North Korea is host to world-class metallic mineral deposits, such as the Komdok Cu–Pb–Zn polymetallic mineral belt, but little is known about the resource. To better understand the genesis of the Cu mineralization around the China–North Korea border, we determined the U–Pb, Re-Os, and Rb–Sr ages of three deposits in the area. Sulfide samples from the Hyesan Cu deposit produced Rb–Sr isochron ages of 127.4 ± 4.5 Ma. The Wanbaoyuan Cu deposit yielded a molybdenite Re–Os isochron age of 127.5 ± 3.2 Ma, and a granodiorite sample from the Linjiang Cu deposit gave a zircon U–Pb age of 129.5 ± 0.8 Ma. Combined with geochronological data from previous studies, these new ages suggest that the Cu mineralization occurred mainly during the Cretaceous, and the rollback of the Paleo-Pacific Plate was responsible for the Cu mineralization in NE China–North Korea border.

Characteristic samples from the No. 1 ore body of the Jinlong bauxite deposit in Guangxi Province, China, were assessed to determine their chemical composition using whole-rock geochemical analysis, their mineral components using X-ray diffraction, their thermal characteristics via differential thermal analysis, thermogravimetry and differential thermogravimetry, and their dissemination characteristics by scanning electron microscopy/energy-dispersive spectrometry. The results show that the average Al₂O₃ content in the Jinlong bauxite deposit is 41 % and that the Al₂O₃/SiO₂ ratio is approximately 2.17, and thus, the ore may be defined as low-grade bauxite. The main minerals found in the ore were diaspore (20.3–43 %), gibbsite, clays and hematite. In differential thermal analysis results, the bauxite samples exhibit two distinct endothermic peaks, with the dehydration of gibbsite occurring in the 200–260 °C range and the dehydration of diaspore occurring in the 524–550 °C range. Thermogravimetry and differential thermogravimetry indicate four decomposition stages: evaporation of adsorbed water (50–160 °C), gibbsite decomposition (190–280 °C), goethite decomposition (190–280 °C) and diaspore dehydroxylation (460–580 °C). The diaspore belongs to the orthorhombic dipyramidal class and exists primarily in three dissemination forms—euhedral and subhedral grain, bean and oolitic shaped, and aphanitic and microcrystalline aggregates, and is always accompanied by kaolinite and pyrophyllite.