Search

A set of 41 stream water samples of the Lo River catchment, Ha Giang province, collected in dry season was analyzed for pH, major cation and anion, trace element concentrations. The stream waters exhibits a midly acidic to alkaline, meanwhile, the Total Dissolved Solids (TDS) values have a wide range of 17.4–284.9 mg L–1. Among major cations and anions, the stream water within the Lo River catchment is characterized by the predominant presence of Ca2+ and . This compositional pattern gives rise to the emergence of the Ca–Mg–HCO3 water type as the most dominant species, followed by Na–Cl, Ca–Mg–Cl–SO4 and Na–HCO3–Cl types. However, the distribution of these water types corresponds closely with the geological conditions, with Na–Cl type prevailing in the watershed of granite complex, while watersheds characterized by lithologies such as Quaternary sediments, limestone, marble, shale, schist, and sandstone primarily exhibit the Ca–Mg–HCO3 water type. The dominant reaction in the water system is the dissolution of carbonate minerals, like calcite and dolomite, followed by the contribution of modest rainfall during the dry season, and small-scale processes of mixing and cation exchange. Comparison of major ions and trace element with technical standard reveal the stream waters are generally deemed suitable for the routine activities of the local population in Ha Giang province. However, stream water of a few specific sites may require treatment before these waters can be safely utilized. [ABSTRACT FROM AUTHOR]

The paper presents brief results of comprehensive studies of the water area of the Tatar Strait and Sea of Japan obtained on cruise 61 of the R/V "Akademik Oparin" in November–December 2020. The bottom relief and geophysical and gas-geochemical fields were refined, and new features of the geochemistry and mineralogy of bottom sediments were revealed. [ABSTRACT FROM AUTHOR]

Abstract—The paper gives brief results of comprehensive studies in the South China Sea obtained from a joint Russian–Vietnamese expedition in November 2019 (cruise 88 of the R/V "Akademik M.A. Lavrentyev"). The set of methods included acoustics, geophysics, geology, mineralogy,geochemistry, paleogeography, geomicrobiology, hydrooptics and hydrology. The seafloor relief, geophysical and gasgeochemical fields have been refined; new features of the geochemistry and mineralogy of the continental shelf of Vietnam and the adjacent deep-sea basins have been revealed. [ABSTRACT FROM AUTHOR]