早期海相碳酸盐胶结物特征、成因及古环境意义OA

Early marine carbonate cements are an important component of marine carbonate depositional systems.They record key information on paleo-seawater chemistry and early diagenetic processes and play a significant role in the formation and evolution of carbonate reservoirs.Considering the limited research conducted in China and the great resource potential of marine carbonate reservoirs,this study systematically reviews and synthesizes previous studies on early marine carbonate cements worldwide.Their spatial and temporal distribution,morphological characteristics,mineral compositions,and major controlling factors are summarized.Previous studies indicate that early marine carbonate cements are widely developed in both ancient and modern carbonate depositional systems.Their primary mineral compositions are mainly aragonite and high-Mg calcite,and their common morphologies include acicular,fibrous,columnar,granular and others.The mineralogical and morphological evolution of these cements is mainly controlled by multiple factors,including seawater Mg/Ca ratio,CO₃²⁻,phosphate ions,SO₄²⁻,organic matter,temperature,salinity,sediment substrate,and crystal habits.Early marine cementation can significantly modify the pore structure of primary sediments and enhance the stability of the rock framework,thereby exerting an important influence on pore preservation and subsequent diagenetic evolution of carbonate reservoirs.A comprehensive understanding of the formation characteristics and controlling factors of early marine carbonate cements is crucial for revealing carbonate sedimentation–diagenesis processes and reservoir formation mechanisms,and it provides important theoretical guidance for hydrocarbon exploration in carbonate reservoirs.