硅质碎屑-碳酸盐混合沉积:进展与分类新启示
- 收稿日期:
2024-11-14
- 网络出版日期:
2025-03-04
摘要: 【意义】碎屑-碳酸盐组分的混合沉积研究能指示古气候、古环境、物源供给、海/湖平面升降,更与矿产、油气资源息息相关而越来越受到重视。【进展】混合沉积主要可分为成分混合(狭义)与结构混合(广义),混积岩作为混合沉积产物,以往的分类方案主要有四分法、三分法、两分法。但受限于黏土组分是否应参与混积岩的划分一直存在争议,文章提供一个分类新思路,借此可对类似混合沉积研究多提供一项选择。【结论】在以碎屑组分与碳酸盐组分两端元划分的基础上,通过颗粒的定量统计,以此可判断沉积期的水动力条件。与传统分类方案相比,既保留了碳酸盐组分、碎屑颗粒、灰泥、黏土四个端元,又同时兼顾了视觉呈现效果与便捷操作可行性。此外,重新厘定混合沉积作用,具体划分为:间断(事件)混合、相混合、原地(生物)混合与沉淀混合四种类型。并将溯源混合、成岩混合、岩溶混合、裂缝混合等不能反映原始沉积环境的四种作用归为假混合作用。【展望】碳酸盐岩与碎屑岩作为沉积学的两大分支,一直被作为独立的学科体系进行研究。对混合沉积的研究还有望帮助理解碳酸盐-碎屑组分之间的矿物来源、相互作用方式与沉积过程,完善碎屑岩与碳酸盐岩学科体系。
Mixed siliciclastic - carbonate: Progress and new idea of classification
- Received Date:
2024-11-14
- Available Online:
2025-03-04
Abstract: [Significance] The study of detrital-carbonate mixed components can indicate paleoclimate, paleoenvironment, provenance supply, and sea/lake level change, and is closely related to mineral and oil & gas resources, so it is paid more and more attention. [Progress] Mixed sediments can be mainly divided into compositional mixing (narrow sense) and structural mixing (broad sense), and mixed sediments as mixed sedimentary products, the previous classification mainly includes four, three, and two components. However, it has been controversial whether clay components should participate in the classification of mixed deposits. This paper provides a new idea of classification, which can provide another choice for the study of similar mixed sediments [Conclusions] Based on the division of clastic and carbonate components, the hydrodynamic conditions of the sedimentary period can be judged by quantitative statistics of fine sediment content. Compared with the traditional classification scheme, the four components of carbonate grains, detrital grains, (dolo)micrite, and clay are retained, while the visual presentation effect and convenient operation feasibility are taken into account. In addition, mixed sedimentation was redefined into four types: punctuated mixing, facies mixing, in situ mixing, and precipitation mixing. Four kinds of processes that cannot reflect the original sedimentary environment, such as source mixing, diagenetic mixing, karst mixing, and fracture mixing, are classified as false mixing. [Prospects] As two branches of sedimentology, carbonate rock and clastic rock have been studied as independent subject systems. The study of mixed sediments is also expected to help understand carbonate-clastic components' mineral sources, interaction modes, and deposition processes and improve the discipline system of clastic and carbonate rocks.