The supercontinent cycle explains how landmasses amalgamate into super-plates, which dismember after a ~100 Myr tenure in a quasi-periodic manner controlling Earth’s long-term geodynamics. Pangea, the latest supercontinent, formed ~330 Ma, began to rift ~240 Ma finally broke-up ~200 Ma and it is generally considered the template for all previous supercontinents. The formation of Pangea as a super-plate 330 Ma show a major pitfall: The geologic record between 330-270 Ma predicts >1500km of shortening/extension and shows large volumes of magmatism and metamorphism of unidentified origin. Here I present a tectonic reconstruction that reconciles the inconsistent datasets. In this model, after the initial amalgamation of Pangea the comprising plates kept interacting at least between 320 Ma and 270 Ma, when finally established as a super-plate for a brief period of <70 Myr, which following most recent models would be too short to control the mantle dynamics.

The Mineoka Ophiolite Melange is located at the intersection of the Pacific, Philippine Sea, Eurasia and North American plates. The origin of the Mineoka ophiolite is disputed and it has been ascribed to a fully subducted plate or part of the Pacific and Philippine Sea plates. In this paper, we present a kinematic reconstruction of the Mineoka Ophiolite Melange and its relation with the Pacific Plate, based on new paleomagnetic data and Ar-Ar geochronology. In addition to standard analyses for paleolatitudes, we performed a Net Tectonic Rotation analysis on sheeted dykes to infer the paleospreading direction that formed the ophiolite. The analysis show that 85–80 Ma MORB pillow lavas erupted at a paleolatitude of N ~16˚, whereas ca. 50 Ma pillow lavas formed at N ~34˚. Net Tectonic Rotation analysis suggests that the spreading direction was NE 60˚. Ar-Ar ages yielded 53–49 Ma for MOR lavas and 41–35 Ma for island arc volcanism. The formation of this ophiolite occurred in the back-arc spreading of the Nemuro-Olyutorsky arcs of the NW Pacific. It infers that the final consumption of Izanagi below Japan instigated a subduction jump and flipped its polarity. Subduction initiated parallel to the ridge, and a piece of the original back-arc crust got trapped near the Japan trench during the northwards motion of the Philippine Sea Plate. The contrasting motion between the Pacific and Philippine Sea plates generated a highly unstable setting followed by a subduction zone that left a small-sized and short-lived plate, surrounded by subduction zones.