Current methodologies and emerging trends in dolomite research: Review and Perspectives

Key words: 
• Dolomite problem /
• Mineralogical analysis /
• Isotope geochemistry /
• In situ analysis /
• Magnesium isotopes /
• Clumped isotopes

Abstract: Abstract: [Significance] The enduring ‘dolomite problem’, which has puzzled geologists for generations, remains a cornerstone of geoscientific inquiry. Its formation mechanisms not only drive breakthroughs in sedimentary diagenetic theories but also play a crucial role in predicting carbonate hydrocarbon reservoirs. [Progress] Traditional petrological-geochemical approaches remain pivotal in dolomite researches: (1) Mineral characterization techniques, including X-ray diffraction, cathodoluminescence, and scanning electron microscopy, effectively reveal dolomite crystal structures, ordering degrees, and microtextural features; (2) Infrared and Raman spectroscopy facilitate high-precision differentiation dolomite from calcite and high-Mg calcite through molecular vibration pattern recognition, while also identifying microscopic bonding configurations of ions; (3) Major-trace elements and rare earth elements analyses provide crucial geochemical constraints for deciphering dolomitizing fluid properties, redox conditions, and Mg sources; (4) Carbon and oxygen isotopic analysis traces fluid mixing processes and reconstructs paleotemperatures, complemented by strontium isotopic systems that constrain the evolution pathways of paleoseawater. However, traditional approaches have been proved to be insufficient for precisely unraveling fluid evolution sequences during dolomitization due to the complexities caused by multistage diagenetic overprinting and uncertainties in reconstructing paleoseawater geochemical compositions. Recent technological advancements have provided novel insights, promoting the research to micro, quantitative, and dynamic process analysis. Magnesium isotopes enable quantitative modeling of Mg2+ transport pathways, while microscale in-situ techniques (e.g., LA-ICP-MS, EPMA) achieve submicron spatial resolution (<10 μm), overcoming the limitation of bulk-rock methods to characterizing multiphase diagenetic events. Concurrently, carbonate clumped isotope (Δ47) thermometry and U-Pb geochronology provide unique advantages in constraining temperature and absolute timing of dolomitization processes. [Conclusions and Prospects] Future research should place a high priority on the following areas: quantitative crystallographic analysis, multi-isotope systematics tracing techniques, in-situ and microanalytical elemental mapping, and machine learning-driven big data fusion. Establishing a multidisciplinary framework that combines mineralogical characterization, elemental geochemical tracing, and isotopic chronostratigraphy will be essential. By integrating multiscale analytical techniques, multi-source data fusion, and intelligent modeling approaches, it is possible to refine the paradigm of dolomite research and achieve significant theoretical advancements.