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Typical ophiolitic rock assemblages such as siliciclastic rocks, basalts and gabbros, together with the subduction-related intermediate-acidic intrusive rocks, are newly discovered in the Tongjiang-Fuyuan area of the Heilongjiang Provence, NE China. To determine the formation age and genesis of the mafic rocks (basalts and gabbros) and intermediate-acidic intrusive rocks (granodiorites) in the area, as well as their geodynamic settings, the whole-rock geochemical analysis and zircon LA-ICP-MS U-Pb dating were carried out. Zircon U-Pb results suggest that the granodiorites are 93–95 Ma and gabbro is 95 Ma, respectively. Geochemical results show that the gabbros and basalts exhibit characteristics of ocean island basalt (OIB) affinity and are typically related to having originated from mantle plumes. While the granodiorites show the nature of the island-arc magmatic rocks and may originate from the lower crust. Based on the coeval igneous rock associations and regional tectonic evolution, we conclude that the late Cretaceous magmatic rocks in the Tongjiang-Fuyuan area are the product of continuous subduction of the Palaeo-Pacific plate and reflect the subduction rollback process of the Palaeo-Pacific plate. [ABSTRACT FROM AUTHOR]

The glaucophanic rocks, including the garnet‐barroisite schist (09YL10) and glaucophane aegirine‐augite schist (09YL12) from the Heilongjiang Complex exposed in the Yilan area, have been petrographically investigated, in order to contribute to the discussion on the high‐P/T metamorphism that took place in the suture zone between the Jiamusi and Songliao blocks, NE China. The mineral assemblages of peak metamorphic stage are characterized by garnet (100XCa < 26) + epidote + barroisite/katophorite + phengite (Si < 6.84 pfu) + chlorite + quartz + rutile + haematite and barroisite/katophorite + glaucophane + aegirine‐augite (Jd < 30) + epidote + phengite (Si < 6.84 pfu) + haematite ± quartz ± chlorite for the investigated samples 09YL10 and 09YL12, respectively. By applying P–T pseudosection modelling in the NCKFMASHTO system, the peak metamorphic conditions yield 550–580°C/1.1–1.3 GPa and 500–550°C/1.1–1.3 GPa, for sample 09YL10 and 09YL12, respectively, indicating the epidote‐amphibolite facies metamorphism. Furthermore, the equilibrium mineral assemblages and the estimated P–T conditions define the Alpine‐type clockwise P–T paths for the Heilongjiang glaucophanic rocks, suggesting isothermal decompression (ITD) and/or slight heating during the beginning of the exhumation process. These P–T paths significantly match to the warm subduction trajectory, indicating the tectonic regimes similar to those of young oceanic slabs subduction zones and subsequent continental orogenic belts. Taking available regional geochronological data into account, we propose that the final subduction/collision between the Jiamusi and Songliao blocks took place in the Jurassic, effected by the Palaeo‐Pacific subduction system, leading to formation of the Heilongjiang glaucophanic rocks and their high‐P/T metamorphosed pelitic country rocks. [ABSTRACT FROM AUTHOR]