New Cretaceous Paleomagnetic and Geochronologic Data From the Antarctic Peninsula: Constraints on the Pre‐Opening Tectonic Evolution of the Drake Passage

Abstract Reconstructing oroclinal orogens along the Fuegian Andes‐northern Antarctic Peninsula provides critical constraints on the pre‐opening tectonic evolution of the Drake Passage, although such efforts are limited by a lack of reliable Cretaceous paleomagnetic and geochronological data. Here, we present new paleomagnetic, 40 Ar/ 39 Ar, and apatite U‐Pb geochronological data to reconstruct the oroclinal bending of this belt. Our results reveal that oroclinal bending in the northern Antarctic Peninsula (∼67°–63°S) and the Fuegian Andes both occurred at ∼100–90 Ma, mainly driven by compression from the northward‐moving Antarctic Peninsula and southeastward‐moving Cordillera Darwin Metamorphic Complex. We propose that the orocline Drake Passage boundary primarily formed during this period. This oroclinal weak zone served as a fundamental prerequisite in opening the Drake Passage, facilitating the separation of the Fuegian Andes and Antarctic Peninsula.