Paleomagnetism of the Middle Jurassic Sedimentary Rocks of the Elgon Formation of the Ulban Terrane

Abstract

The paper presents new findings of paleomagnetic studies on Middle Jurassic sedimentary rocks of the Elgon Formation of the Ulban Terrane from coastal outcrops along the Ulban Bay (53.5°N, 137.7°E). Demagnetization yielded a pre-folding characteristic component of magnetization. No inclination shallowing effect for the characteristic magnetization vector was revealed in sandstone specimens of the Elgon Formation. The coordinates of the paleomagnetic pole and the paleolatitude at which the studied rocks deposited were calculated: Plat = -34.3 (34.3)°; Plong = 161.2 (341.2)°; dm = 2.7 dp = 5.3, paleolatitude = 0.1° (+2.7°/-2.6°) S. The acquired paleomagnetic data show evidence for the deposition of rocks of the Ulban Terrane in the Middle Jurassic at the boundary between the Asian paleocontinent and the Paleo-Pacific which later formed part of the Sikhote-Alin Orogenic Belt.