Geochronology and Geochemistry of Late Paleozoic Volcanic Rocks and Their Relationship With Iron and Molybdenum Deposits in Xilekuduk Area, Northern Margin of Junggar

A large number of intermediate basic volcanic rocks and porphyry Cu-Mo deposits as well as volcanic-hosted magnetite deposit have been recently discovered in the Xilekuduk area. However, no reports concerning petrogenesis and age or their relationship with mineralization have been published to date. The purpose of this study was to make up for the absence of previous studies on Devonian volcanic activities in the area and to confirm the relationship between two stages of volcanic activities and mineralization so as to provide important theoretical basis for mineral exploration. Based on research results of zircon U-Pb geochronology and element geochemistry of volcanic rocks in the area, the ages of dacite, andesite, and stomatal andesite are considered as 375.2 ± 2.9 Ma, 386.5 ± 3.0 Ma, and 317.9 ± 2.9 Ma, respectively, corresponding to the Middle Devonian and Late Carboniferous Period. The Devonian volcanic rocks belong to the high-K calc-alkaline series and island arc volcanic rocks, which are enriched in LREE, strongly enriched in large ion lithophile elements Th, Rb, Ba, and K and relatively depleted in high-field strength elements (HFSEs) Nb, Ta, and Ti. The Carboniferous volcanic rocks are enriched in LREE, as well as the large ion lithophile elements Th, Rb, Ba, and K are strongly enriched, while depleted in the HFSEs Nb, Ta, and Ti; moreover, the contents of TiO2 and V are 0.94–0.97% and 178–183×10–6, which are higher than those of island arc basalts. According to mineralogical typomorphic characteristics and geochemical analysis, magnetite mineralization is divided into two phases. The early stratiform magnetite ore MT1 has magmatic characteristics, forming a volcanic rock type magnetite deposit related to Devonian volcanic eruption and sedimentation (375–386 Ma). The magnetite MT2 in the magnetite-quartz vein is considered as hydrothermal genesis, which is a metal mineral in the early metallogenic stage of Carboniferous (317.1 ± 2.9 Ma) volcanic eruption and subvolcanism, and may be related to porphyry molybdenum mineralization. Therefore, the volcanism and Fe-Cu-Mo mineralization in this area is characterized by multistage superimposed mineralization.

Cenozoic volcanism along Dahongliutan fault in the West Kunlun Mountains, China: Implication from distribution of volcanic rocks, volcanic geology, and geochemistry

In the West Kunlun Mountains, four volcanic fields (i.e., Kangxiwa, Dahongliutan, Qitaidaban, and Quanshuigou) are distributed along the Dahongliutan fault, which is approximately 180 km long. Based on field investigations, chronological measurements, and geochemical analysis of some volcanic fields, the results of geological, geochemical, and geophysical research by the predecessors in the corresponding study areas are summarised. The volcanic activities in these areas were mainly effusive eruptions, explosive eruptions, and phreatomagmatic eruptions. In this study, we discovered the Qitaiyanhu volcanic field for the first time and determined that the 14C age of the lacustrine strata underlying the Qitaiyanhu lava flows are 13110 ± 40 a B.P., indicating that there may still have been volcanic activities in the late Pleistocene and even the Holocene in the Dahongliutan fault area. The base surge deposits, which are the products of the interaction between magma and water, were found in the Kangxiwa volcanic field. The four shoshonitic rock fields of Kangxiwa, Dahongliutan, Qitaidaban, and Quanshuigou are likely to be products of different evolution stages from the same magma source area. The magmatic origin of these volcanic fields may be related to the upwelling of the asthenosphere, triggered by the collision between the Indian and Tarim plates.Supplementary material at https://doi.org/10.6084/m9.figshare.c.5353446

Rancang Bangun Mesin Replika Penghasil Gas Vulkanik sebagai Studi Awal Monitoring Erupsi Gunung Berapi

Indonesia is one of the countries that has the third-largest number of volcanoes in the world. Several volcanoes are still active today. This places Indonesia prone to disasters from the volcano. One of the volcanic activities is characterized by the release of poisonous gases such as CO2. At a certain threshold, this poisonous gas can kill living things. This research has designed a gas-producing engine as a replica of volcanic gas. This machine is very supportive of the development of volcanic gas research on a laboratory scale because it has the advantage of being lighter, simpler construction, cheaper and portable machine construction process. The gas produced by the machine is tested using the Dragger X-am 7000. , CO2, H2S, SO2, and CO. The results were obtained for 60 seconds of starting the engine, namely CH4 2.0% LEL, CO2 1.6% Vol, H2S 4.3 ppm, SO2 1.0 ppm, and CO 271 ppm.