Diagenesis and Faults
Published:January 01, 1993
The influence of faulting processes on the distribution of diagenetic events during basin evolution is reviewed. Faults have potentially a dual role as high permeability pathways (which enhance fluid flow) and as seals (which constrain fluid flow and generate permeability barriers). The complexities of fault array development and the fluid pressure evolution of different lithologies during burial lead to fluid flow in basins being controlled by the creation and destruction of complex 3D migration pathways. Microstructural analysis can help to identify the evolution of such pathways and provide input for the quantitative modeling of fluid flow processes. Analysis of the diagenetic histories within and outside fault zones reveals differences which can be used to establish the links between deformation mechanisms, fault zone diagenesis, and the influence of these processes on fluid flow in sedimentary basins. The combination of microstructural analysis of deformation and diagenetic sequences together with the assessment of the propagation and geometrical evolution of faults reported here offer an important route for the evaluation of (a) fault zone porosity/permeability histories; (b) the evolution and distribution of fault seals; (c) the timing of fault activity during burial and basin development; and (d) identification of fluid migration pathways and the changing drainage patterns that control the distribution and timing of open/closed compartments within the basin. A model is presented emphasizing the influence of evolving fault plane geometries, displacement patterns, tip zone processes, and fault rock evolution in controlling the juxtapositions and windows for fluid communication and diagenetic changes.
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Diagenesis and Basin Development
This publication grew out of a conference of the same name held in 1991. Most, though not all, of the chapters included in the volume were presented at that conference. The purpose of the volume is to examine links between sediment diagenesis--and consequent porosity and permeability modification--and aspects of the development of sedimentary basins. The papers in the book provide some important guidelines and insights that may be useful to the exploration geologist in the development of new play concepts, and to the academician many stimulating ideas for further research.