关键词: 张广才岭地体, 二叠纪—侏罗纪, 黑龙江洋, 岩浆期次, 低角度俯冲

Abstract: The extensive development of Permian to Jurassic magmatic rocks in the Zhangguangcai Terrane, Northeast China, provides important information for understanding the regional tectonic evolution. This study systematically summarizes the geochronological and whole-rock geochemical characteristics of 266-163 Ma magmatic rocks from this terrane, identifying four distinct episodes of magmatic activity: The 266-240 Ma magmatic activity is mainly composed of adakitic and I-type magmatic rocks, while the 229-210,209-185 and 184-163 Ma magmatic activities are mainly composed of adakitic, I-type and A-type magmatic rocks. Based on analysis of magma sources and tectonic settings, combined with regional geological constraints, we propose that the tectono-magmatic history of the Zhangguangcai Terrane was primarily controlled by the evolution of the Heilongjiang Ocean. Specifically, westward subduction of the ocean beneath the terrane occurred during 266-210 Ma, followed by ocean closure during 210-180 Ma, which culminated in the final collision between the Jiamusi-Khanka block and the Songliao block. The obduction of residual oceanic crust during 180-163 Ma triggered tectonic exhumation and final emplacement of the Heilongjiang accretionary complex. The occurrence of a magmatic lull (240-230 Ma) is attributed to low-angle subduction of the Heilongjiang Ocean. Our findings indicate that the Zhangguangcai Terrane represents a combination of Late Paleozoic to Early Mesozoic accretionary complexes and continental arcs, rather than an ancient block with Neoproterozoic basement.

Key words: Zhangguangcai Terrane, Permian to Jurassic, Heilongjiang Ocean, magmatic phases, low-angle subduction