Eastern Segment of the Kiselevka–Manoma Terrane (Northern Sikhote Alin): Paleomagnetism and Geodynamic Implications

摘要

The comprehensive geological–geophysical study of the lower Cretaceous volcanosedimentary rocks of the Kiselevka block of the Kiselevka–Manoma lithotectonic terrane made it possible to reach the following conclusions: (1) The composition of the volcanogenic rocks and the lithology of the sediments of the Kiselevka block indicate their formation in a within-plate oceanic setting; the petro- and geochemical characteristics of the studied volcanic rocks are similar to those of the Hawaiian hot spot. (2) The distinguished characteristic component of the natural remanent magnetization of the volcanosedimentary rock complex of the Kiselevka block yields a positive fold test and age similar to that of the rocks. According to the orientation of this characteristic component, the paleolatitudes of the rock formation (18° ± 5° N) and the coordinates of the paleomagnetic pole (Plat = 18.6°, Plong = 222.4°, dp = 5.2, dm = 9.1°) of the Kiselevka Block were determined. (3) The kinematic reconstructions based on the obtained and published data indicate that, (1) in the Valanginian–Albian, the Kiselevka Block migrated northwestward with the Izanaga Plate at a velocity of 15–20 cm/yr, passing over 5 thou. km up to the Eurasian margin (the Korean Peninsula); (2) in the Albian–Campanian, the block, as a fragment of the Kiselevka–Manoma accretionary wedge, moved along the Eurasian transform margin with a velocity of 4–5 cm/yr to its present-day position, where it was integrated into the continental plate.