Field data from recent geological mapping over a major part of the north-central Scandinavian Caledonides combined with published information give a detailed view of early Cambrian basin successions, comprising the Gärdsjön formation (Gf; Jämtland supergroup) in the Lower Allochthon and autochthonous equivalents (Dividal Group). The Gf comprises ten units of sandstone and siltstone or mudstone (Gf I—X, > 300 m thick). Green siltstones with red layers (Gf VI, c. 521 to 519 Ma) and green–grey siltstones at the top (Gf X, c. 516.5 to 513.5 Ma) are regional key horizons. Gf V, VI, VII, IX, and X deposition may be related to eustatic events. Restoration of Caledonian shortening reveals a major “Hornavan-Vattudal basin” (HVB; > 330 km NW–SE, > 400 km NE-SW) between the Grong–Olden culmination in the S and the Akkajaure–Tysfjord culmination in the N. Published zircon ages imply the latter separated the HVB from those shed from the Timan orogen in the N. The eastern basin margin straddles the present Caledonian erosional margin. Basement highs identified here within the Nasafjället, Bångonåive, and Børgefjellet “basement” windows define the western margin. They separate the HVB from the outer shelf towards the Iapetus Ocean in the W. The onset of sedimentation is time-related with E–W extension at c. 544–534 Ma. NNE–SSW-directed extension occurs after c. 518 Ma, perhaps related with Timan late-orogenic extension. The HVB is distinctly younger (c. 535–513.5 Ma) than Rodinia break-up and Iapetus ocean formation (> 550 Ma), comparable with post-rift basins in inner parts of modern passive margins.

Graphical Abstract

中文翻译：

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波罗的海-土卫八被动边缘内的早寒武世裂谷后盆地（斯堪的纳维亚喀里多尼亚中北部）

最近对斯堪的纳维亚喀里多尼亚半岛中北部主要部分进行地质测绘的现场数据与已发表的信息相结合，提供了早期寒武纪盆地序列的详细视图，其中包括下异地地区的 Gärdsjön 地层（Gf；Jämtland 超群）和本土等同物（Dividal）团体）。Gf 由十个单元的砂岩和粉砂岩或泥岩组成（Gf I—X，> 300 m 厚）。带有红色层的绿色粉砂岩（Gf VI，约 521 至 519 Ma）和顶部的绿灰色粉砂岩（Gf X，约 516.5 至 513.5 Ma）是区域关键层位。Gf V、VI、VII、IX 和 X 沉积可能与海平面上升事件有关。加里东缩短的恢复揭示了一个主要的“Hornavan-Vattudal盆地”（HVB；> 330公里西北-东南，> 400公里东北-西南），位于南部的格隆-奥尔登顶峰和北部的阿卡贾乌尔-蒂斯峡湾顶峰之间。锆石年龄意味着后者将 HVB 与北部蒂曼造山带脱落的岩石分开。东部盆地边缘横跨现在的加里东侵蚀边缘。这里在 Nasafjället、Bångonåive 和 Børgefjellet“地下室”窗口内确定的地下室高点定义了西部边缘。它们将 HVB 与西面的巨神海的外陆架分开。沉积的开始与 c 处的东西向延伸有关。544–534 马。NNE-SSW 定向延伸发生在 c 之后。518 Ma，可能与蒂曼晚造山运动有关。HVB 明显比罗迪尼亚分裂和土卫八海洋形成（> 550 Ma）年轻（约 535-513.5 Ma），与现代被动边缘内部的裂谷后盆地相当。

图形概要