Abstract
AbstractThe Khorat Plateau on the Indochina Terrane is known to have formed during the closure of the Tethys Ocean, although the origin of its potash mineral deposits is a topic of current debate. Data from a borehole on Savannakhet Basin is used in this study to re‐define the evaporation processes of the study area. Geochemical analyses of halite from various borehole‐derived evaporite strata have elucidated the fluid sources from which these ores formed. Measured δ11B indicated that ore deposits formed primarily due to evaporation of seawater, although non‐marine fluids affected the later stages of the evaporation process. Fluctuations in B and Br concentrations in carnallite‐ and sylvite‐rich strata indicate the influence of fresh water. Boron concentration in carnallite unit indicated the influence of hydrothermal fluids. From the relative timings of these various fluid influxes, the evolution of these evaporates can be divided into four stages: (1) an initial marine evaporation at the beginning of the deposit's formation, where seawater (and minor fresh water) trapped on the uplifted Khorat Plateau produced sediments and salts with Br contents lower than those of normal marine‐derived evaporites; (2) a transgression stage, where seawater recharged the basin; (3) a hydrothermal infiltration stage, which was coeval with the late Yanshan movement; and (4) a stage of fresh water supply, as recorded by fluctuations in B and Br contents, inferring intermittent fresh water influx into the basin. Thus, although evaporites on the Savannakhet Basin primarily formed via marine evaporation, they were also influenced to a significant degree by the addition of non–marine fresh water and hydrothermal fluids.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
