02392nab a2200229 4500 20260520000319.0 260224s2015 xxu ing Inglés Structural and chemical controls of deformation bands on fluid flow Interplay between cataclasis and diagenetic alteration abr. 2015 18/06/2015 ; 18/06/2015 21 p. ; 689-710 Transcripción del resumen del autor: We examined cataclastic shear bands (CSB) with varying degrees of deformation and alteration that formed in uncemented, arkosic sediments under identical kinematic conditions. The investigated outcrop in eastern Austria exposes numerous closely spaced sets of CSB formed at low burial depth. The uncemented host sediment consists of detrital quartz, albite, micas, and metamorphic lithoclasts. We distinguished three types of CSB, which differ in macroscopic and microscopic properties as well as in influence on fluid flow (i.e., single bands, multistrand bands, and band clusters). All band types show preferred fracturing of sericited albite grains and decomposition of biotite through mechanical deformation and subsequent chemical alteration. These mechanisms reduce the mean grain size, increase the amount of phyllosilicates in the matrix, and facilitate later growth of authigenic clay minerals. The dominant deformation mechanisms and influence on fluid flow are controlled by the initial composition and intensity of diagenetic alteration. We identified different evolutionary stages from a high-porosity host rock (BLTN13162eq1) to a deformation band cluster (BLTN13162eq2) that acts as fluid baffle. The measured reduction in porosity of up to 29% is reflected by retention of fluids along band clusters, along multistrand bands, and between intersecting bands. The timing and direction of the specific fluid flows can be determined by the interaction with the deformation bands. These findings suggest that localized deformation and associated diagenetic alteration in feldspar-bearing sediments may promote reservoir compartmentalization. 4 AAPG Bulletin 99 ARTICULO Lommatzsch, Marco 54528 Exner, Ulrike 51582 Gier, Susanne 54529 Grasemann, Bernhard 50735 188936 188936 0 0 0 0 256755 BAAB BAAB 2026-03-06 200061163 0 200061163 2026-03-06 00:19:02 2026-03-06 ARTICULO