Dissolution enables dolomite crystal growth near ambient conditions

• 成果类型: Article
• 署名作者: Kim, Joonsoo; Kimura, Yuki; Puchala, Brian; Yamazaki, Tomoya; Becker, Udo; Sun, Wenhao
• 署名单位: University of Michigan System; University of Michigan; Hokkaido University; University of Michigan System; University of Michigan
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-13098
• DOI: 10.1126/science.adi3690
• 发表日期: 2023-11-24
• 页码: 915-920
• 关键词: total-energy calculations; specchio-di-venere; microbial mediation; pantelleria island; calcium-carbonate; hypersaline lake; late pleistocene; lagoa-vermelha; mixing zone; dolomitization

摘要

Crystals grow in supersaturated solutions. A mysterious counterexample is dolomite CaMg(CO3)(2), a geologically abundant sedimentary mineral that does not readily grow at ambient conditions, not even under highly supersaturated solutions. Using atomistic simulations, we show that dolomite initially precipitates a cation-disordered surface, where high surface strains inhibit further crystal growth. However, mild undersaturation will preferentially dissolve these disordered regions, enabling increased order upon reprecipitation. Our simulations predict that frequent cycling of a solution between supersaturation and undersaturation can accelerate dolomite growth by up to seven orders of magnitude. We validated our theory with in situ liquid cell transmission electron microscopy, directly observing bulk dolomite growth after pulses of dissolution. This mechanism explains why modern dolomite is primarily found in natural environments with pH or salinity fluctuations. More generally, it reveals that the growth and ripening of defect-free crystals can be facilitated by deliberate periods of mild dissolution.