Fluid migration recorded by fluid inclusions in crack-sealed quartz veins and sandstone host rock; Cameros Basin, Spain

Abstract The role of deep hydrothermal fluid circulation through fractures and their impact on the sandstone host rock is studied in an extensional sedimentary basin (Cameros Basin, Spain) affected by a post-extensional metamorphism. quartzarenites Urbión Group constituted hydrocarbon carrier very low to low-grade metamorphism during Late Albian Coniacian. This process generated abundant quartz veins transformed into quartzites. study compares microthermometry inclusion asemblages (FIAs) grain overgrowths quartzites, order understand behavior fluids effects rock. Fluid inclusions contain liquid vapor at room temperature homogenize ( T h : 124–265 °C, H 2 O + NaCl system). Those present both CO aqueous phase (room temperature). Final homogenization 109–282 , mean values amount-of-substance fractions: 0.92, 0.01, 0.07). Large variation within each FIA common, due crack sealing processes reequilibration successive thermal pulses. In contrast, narrow range towards top record indicates that these are probably not reequilibrated. Two growing stages recognized under SEM-CL overgrowths, one diagenetic another hydrothermal, later with FIAs showing similar than veins. results can help evaluation geo-energy resources basins.