Paleomagnetic constrains on the assembly processes of the Antarctic Peninsula

The mid-Cretaceous paleo-Pacific ocean witnessed increased mantle plume activity, high oceanic crust production rate, enhanced subduction-related magmatism, and widespread short-lived intense deformation. The Antarctic Peninsula located at the Pacific margin of Gondwana and strongly influenced by the exceptionally pan-Pacific tectonic events during the mid-Cretaceous. Therefore, plate reconstruction of the Antarctic Peninsula and its implication to the global geodynamics, paleo-ocean circulation and paleoclimate have become one major subject for pan-Pacific geoscience studies. However, this is difficult because of the small number of reliable paleomagnetic data of the Antarctic Peninsula at the early stage of mid-Cretaceous. In this study, we obtained a key ca. 120-105 Ma paleopole from the Byers Peninsula, Livingstone Island, South Shetland Island, during the global ocean crust peak production period. Plate reconstruction reveals that the Western-Central Domain of the Antarctic Peninsula experienced clockwise rotation between ca. 155 Ma and 120-105 Ma, and large-scale anticlockwise rotation from ca. 120-105 Ma to 90 Ma. This anticlockwise rotation was ascribed to induce the final formation of the Antarctic Peninsula. This assembly age coincides with the global-scale plate reorganization at 105-100 Ma, which might associate with the eruption of mantle superplume in the southern Atlantic region.

Acknowledgments

This research was funded by the National Key R&D Program of China (2018YFC1406904), the Natural Science Foundation of China (NSFC) (41930218, 41706222, 41372082), the open foundation project (KLPTR-03) of Key laboratory of paleomagnetism and Tectonic Reconstruction, Ministry of Land and Resources.