Palaeozoic – Early Mesozoic geological history of the Antarctic Peninsula and correlations with Patagonia: Kinematic reconstructions of the proto-Pacific margin of Gondwana

Plate Rotation of the Northern Antarctic Peninsula Since the Late Cretaceous: Implications for the Tectonic Evolution of the Scotia Sea Region

“…West Antarctica is divided into four geological terranes: Thurston Island, Marie Byrd Land, Haag Nunataks with Ellsworth-Whitmore Mountains and the Antarctic Peninsula (Dalziel et al, 1987(Dalziel et al, , 2021Grunow et al, 1987). The Antarctic Peninsula has developed as a long-lived convergent margin along the Gondwana margin since at least the Cambrian (Bastías et al, 2020;Riley et al, 2020Riley et al, , 2023. According to Millar et al (2002), the continental crust in western Palmer Land is as old as the Silurian (435-422 Ma), but it is as old as the Ordovician (487-485 Ma) in eastern Graham Land , which has been confirmed recently by Bastías et al (2020) based on inherited zircon cores geochronology from basement rocks.…”

Evolution of an Accretionary Complex (LeMay Group) and Terrane Translation in the Antarctic Peninsula

“…The Scotia Metamorphic Complex is exposed from the South Shetland Islands (Trouw et al., 1997), along the South Scotia Ridge (Bruce Bank; Riley, Carter, et al., 2022; Riley, Burton‐Johnson, et al., 2022) to the South Orkney Islands (Flowerdew et al., 2011), including Permian—Triassic metasedimentary rocks from Signy Island and Coronation Island (Figure 2). The units of the Scotia Metamorphic Complex and correlative Greywacke Shale Formation (South Orkney Islands) all have prominent Permian zircon U‐Pb age peaks at c. 265 Ma and Cambrian peaks at c. 530 Ma (Carter et al., 2017; Riley, Carter, et al., 2022; Riley, Burton‐Johnson, et al., 2022). White mica that forms the pervasive foliation within the Scotia Metamorphic Complex has been dated at c. 190 Ma by Flowerdew et al.…”

“…The dredged samples from Bruce Bank (Figure 2a), a submerged crustal block of the South Scotia Ridge, are of direct significance to the LeMay Group accretionary complex. Bruce Bank forms part of the widespread Scotia Metamorphic Complex and metasedimentary rocks along its southern margin have a very similar detrital zircon age profile to Group 1 of the LeMay Group with peaks at c. 262 Ma and c. 520 Ma (Figure 9; Riley, Carter, et al., 2022; Riley, Burton‐Johnson, et al., 2022). However a sample from the eastern margin of Bruce Bank (DR.225.28) has a very distinct profile with detrital zircon age peaks at c. 128 Ma and c. 185 Ma (Figure 9), strikingly similar to the Group 3 lithologies of Charcot Island and with a similar spatial relationship.…”

“…The Scotia Metamorphic Complex is a highly deformed metasedimentary wedge, which contains a significant proportion of ocean floor material (Dalziel, 2013; Trouw et al., 1997), and has a geological and accretional history from the Late Paleozoic to the Cenozoic. The Scotia Metamorphic Complex is exposed from the South Shetland Islands (Trouw et al., 1997), along the South Scotia Ridge (Bruce Bank; Riley, Carter, et al., 2022; Riley, Burton‐Johnson, et al., 2022) to the South Orkney Islands (Flowerdew et al., 2011), including Permian—Triassic metasedimentary rocks from Signy Island and Coronation Island (Figure 2). The units of the Scotia Metamorphic Complex and correlative Greywacke Shale Formation (South Orkney Islands) all have prominent Permian zircon U‐Pb age peaks at c. 265 Ma and Cambrian peaks at c. 530 Ma (Carter et al., 2017; Riley, Carter, et al., 2022; Riley, Burton‐Johnson, et al., 2022).…”

“…(2022) and Riley, Burton‐Johnson, et al. (2022) interpreted that Bruce Bank, along with the South Orkney microcontinent, formed part of the Antarctic Plate prior to translation to form the South Scotia Ridge. In the mid‐Cretaceous, Bruce Bank would have been located adjacent to the Gondwana margin in continuity with the other accretionary complexes (Figures 12b and 12c).…”