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Sn-W multimetal mineralization in the Dong Van region, North-Eastern Vietnam was studied using statistical and multivariate approaches based on 890 samples of stream bottom sediments collected for assaying for 27 elements. The findings of frequency analysis demonstrated that Pb, As, Bi, Li, Sn, W, Ta, Ce, Ag, Sb, and Be have close ties with multimetal ores, implying that these elements can be used as prospecting indicators for multimetal mineralization. In addition, correlation matrix and dendrogram studies were also applied to subdivide the elements in the stream bottom sediment samples assays into two groups: associated with multimetal mineralization (Be-Sn-W-Bi, and, to a lesser extent, Li-Pb sub-groups) and not associated with the mineralization: (As-Cd-Sc-Cr-Ce-La, Co-Ni-V, and Ga-Ge-Ba sub-groups). Sn and W were found to be the best indicator elements for the mineralization, according to the findings of geochemical modeling and location of their anomalies in the region. Furthermore, extensive Sn and W anomalies were identified in the Dong Van region (using threshold values (mean ± 3 STD), providing the most important indications for multimetal mineralization prospecting in the region. The studies also suggest genetic ties between the region’s multimetal mineralization and the northwest-southeast fault system and concealed granitoid blocks. Finally, the performed statistical analyses (with the use of threshold values) of stream bottom sediments assays allowed revealing indicator elements and their geochemical anomalies and using them as an effective tool in further prospecting and exploration for multimetal mineralization in the region.

In northeastern Vietnam, hydrothermal‐metasomatic kaolinite-pyrophyllite from the secondary quartzite origin has been found in many places, including Pin Ho, Ban Ngai, Khe Khoai, Pec Sec Leng, Tan Mai ore occurrences, etc. They are exploited together with pyrophyllite, alunite, and high‐alumina quartzite as a byproduct. There were 810 chemical and mineral samples in the Quang Ninh area collected to investigate hydrothermal‐metasomatic kaolin resources. The ore minerals consist of kaolin-group minerals (kaolinite, dickite), pyrophyllite, quartz with minor sericite, alunite, diaspora, etc. They were identified by X-ray diffraction, and microscope and scanning electron microscope coupled with energy-dispersive X-ray spectroscopy analyses. Chemical analyses of major oxides were carried out on clays and parent rock samples by X-ray fluorescence spectrometry. The similarity-analogy in ore geology and mineral resource estimation based on statistical methods are employed to estimate hydrothermal‐metasomatic kaolin resources from the Quang Ninh area in northeastern Vietnam. The mineral resource estimation based on statistical methods shows 2.21 million tons of kaolin obtained by the content of aluminum oxide over 28% of the Pec Sec Leng mine, accounting for 14.3% in total. The similarity-analogy in ore geology indicates 158.16 million tons of kaolinite-pyrophyllite ores, of which, 22.0 million tons are kaolin. These methods display that the Quang Ninh area contains mainly pyrophyllite rather than kaolin resources. Our study suggests that the Quang Ninh area can be considered as a potential pyrophyllite resource in northeastern Vietnam for future exploration. Furthermore, the one resource estimation based on similarity-analogy in ore geology method shows an overview of the prospect on kaolinite-pyrophyllite resources in the Quang Ninh area, northeastern Vietnam.

The Song Hien Rift basin, located in northeast Vietnam, has been identified as an important region for gold deposits, including the Pac Lang deposit. Several methods like petrographic observations, elemental analyses, and geochemical elements and vertical zoning models of primary halo have been used to describe geological characteristic of this deposit. The investigation focused on examining the geological events that occurred both before and after the formation of the ore. The use of ICP-MS analysis and element concentration contrast enabled an effective assessment of the relative degrees of denudation that occurred at the Pac Lang deposit. The findings of this study were consistent with prior research on ore deposit geology, geochemical primary-halo, and examination of geochemical indicator zoning patterns for gold ore bodies. The study's application of singularity analysis for evaluating the degree of denudation provides important geological information that can aid in data interpretation. The results of the study can also have significant reference value in furthering our understanding of the post-ore deformation of deposits and in the investigation of unknown orebodies in northeast Vietnam. There indicate that, the research's findings suggest that the use of singularity analysis to evaluate the degree of denudation is a valuable tool for exploring potential gold deposits and enhancing our knowledge of gold deposit geology in northeast Vietnam. Overall, this study contributes to the existing body of knowledge on gold deposits in the Song Hien Rift basin and can serve as a useful reference for future research in the area. [ABSTRACT FROM AUTHOR]

The Indosinian orogeny, which was regarded as the collision event between the South China and Indochina blocks that occurred in Southeast Asia, including Vietnam, resulting in the formation of the Indosinian mountain range. However, the question of how many times collision between these blocks occurred in the past and during which period remains unanswered. Furthermore, the closure of the ancient ocean and the evidence of its remnants between the South China and Indochina Blocks are still the subjects of serious debate. The underlying origin of the Indosinian thermo-tectonism is uncertain. The entire region was affected by the thermal-tectonic processes in the west, caused by the collision of the Sibumasu plate and Indochina block. The absence of evidence supporting the Indosinian as a significant mountain-building event is highlighted through an examination of regional paleogeography, as well as palaeontological and thermochronological data. There is no conclusive evidence to suggest that the Indochina and South China blocks collided during the Triassic times. A plate tectonic scenario that describes the Indosinian orogeny as a reactivation event triggered by the accretion of the Sibumasu block to Indochina is favored. [ABSTRACT FROM AUTHOR]