Precambrian marine dolomite cements:review and perspectives
M arine dolomite cement is widely developed in the Precambrian era,whereas its occur-rence in the Phanerozoic is scarce.Precambrian marine dolomite cement has attracted extensive attention in recent years due to its diversity,complex origins,and potential implications for Precambrian seawater chemistry.Research on Precambrian marine dolomite cement mainly focuses on two aspects:one is the for-mation mechanism through mineralogical analysis,and the other is the investigation into the unique Pre-cambrian'aragonite-dolomite sea'conditions as reflected by marine dolomite cement.The origin of marine dolomite cement incorporates both primary precipitation and mimetic dolomitization.However,due to a lack of reliable geochemical evidence,there is ongoing controversy in this field.In addition,both the pre-cipitation mechanism of the primary dolomite and the corresponding seawater chemical conditions remain unclear.The identification of precursor minerals for mimetic dolomite is controversial.Based on previous studies,it can be summarized the spatial and temporal distribution,petrological and mineralogical charac-teristics,and geochemical characteristics.Subsequently,the current research status on the formation mechanism of marine dolomite cements from three aspects,including primary precipitation,secondary re-placement,and growth assemblage morphology.Finally,it can be proposed that three aspects should be enhanced:(1)The genesis of diverse types of marine dolomite cements should be investigated based on the principles of mineral nucleation and growth theory,combining with micro area or in-situ geochemical analysis;(2)he specific contribution of microorganisms to the formation of marine dolomite cements re-quires assessment;(3)To gain a comprehensive understanding of the evolution of Precambrian seawater properties,exploration of the origin of marine dolomite cement is imperative.
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维普
