Geodynamic setting of Mesozoic magmatism in NE China and surrounding regions: Perspectives from spatio-temporal distribution patterns of ore deposits

Abstract

North-eastern China and surrounding regions host some of the best examples of Phanerozoic juvenile crust on the globe. However, the Mesozoic tectonic setting and geodynamic processes in this region remain debated. Here we attempt a systematic analysis of the spatio-temporal distribution patterns of ore deposits in NE China and surrounding regions to constrain the geodynamic milieu. From an evaluation of the available geochronological data, we identify five distinct stages of ore formation: 240-205. Ma, 190-165. Ma, 155-145. Ma, 140-120. Ma, and 115-100. Ma. The Triassic (240-205. Ma) magmatism and associated mineralisation occurred during in a post-collisional tectonic setting involving the closure of the Paleo-Asian Ocean. The Early-Mid Jurassic (190-165. Ma) events are related to the subduction of the Paleo-Pacific Ocean in the eastern Asian continental margin, whereas in the Erguna block, these are associated with the subduction of the Mongol-Okhotsk Ocean. From 155 to 120. Ma, large-scale continental extension occurred in NE China and surrounding regions. However, the Late Jurassic magmatism and mineralisation events in these areas evolved in a post-orogenic extensional environment of the Mongol-Okhotsk Ocean subduction system. The early stage of the Early Cretaceous events occurred under the combined effects of the closure of the Mongol-Okhotsk Ocean and the subduction of the Paleo-Pacific Ocean. The widespread extension ceased during the late phase of Early Cretaceous (115-100. Ma), following the rapid tectonic changes resulting from the Paleo-Pacific Oceanic plate reconfiguration. © 2013 Elsevier Ltd.