的参数。变质与水饱和系统中的变形和厌食（部分熔化）有关。Kitelä片岩的U–Pb独居石年龄（ID‑TIMS）为1800 Ma（Svecofennian造山运动的最后阶段）。鉴定出的变质事件的证据是在具有低至中压矿物组合的片岩中的高应变区中局部发现的，这些岩体是整个北拉多加变质复合体和整个Svecofennian造山带（Buchan型变质）所共有的。Kitelä片岩在低于300°C的温度下倒退。