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The Langshan Group is an important constituent of the Precambrian metamorphic rocks in the Langshan area. The accurate determination of its metamorphic age is of great scientific significance for the further study of the Precambrian geological evolution in the region. Disputes remain regarding the metamorphism and deformation overprinting of the Langshan Group. This paper presents a detailed study comprising a field geological investigation, petrological observations, and zircon U-Pb aging of garnet-bearing mica quartz schists in the BangBang District. The result of detrital zircon U-Pb dating from the metamorphosed volcanic sedimentary rock series and geological investigation of the garnet-bearing mica quartz schists suggest the strata formed in the Neoproterozoic. The results from cathodoluminescence (CL) image analysis and U-Pb dating of zircons indicate a large number of metamorphic zircons exist in the garnet-bearing mica quartz schists. The metamorphic overgrowth rims of zircon from two samples were analyzed by LA-ICP-MS. The 206Pb/238U weighted average age of ca. 244 Ma of the zircon metamorphism rims represents the timing of Indosinian greenschist-amphibolite facies metamorphism in the Langshan area, which may be in response to the collision-type orogeny of the North China and Siberian plates in the Late Paleozoic. Acid-intermediate magmatic intrusive activities occurred in the Langshan area, and metamorphic events developed at the same time or at a later stage during the closure of the Paleo-Asian Ocean. [ABSTRACT FROM AUTHOR]

The Beiligaimiao magmatic Ni-Cu sulfide deposit is located in the northern rim of the North China Block, which was an active continental margin related to the southward subduction of the Paleo-Asian oceanic plate to the north in the Paleozoic. This deposit has never been studied before but is an excellent example of sulfide mineralization in arc settings that have been commonly overlooked by exploration geologists worldwide. Sulfide mineralization in the deposit is hosted in a mafic-ultramafic complex that consists of a small ultramafic body surrounded by an older and much larger gabbroic intrusion. Disseminated sulfide zones are present in both intrusive bodies but only those close to the surface within the ultramafic body have been mined in the past. The sulfide-mineralized ultramafic body is composed of olivine websterite and orthopyroxenite with a gradational contact between them. SIMS U-Pb dating of zircon crystals from a large olivine websterite sample yields a crystallization age of 269.4 ± 2.1 Ma, which is ∼25 Ma younger than the Erbutu subduction-related magmatic Ni-Cu sulfide deposit that occurs ∼50 km to the north. Orthopyroxene crystals in the Beiligaimiao ultramafic rocks have Mg # [100 Mg/(Mg + Fe), molar] of 77–78, significantly lower than those in the ultramafic rocks of the Erbutu deposit. Olivine crystals in the Beiligaimiao ultramafic rocks have forsterite (Fo) contents from 72 to 75 mol%, which are also significantly lower than those in the ultramafic rocks of the Erbutu deposit (Fo, 86–88 mol%). The mineral chemical data indicate a more fractionated parental magma for the former. Ca-depletion in olivine (i.e., <1000 ppm Ca), which is common for ultramafic cumulates in arc settings worldwide, is present in both deposits. Like Erbutu, the host rocks of the Beiligaimiao deposit are characterized by enrichments in light rare earth elements (REE) relative to heavy REE and pronounced negative Nb-Ta anomalies, consistent with ultramafic rocks in arc settings. The δ 34 S values of sulfide separates from the Beiligaimiao deposit are 1.7 to 2.5‰, significantly lower than those for the Erbutu deposit but still slightly higher than the MORB value (−1.5 to 0.5‰). Olivine websterites in the Beiligaimiao deposit have ε Nd from −8.9 to −9.5 and ( 87 Sr/ 86 Sr) i close to 0.7075, which are similar to those of an enriched lithospheric mantle. An orthopyroxenite sample from the deposit has much lower ε Nd (−12.6) coupled with much higher ( 87 Sr/ 86 Sr) i ratio (0.7132), indicating ∼25% crustal contamination. The Sr-Nd-S isotope data support the premise that both crustal contamination and addition of crustal sulfur played a role in triggering sulfur saturation in the parental magma of the Beiligaimiao deposit. Since the immediate country rocks are exclusively gabbros, these processes likely took place at depth. The close temporal and spatial association of the Beiligaimiao and Erbutu deposits points to the possibility that more Permian arc-type magmatic sulfide deposits are yet to be discovered in the region. [ABSTRACT FROM AUTHOR]

The article presents a study which discusses ore-controlling characteristics and ore-forming process of synchronous faults of polymetallic sulfide deposits in Dongshengmiao deposits in Inner Mongolia. Topics discussed include role of syn-sedimentary faults on sedimentary mineralization and volcanic activities, geological tectonic evolution and mineralization process in Langshan orogenic belt, and changes in lithology of the ore-bearing strata.

The article discusses research on geological tectonic evolution and mineralization of Langshan Orogenic Belt located in the Western Part of the Northern Margin of Craton in North China. Topics discussed include analysis of geological and mineral resources characteristics and genesis of ore deposits; process of geological tectonic evolution and development of Langshan orogenic belt; and relationship between ore deposits with ore-forming geological setting and tectonic evolution.

The article presents a study on uranium?lead (U-Pb) dating and laser ablation?inductively coupled plasma?mass spectrometry (LA-ICP-MS) of Middle Permian granite of Langshan Mountain, China and its indicating significance. Topics discussed include characteristics of granite such as finegrained texture and massive structure; chemical composition of granite and selection of zircon to carry on LA-ICP-MS U-Pb dating.

The article focuses on geochronology and petrology of the Beiligaimiao Magmatic Sulfide Deposit in the northern margin of North China Craton in inner Mongolia, and Beiligaimiao magmatic sulfide deposit is hosted in a small ultramafic intrusion which occurs in the southern part of the Central Asian Orogenic Belt (CAOB) in inner Mongolia. It also mentions that the Beiligaimiao ultramafic intrusion is mainly composed of lherzolite.

The Badaguan porphyry Cu Mo deposit is located in the Derbugan metallogenic belt of northeastern Inner Mongolia, China. The host granodioritic porphyry and the wall rock granitic porphyry were emplaced at 230 Ma and 238 Ma, respectively. The granodioritic porphyry has ( 87 Sr/ 86 Sr) i values of 0.70535–0.70549, ε Nd (t) values of 0.41–1.17, ε Hf (t) values of 1.30–6.51, and two–stage model ages (T DM2 ) of 1131–848 Ma. In contrast, the granitic porphyry is characterized by ε Hf (t) values from − 0.75 to 7.28 that yield T DM2 model ages of 1355–816 Ma. The geochemical and Sr Nd Hf isotopic data for the magmatic rocks associated with the Badaguan porphyry Cu Mo deposit indicate that these intrusions were generated by the partial melting of juvenile lower crust. The δ 18 O values of ore fluids from different mineralizing stages are between − 6.0‰ and + 1.5‰, and the fluid δD water values vary from − 119.3‰ to − 140.0‰, indicating a mixed fluid of magmatic and meteoric water, the S Pb isotopes show that the metal was mostly derived from a deep-seated magma that involved some crustal materials, with a narrow δ 34 S range (− 2.4‰ to + 3.5‰). We infer that the Badaguan porphyry Cu Mo deposit formed during a period of southeast–directed subduction of the Mongol–Okhotsk oceanic plate beneath the Erguna Block. [ABSTRACT FROM AUTHOR]

The petrogenesis and geodynamic setting of magmatic rocks in Eastern Tianshan, Xinjiang, are attracting increasing attention. This study explores these issues by providing SHRIMP zircon U–Pb dating, and element geochemical and Hf isotope data of magmatic rocks exposed in the Yandong region of Eastern Tianshan, Xinjiang. SHRIMP zircon U–Pb dating data indicate that the magmatic activities occurred around 335 Ma, and that mineralization of the Yandong porphyry Cu deposit occurred during the same period as that of the rock formation in the region or slightly later. All the magmatic rocks in Yandong are sub-alkaline or high-K, calc-alkaline with A/CNK values ranging from 0.91 to 2.70, enriched in K, Rb, and Ba and clearly depleted in Nb, Ta, P, Ti, and Th, and have geochemical characteristics typical of adakites (i.e, high Al2O3, high La/Yb ratios and Sr contents, low Y and HREE contents, and positive Eu anomalies).In situHf isotopic analyses of zircons that had previously been dated by SHRIMP yielded positive initial εHf(t) values ranging from +9.4 to +15.8. We suggest that the Palaeo-Tianshan oceanic crust subducted northward beneath the Dananhu-Tousuquan arc belt during the early Carboniferous, and the Yandong magmatic rocks were induced by partial melting of the subducted Palaeo-Tianshan oceanic slab, subsequently having been hybridized by peridotite in the mantle wedge. The slab melts play a crucial role particularly in the relatively closed magma system responsible for generating the Yandong porphyry Cu deposit. [ABSTRACT FROM AUTHOR]