Coupling between pressure solution creep and diffusive mass transport in porous rocks
Coupling between pressure solution creep and diffusive mass transport in porous rocks
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DOI：
10.1029/2001jb000287
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发表时间：
2002-11
影响因子：
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通讯作者：
E. Gundersen;François Renard;D. Dysthe;K. Bjørlykke;B. Jamtveit
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文献类型：
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作者：
E. Gundersen;François Renard;D. Dysthe;K. Bjørlykke;B. Jamtveit
收到2000年9月29日；2002年1月25日修订；2002年1月30日接受；2002年XX月出版。压力溶解被广泛认为是上地壳韧性变形的一种机制。它由应力差驱动，其速率受温度、晶粒尺寸和流体化学的影响。压力溶解包括高应力下晶粒接触处的溶解和低应力下孔隙表面晶粒接触处的沉淀，通过孔隙空间中的沉淀或晶粒压痕导致孔隙率降低。对于一个在晶粒尺度上封闭的系统，压力溶解通常被描述为包括三个步骤的机制：(1)在晶间界面上的溶解，(2)在两个晶粒之间的接触处溶质的扩散，以及(3)与孔隙流体接触的晶粒表面的沉淀。在本文中，我们提出了一个模型，我们在这个过程中增加了第四步，扩散输送到其他开放的孔隙，以解释孔隙流体中溶质的宏观扩散，从而使变形在晶粒尺度上不闭合。在该模型中，由于应力和粒度的变化，矿物溶解度的差异产生了驱动弥漫性质量传递的浓度梯度。晶粒尺度上的压力溶解与多个晶粒间的输运之间的相互作用会导致初始孔隙度非均质性的放大和随后的变形局部化。溶蚀作用强烈的区域与主要由胶结作用减少孔隙度的区域紧密相连并形成“带”。大规模扩散输运增加的压力解将导致质量从细粒岩石体向粗粒岩石体的输运。研究表明，这一过程在沉积物成岩作用和断层泥压实作用中都起着重要作用。索引项：3902矿物物理学：蠕变和变形；5114岩石物理性质：渗透率和孔隙度；8045构造地质学：流体的作用；8159构造物理学：地球演化：流变-地壳和岩石圈；引用本文：Gundersen， E.， F. Renard， D. K. Dysthe， K. Bjorlykke， B. Jamtveit，多孔岩石中压力溶液蠕变与弥散物质输运的耦合，地球物理学报。研究，107(0)，XXXX, doi:10.1029/ 2001jb000287,2002。
Received 29 September 2000; revised 25 January 2002; accepted 30 January 2002; published XX Month 2002. [1] Pressure solution is widely regarded as a mechanism of ductile deformation in the upper crust. It is driven by stress differences and its rate is affected by temperature, grain size, and fluid chemistry. Pressure solution involves dissolution at grain contacts under high stress and precipitation at grain contacts on pore surfaces under low stress, leading to porosity reduction by precipitation in the pore space or by grain indentation. For a system closed at a grain scale, pressure solution is traditionally described by a mechanism involving three steps: (1) dissolution at intergranular interfaces, (2) diffusion of solutes inside the contact between two grains, and (3) precipitation on the surface of the grains in contact with the pore fluid. In this paper we propose a model where we have added a fourth step to this process, diffusive transport to other open pores, to account for the macroscopic diffusion of solutes in pore fluids, such that the deformation is not closed at the grain scale. In this model, differences in mineral solubility due to variations in stress and grain size produce concentration gradients which drive diffusive mass transport. The interaction between pressure solution at a grain scale and transport over distances of several grains can lead to the amplification of initial porosity heterogeneities and subsequent localization of deformation. Regions of intense dissolution compact and form ‘‘bands’’ in close proximity to regions where the porosity reduction is mainly due to cementation. Pressure solution augmented by large-scale diffusional transport will cause mass transport from fine-grained to coarse-grained rock volumes. We show that such processes are important during both diagenesis of sediments and compaction of fault gouge. INDEX TERMS: 3902 Mineral Physics: Creep and deformation; 5114 Physical Properties of Rocks: Permeability and porosity; 8045 Structural Geology: Role of fluids; 8159 Tectonophysics: Evolution of the Earth: Rheology—crust and lithosphere; KEYWORDS: cementation, compaction, diagenesis, gouge, pressure solution, transport Citation: Gundersen, E., F. Renard, D. K. Dysthe, K. Bjorlykke, and B. Jamtveit, Coupling between pressure solution creep and diffusive mass transport in porous rocks, J. Geophys. Res., 107(0), XXXX, doi:10.1029/2001JB000287, 2002.