The late Paleozoic tectonic setting of the Zongwulong Belt (ZWLB), a significant unit located in the northern Qaidam margin, Qinghai province, remains uncertain. Diabase dykes in the western part of the Zongwulong Belt offer insights into this issue. Field investigations reveal that the dips of the dykes are almost vertical, and they have sharp boundaries with the host rocks. These dykes consist of plagioclase, clinopyroxene, and opaque minerals exhibiting a characteristic porphyritic texture and massive structure. Zircon U-Pb dating of the dykes yields a weighted ²⁰⁶Pb/²³⁸U age of 289 ± 1 Ma. The dykes exhibit relatively high concentrations of TFeO, K₂O + Na₂O, and TiO₂, while the SiO₂ and MgO concentrations are relatively low. They display relative light-over-heavy REE enrichment, and lack negative Nb-Ta and Eu anomalies. The dykes underwent negligible crustal contamination, and experienced extensive fractional crystallization of olivine, clinopyroxene, and Fe-Ti oxides. Originating from the spinel–garnet transition zone at depths of approximately 75 km, the dykes result from garnet facies low-degree melting (5%–10%) in a continental rift setting. Combining these findings with regional geological data, we propose that the ZWLB likely experienced a continental rift in the west and exhibited a narrow oceanic environment in the east in the late Paleozoic period, potentially representing the most distant north branch of the East Paleo-Tethys Ocean.

Gold is strongly enriched (up to 12 ppb) in the Hongqigou tectonic zone, which represents a potential metal source for the Wulonggou goldfield. In this study, a suite of 20 elements (Au, Ag, As, B, Ba, Bi, Cd, Co, Cu, Hg, Mn, Mo, Ni, Pb, Sb, Sn, Ti, V, W, and Zn) were analyzed on 30 altered rock samples from the tectonic zone. Compared with the average abundance of the earth's crust, these samples are generally enriched in Hg, have comparable Au, Ba, and As, and depleted in Ba, Co, and W. We suggested that Au, As, Hg, and Ba are the major ore-forming elements. The coupling relationship in multielement variation patterns between the altered rocks (in the tectonic zone) and wall rocks indicates wallrock involvement during the alteration process. Correlation statistical analysis (with SPSS software) on the 20 elements suggests that the elements of Ag, Cu, Pb, Hg, and Cd are closely related, and useful pathfinder elements include As, Sb, Hg, W, Sn, Cu, Ni, Mn, and Zn.

The large Harizha copper (Cu) polymetallic deposit is located in the eastern section of East Kunlun Orogen. The ore-related lithologies include mainly the granodiorite, monzogranite, and their porphyries. Zircon U-Pb dating of the ore-bearing granodiorite porphyry and granite porphyry yielded Late Triassic age of 217 Ma. The rocks are characterized by being rich in SiO₂ (68.44–78.13 wt%) and high alkali (4.03–8.33 wt%) and peraluminous (A/CNK = 1.02–1.68). In general, the granite samples are peraluminous and high-K calc-alkaline. The rocks are significantly enriched in light rare earth elements (LREE), large ion lithophile elements (e.g., K, Rb, Ba) and other incompatible elements (e.g., U, Th), but are depleted in heavy rare earth elements (HREEs), with weakly negative Eu and Ce anomalies, resembling I-S transitional granite. The zircons have ε_Hf (t) = -8 to -4, and the corresponding zircon two-stage Hf model age (T_DM2) from 1.5 to 1.8 Ga. We speculated that the ore-forming materials in the mining area were mainly from partial remelting of crustal materials, and that the tectonic regime was post-collisional extension.