Dolomite Paleogenesis in the Huron Domain of South Ontario

本项目旨在进一步探讨休伦地区泥盆系、志留系、奥陶系碳酸盐岩和寒武系砂岩中层控、近水平向白云化层的性质和成因。限制流体流动的时间和这些流体的化学性质，以及这些白云岩床在近地表环境中形成的程度，而不是在不同的埋藏深度由热液和埋藏过程形成的，是这项研究的基本组成部分。这些目标将通过综合岩心、岩石学和地球化学工具来实现。安大略省石油和天然气储存库（OGSR）的岩心设施库将用于提供休伦域内的钻孔岩心样本，以及布鲁斯核电站设施的岩心。**白云化发生在石灰石（CaCO3）逐渐转变为白云石（Ca(MgCO3)2）时。白云化可通过多种地质和地球化学过程发生，包括：a) sabkha型，b)混合含水层，c)渗流回流，d)埋藏压实，e)热液。这些过程会导致地层密度的变化，从而改变基岩的物理性质，包括孔隙度和渗透率的增加。从这个意义上说，白云化作用可以通过在岩化作用后创造渗透性通道以及适合油气聚集的局部地质构造的可能性来影响地下水系统的演化。******

The purpose of this project is to further investigate the nature and origin of stratabound, near- horizontally oriented dolomitized beds within Devonian, Silurian, Ordovician carbonates and Cambrian sandstones of the Huron Domain. Constraining timing of fluid flow and chemistry of these fluids and the extent to which these dolomite beds formed in near surface environments as opposed to formation at variable burial depths by hydrothermal and burial processes are fundemental componenet of this investigation. These objectives will be achieved using integrated core, petrographic and geochemical tools. The core facility Library of the Ontario Oil and Gas Repository (OGSR) will be used to provide drilled core samples from within the Huron Domain in addition to cores from Bruce Nuclear Station facility for the purpose of this investigation.**Dolomitization occurs when limestone (CaCO3) is progressively changed to dolomite (Ca(MgCO3)2). Dolomitization can occur by a broad range of geologic and geochemical process including: a) sabkha type, b) mixed-water aquifer, c) seepage reflux, d) burial compaction, and e) hydrothermal. These processes lead to a change in formation density that can alter physical properties of the bedrock, including, increased porosity and permeability. In this sense, dolomitization can influence groundwater system evolution through the creation of permeable pathways following lithification and the possibility of localized geologic structure suitable for the accumulation of hydrocarbons.******