Mesozoic magmatism and crustal evolution in the Xing’an–Mongolia Orogenic Belt, NE China

Age, tectonic setting, and metallogenic implication of Phanerozoic granitic magmatism at the eastern margin of the Xing’an–Mongolian Orogenic Belt, NE China

The south‐east margin of the Xing'an–Mongolian Orogenic Belt (SM‐XMOB) is a tectonic junction that is characterized by widespread Late Palaeozoic to Early Mesozoic igneous rocks. To determine the tectonic settings and provide new constraints on the regional tectonic evolution, petrological, geochronological, geochemical, and Hf isotope analyses have been conducted on the Permian volcanic rocks along the SM‐XMOB. Zircon U–Pb geochronological data indicate that these rocks were formed at 271.4 ± 3.2 Ma and 268.3 ± 3.2 Ma during the Early–Middle Permian. Geochemical results suggest that the volcanic rock samples have 61.5–66.4 wt% SiO2 and 0.98–1.71 wt% MgO, and belong to the calc‐alkaline series, suggesting an affinity with fractionated I‐type granite. They also exhibit positive zircon εHf (t) values ranging from + 8.6 to + 14.7, indicating that the primary magmas were dominantly derived from partial melting of Early Palaeozoic juvenile lower crustal. These volcanic rocks show an enrichment in large‐ion lithophile elements (LILEs; e.g., Rb, Th, and U) and depletion in high‐field‐strength elements (HFSEs; e.g., Nb, Ta, Ti, and P), similar to that from an active continental margin setting. We therefore propose that the widespread Permian volcanic rocks in the SM‐XMOB were closely associated with the southward subduction of the Palaeo‐Asian Ocean (PAO) Plate to the lithosphere beneath the XMOB, and that the PAO had not closed prior to the Middle Permian in the SM‐XMOB.

Early–Middle Permian plutons in the Langshan area, western Inner Mongolia, China, and their tectonic implications

ABSTRACTThe Ordovician plutons in the Erguna Block, NE China, can be classified into two groups: Early Ordovician diorites with zircon U–Pb ages ranging from 486 to 485 Ma and Middle Ordovician gabbros and granites with zircon U–Pb ages ranging from 466 to 463 Ma. The diorites are calc-alkaline in nature and are characterized by weak to moderate enrichments of large ion lithophile elements (LILE) and light rare earth elements (LREE) relative to high field strength elements (HFSE) and heavy rare earth elements (HREE). The gabbros and granites have high total alkali contents, and all samples are enriched in LREE and LILE and depleted in HFSE such as Nb, Ta, and Ti. Isotopically, Early Ordovician diorites display values that are less radiogenic [εHf(t) = + 9.9–+16.8] compared to those of Middle Ordovician gabbros [εHf(t) = − 3.0–+5.0]. Middle Ordovician granites have positive εHf(t) values of +1.4 to +4.3 and two-stage Hf model ages (TDM2) of 1167 to 1356 Ma. These data indicate that the diorites may have been generated by the partial melting of a recently metasomatized mantle source, whereas the gabbros and granites may have been formed by the partial melting of enriched lithospheric mantle and Mesoproterozoic crust, respectively. Our results, combined with other regional results, suggest that Early Ordovician magmatism was likely associated with the northward subduction of the Heihe–Xilinhot oceanic plate beneath the Erguna–Xing’an Block, whereas the Middle Ordovician gabbros and granites were most likely formed in an extensional setting controlled by the rollback of this subducted oceanic plate.

Review for "Geodynamic setting of the south‐east margin of Xing'an–Mongolian Orogenic Belt: Constraints from geochronology and geochemistry of the Permian volcanic rocks in Yanbian area, NE China"

Decision letter for "Geodynamic setting of the south‐east margin of Xing'an–Mongolian Orogenic Belt: Constraints from geochronology and geochemistry of the Permian volcanic rocks in Yanbian area, NE China"

Review for "Geodynamic setting of the south‐east margin of Xing'an–Mongolian Orogenic Belt: Constraints from geochronology and geochemistry of the Permian volcanic rocks in Yanbian area, NE China"

Review for "Geodynamic setting of the south‐east margin of Xing'an–Mongolian Orogenic Belt: Constraints from geochronology and geochemistry of the Permian volcanic rocks in Yanbian area, NE China"

Author response for "Geodynamic setting of the south‐east margin of Xing'an–Mongolian Orogenic Belt: Constraints from geochronology and geochemistry of the Permian volcanic rocks in Yanbian area, NE China"

Decision letter for "Geodynamic setting of the south‐east margin of Xing'an–Mongolian Orogenic Belt: Constraints from geochronology and geochemistry of the Permian volcanic rocks in Yanbian area, NE China"

The age, geological setting, and types of gold deposits in the Yanbian and adjacent areas, NE China

Decision letter for "Geodynamic setting of the south‐east margin of Xing'an–Mongolian Orogenic Belt: Constraints from geochronology and geochemistry of the Permian volcanic rocks in Yanbian area, NE China"

Early Jurassic porphyry copper mineralization in NE China: A case study of the Yanghuidongzi deposit

Seismic evidence of on-going sublithosphere upper mantle convection for intra-plate volcanism in Northeast China

Metallogenic events and tectonic setting of the Duobaoshan ore field in Heilongjiang Province, NE China