ABSTRACT Several orogenies have shaped the bedrock of southern Sweden. While mafic intrusions represent significant sources of information for reconstructing geodynamics and crustal evolution, the characterization of the various generations of such intrusions in Sweden remains limited. We report in situ zircon U–Pb ages and Hf isotope data from a Fe-Ti eclogite and a coronitic metagabbro from the Eastern Segment in southern Sweden. Crystallisation ages at 1683 ± 17 Ma of the eclogite suggest affiliation with the surrounding 1730–1660 Ma Transscandinavian Igneous Belt intrusions that dominate the Eastern Segment. Secondary zircon growth and Pb-loss in the eclogite sample at 1459 ± 44 Ma and the crystallisation of the metagabbro at 1431 ± 26 Ma overlap and are related to magmatic activity during the Hallandian orogeny. Zircon Hf isotope signatures with chondritic and sub-chondritic values at ~1683 Ma and ~1431 Ma, respectively, correspond to an enriched (or mildly depleted) source in line with a “Mixed Svecofennian Crustal Reservoir”. These isotope signatures are more enriched than those in the surrounding gneisses. Zircon isotope data from the herein analysed zircon grains indicate that the eclogite and metagabbro had an enriched mafic source in the mid to lower crust, or within the subcontinental lithospheric mantle below Fennoscandia.

中文翻译：

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瑞典南部榴辉岩和变辉长岩中的锆石 U-Pb-Hf 同位素数据揭示了一个共同的长寿演化和丰富的来源

摘要 几个造山运动塑造了瑞典南部的基岩。虽然镁铁质侵入体代表了重建地球动力学和地壳演化的重要信息来源，但瑞典各代此类侵入体的特征仍然有限。我们报告了来自瑞典南部东段的 Fe-Ti 榴辉岩和冠层变辉长岩的原位锆石 U-Pb 年龄和 Hf 同位素数据。榴辉岩的结晶年龄为 1683 ± 17 Ma，表明它与周围 1730-1660 Ma 的横贯斯堪的纳维亚火成岩带侵入体有关，这些侵入体在东段占主导地位。榴辉岩样品在 1459 ± 44 Ma 处的次生锆石生长和 Pb 损失与 1431 ± 26 Ma 处变辉长岩的结晶重叠，并且与哈兰德造山运动期间的岩浆活动有关。球粒陨石和亚球粒陨石值分别为~1683 Ma 和~1431 Ma 的锆石 Hf 同位素特征对应于符合“混合 Svecofennian 地壳储层”的富集（或轻度耗尽）源。这些同位素特征比周围片麻岩中的同位素特征更丰富。来自本文分析的锆石颗粒的锆石同位素数据表明榴辉岩和变辉长岩在中下地壳或 Fennoscandia 下方的次大陆岩石圈地幔内具有富集的镁铁质源。