Fault baffle to conduit developments: reactivation and calcite cementation of deformation band fault in aeolian sandstone

Abstract

The damage zone of three small faults in the Navajo and Page formations, located on the NE side of San Rafael Swell, Utah, USA, are studied. Scanlines and microstructural analyses are used to document three distinct deformation events: (1) an early phase creating cataclastic deformation bands, during which most of the displacement on the fault took place; (2) a fracturing event with opening and shearing along fractures; and (3) fluid flow and local calcite precipitation along the NW-trending faults. Microstructural characterization of deformation structures shows complex interaction between deformation bands, fractures and the calcite precipitation. Calcite cement is observed as veins in the host rock and along cataclastic bands, with varying amount of cataclastic material floating within the veins. In addition to patchy calcite cement in the host rock, extensive poikilotopic cementation is observed to extend into cataclastic bands with a low degree of cataclasis. However, some cataclastic bands with a high degree of cataclasis show almost no cementation. Development of deformation bands and their link to fracturing affected the flow field, from a fault baffle to a conduit. Calcite cementation reveals the flow paths, before cementation recreated the fault baffle.

Analysis of deformation bands associated with the Trachyte Mesa intrusion, Henry Mountains, Utah: implications for reservoir connectivity and fluid flow around sill intrusions

“…In contrast, cataclastic bands will also reduce the local permeability by two, or more, orders of magnitude (Ballas et al, 2015), but may also significantly impede flow due to additional fabric anisotropy, forming barriers (e.g. and significantly impacting flow pathways (Taylor and Pollard, 2000;Soliva et al, 2013). Therefore, in addition to the topological variations outlined in Fig.…”

“…Deformation bands can develop in most structural and tectonic settings, provided the host rock is susceptible to their formation Schultz et al, 2010;Soliva et al, 2013;Ballas et al, 2015). Deformation bands within quartz arenite to arkosic sandstones (i.e.…”

The growth of faults and fracture networks in a mechanically evolving, mechanically stratified rock mass: a case study from Spireslack Surface Coal Mine, Scotland

“…5, 6) may act as a baffle or barrier to flow (e.g. Skurtveit et al, 2015). It is therefore more appropriate to consider the "joint network" when assessing the modern-day network connectivity at the site.…”

“…Veins are often associated with faulting, providing evidence of the paleo-fluid flow through a fracture network (Bons et al, 2012;Oliver and Bons, 2001;Peacock and Sanderson, 2018) and may act as a baffle to post-cementation basinal fluid flow (e.g. Skurtveit et al, 2015). Additionally, the strength of a rock mass can vary depending on the strength ratio between the host-rock and veins, along with the mineralogy, thickness, and orientation of veins relative to the maximum compressive stress (e.g.…”

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“…Dilational fracture systems can, however, significantly enhance fluid flow capacity in hydraulic seals (e.g., Sibson, 1990Dehandschutter et al, 2005Gale et al, 2014;Rutter et al, 2017;Yarushina, 2018), and the mapping of fracture systems is therefore crucial in the evaluation of caprock integrity (e.g., Horsrud et al, 1998;Nelson, 2001;Ross & Boustin, 2008;Loucks et al, 2009;Skurveit et al, 2012;Gale et al, 2014;Ougier-Simonin et al, 2016), and has gained some attention in connection with carbon sequestration (Carbon capture and storage; CCS) (Makurat et al, 1992;Luo & Vasseur, 1997;Camac et al, 2009;Halland et al, 2011;Skurtveit et al, 2012Skurtveit et al, , 2015bYarushima, 2018), in connection with the production of shale gas (e.g., Hill & Nelson, 2000;Curtis 2002;Ladéveze et al, 2018), and in the containment of radioactive waste (Green, 1988;Harrington et al ,2017).…”