Magnesium Isotope Constraints on the Holocene Hydromagnesite Formation in Alkaline Lake Dujiali, Central Qinghai‐Tibetan Plateau

Abstract

New Mg isotope data on Holocene hydromagnesite, modern lake and river waters from the Dujiali Lake, central Qinghai-Tibetan Plateau.• A thermodynamic-based box model simulates the behavior of the carbonate system Mg/Ca ratios and Mg isotopes during the evolution of the lake chemistry.• Low-Mg carbonate precipitation may be a common precursor process for driving hydromagnesite precipitation in evaporative lacustrine environments.

Magnesium Isotopes of Carbonate Reveal Seasonal Climate Variation in the Central East Asia During the Middle Eocene

“…The mean T (Δ 47 ) of 33°C for the carbonates (Figure 2b) is ∼10°C higher than today's global surface temperature (Burke et al., 2018; Caballero & Huber, 2013), supporting an intense evaporative environment in the region during the middle Eocene. Under the evaporative environments, calcium carbonates (calcite and/or aragonite) could have precipitated in the marginal areas of the lake, elevating the Mg/Ca ratios of the evolved brine remained in the lake and promoting magnesite precipitation (De Deckker, 2019; Lin et al., 2023).…”

“…Teng, 2017). For example, carbonate precipitation fractionates Mg/Ca and Mg isotopes and promotes hydromagnesite formation in alkaline Dujiali Lake, central Qinghai-Tibetan Plateau (Lin et al, 2023). Y.…”

“…Magnesium (Mg) isotope geochemistry provides a useful tool for studying low‐temperature processes (Li et al., 2015; F. Teng, 2017). For example, carbonate precipitation fractionates Mg/Ca and Mg isotopes and promotes hydromagnesite formation in alkaline Dujiali Lake, central Qinghai‐Tibetan Plateau (Lin et al., 2023). Y. Wang et al.…”