Paleomagnetic and Rock Magnetic Properties of Gabbrodiorites From the Lower Amur Complex of the Zhuravlevka-Amur Terrane (Sikhote-Alin Orogenic Belt)

Abstract

The paper presents the results of paleomagnetic and rock magnetic studies on phase-I gabbrodiorites of the Lower Amur Complex of the Zhuravlevka-Amur terrane (Poni massif, Poni-Mulinsky ore cluster), which were used to determine that at the time the Lower Amur intrusive Complex formation (Cenomanian-Turonian) the Priamurskaya zone was located between the Central Sikhote-Alin fault in the east and the Priamursky fault in the west, which is 10–13° north of its current position. It is shown that starting from the middle of the Cenomanian there were no latitudinal movements of the Priamurskaya zone of the Zhuravlevka-Amur terrane relative to the Eurasian continent. However, a more than 20-degree counterclockwise rotation of the zone relative to the continent was recorded, which is easily interpreted in terms of the ball-bearing model invoking an action of the Amur and Central Sikhote-Alin en echelon left-lateral strike-slip faults. Left-lateral strike-slip fault systems could easily be channels for mantle material supply during the formation of the largest porphyry copper deposit Malmyzh, which, along with the Poni-Mulinsky ore cluster, is part of the Lower Amur mineragenic zone.