The Precambrian of Gotland, a key for understanding the Proterozoic evolution in southern Fennoscandia

Abstract

Abstract Gotland is an island in the central part of the Baltic Sea, with up to 800\xa0m Palaeozoic sedimentary rocks on top of a Precambrian basement belonging to the East European Craton. In this contribution, two major ductile deformation zones (Lickershamn - Ostergarn and Lilla Karlso-Ronehamn) are recognized and connected with the Vingaker-Nykoping and Linkoping-Loftahammar Deformation Zones in the adjacent Fennoscandian Shield. These deformation zones constitute the borders between three main Precambrian segments that are correlated with crustal units within the Fennoscandian Shield and concealed parts of the East European Craton east of the Baltic Sea. The Faro-Northern Gotland segment is dominated by continental Jotnian sandstones and Svecofennian metasedimentary rocks, separated from each other by a fault and an associated dolerite dyke. The metasediments show a specific provenance pattern with 3.29\xa0Ga, 2.95–2.63\xa0Ga and 2.11–1.96\xa0Ga sources, devoid of\xa0 1.48\xa0Ga small stitching plutons on southern Gotland penetrate the TIB 0 and 1a granitoids and are correlated with the Gotemar and Karlshamn plutons in the Fennoscandian Shield and several plutons in western and southern Lithuania.