论文部分内容阅读
早期成岩作用指的是沉积物在沉积至浅埋藏过程中在沉积颗粒、孔隙水及沉积环境水介质之间发生的一系列物理、化学及生物学作用.早期成岩作用可以在沉积物中形成地球化学层序带,自上而下可依次出现氧化带(OX带)、硫化物还原带(SR带)和甲烷带(ME带)等. 对这些带的部分作用机理的认识已日趋深入,并进而出现了较为成功的早期成岩作用方面的模型.这些模型多以底层水的有机质、溶解氧和硫酸根的浓度,沉积物的孔隙率、沉积速率,以及溶质的扩散系数及有机质的反应速率(后两者可为孔隙水温度的函数)等为已知参数,计算出有机质、溶解氧和硫酸根的浓度在沉积物中随深度的分布,从而区分出氧化带和硫化物还原带.但是,现有的模型只能用来计算一次性的沉积事件,即只能用来计算一个沉积层;而对于有多次性的沉积事件发生,从而形成多个沉积层,并且这些沉积层之间相互存在影响的情形,现有的模型无法应用.而多层沉积的情况在实际中又是经常发生的.因此,本文在现有的单层早期成岩作用模型的基础上,发展出了一个多层的早期成岩作用模型,尝试解决这一问题.
Early diagenesis refers to a series of physical, chemical and biological interactions that occur between sediments, pore water, and sedimentary aqueous media during sedimentation to shallow burial. Early diagenesis can form the Earth in sediments (OX zone), sulfide reduction zone (SR zone) and methane zone (ME zone) from top to bottom, etc. Understanding of the mechanism of some of these zones has been deepening Furthermore, more successful models of early diagenesis appear.These models are mostly based on the concentrations of organic matter, dissolved oxygen and sulfate in the bottom water, the porosity and sedimentation rate of sediments, the solute diffusion coefficient and the reaction rate of organic matter ( The latter two can be pore water temperature function) as the known parameters, calculate the concentration of organic matter, dissolved oxygen and sulfate in the sediment distribution with depth, so as to distinguish between the oxidation zone and sulfide reduction zone However, Existing models can only be used to calculate a one-time sedimentary event, ie only one sedimentary layer, and multiple occurrences of sedimentary events to form multiple sedimentary layers, and this The existing models can not be applied, and the situation of multi-layer deposition often occurs in reality.Therefore, based on the existing single-layer model of early diagenesis, A multi-layered model of early diagenesis was tried to solve the problem.