Abstract The Sveconorwegian orogeny encompasses magmatic, metamorphic and deformational events between ca. 1140 and 920 Ma at the southwestern margin of Fennoscandia. In recent years, the tectonic setting of this nearly 200 Myr-long evolution has been debated, with some workers arguing for collision with an unknown continent off the present-day southwest coast of Norway, and others advocating accretionary processes inboard of an active margin. Recently, it has been suggested that orogeny may have been gravity-driven by delamination and foundering of heavy subcontinental lithospheric mantle in an intraplate setting, in some ways similar to proposed sagduction processes in the Archaean. Resolving the tectonic setting of the Sveconorwegian orogen has implications for correlation with other orogens and Rodinia supercontinent reconstructions and for assessments of the evolution of plate tectonics on Earth, from the Archaean to the present. Here, we present new mapping and geochronological data from the Bamble and Telemark lithotectonic units in the central and western Sveconorwegian orogen – the former representing a critical region separating western parts of the orogen that underwent long-lived high- to ultrahigh-temperature metamorphism and magmatism from parts closer to the orogenic foreland that underwent episodic high-pressure events. The data show that the units constituting the Sveconorwegian orogen most likely formed at the southwestern margin of Fennoscandia between ca. 1800 and 1480 Ma, followed by fragmentation during widespread extension between ca. 1340 and 1100 Ma marked by bimodal magmatism and sedimentation. A summary of Sveconorwegian magmatic, metamorphic and depositional events in the different units shows disparate histories prior to their assembly with adjacent units. The most likely interpretation of this record seems to be that episodic, Sveconorwegian metamorphic and deformational events in the central and eastern parts of the orogen represent accretion and assembly of these units. This process most likely took place behind an active margin to the southwest that sustained mafic underplating in the proximal back-arc, resulting in high- to ultrahigh-temperature metamorphism in the western parts. In this interpretation, all features of the Sveconorwegian orogen are readily explained by modern-style plate tectonic processes and hypotheses involving some form of vertical, intraplate tectonics are not supported.

中文翻译：

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Sveconorwegian 造山运动——Fennoscandia 支离破碎的西南边缘的再融合

摘要 Sveconorwegian 造山运动包括大约 10 年之间的岩浆、变质和变形事件。Fennoscandia 西南边缘的 1140 和 920 Ma。近年来，这一长达近 200 Myr 的演化的构造背景一直存在争议，一些工人主张与现今挪威西南海岸外的未知大陆发生碰撞，而另一些人则主张活动边缘内部的增生过程。最近，有人提出造山运动可能是由板块内环境中重的次大陆岩石圈地幔的分层和沉没引起的重力驱动，在某些方面类似于太古代中提出的凹陷过程。解决 Sveconorwegian 造山带的构造环境对于与其他造山带和罗迪尼亚超大陆重建的相关性以及评估地球上板块构造从太古代到现在的演化具有重要意义。在这里，我们展示了来自 Sveconorwegian 造山带中部和西部的 Bamble 和 Telemark 岩石构造单元的新绘图和地质年代学数据——前者代表了一个分隔造山带西部部分的关键区域，该区域经历了长期的高温到超高温变质作用和岩浆作用来自更接近于经历了偶发性高压事件的造山前陆的部分。数据显示，构成 Sveconorwegian 造山带的单元最有可能形成于约 1800 和 1480 毫安，其次是在大约之间的广泛扩展期间分裂。1340 和 1100 Ma 以双峰岩浆作用和沉积为标志。Sveconorwegian 岩浆、变质和沉积事件在不同单元中的总结显示了在它们与相邻单元组装之前不同的历史。对该记录最可能的解释似乎是造山带中部和东部的偶发性、斯韦科诺威变质和变形事件代表了这些单元的增生和组装。这个过程很可能发生在西南的活动边缘后面，该边缘在近端弧后持续基性底镀，导致西部地区发生高温至超高温变质作用。在这个解释中，