Detrital Clay Coats, Clay Minerals, and Pyrite: A Modern Shallow-Core Analogue For Ancient and Deeply Buried Estuarine Sandstones

• DOI: 10.2110/jsr.2018.56
• Publication Date: 2018-10-25T04:47:05Z
• Authors: Joshua Griffiths; Richard H. Worden; Luke J. Wooldridge; James E. P. Utley; Robert A. Duller
• Keywords: Authigenic; Illite

The spatial distribution of clay minerals and authigenic-clay-coated sand grains in ancient deeply buried petroleum reservoirs, which can enhance or degrade reservoir quality, is poorly understood. Authigenic coats are reported to originate from the thermally driven recrystallization detrital through situ growth authigenic alteration precursor early-diagenetic during burial diagenesis. To help predict estuarine sandstones, this study provides first modern-analogue study, using Ravenglass Estuary, UK, integrates patterns lithofacies, Fe-sulfide, detrital-clay-coats clay-minerals. X-ray-diffraction-determined mineralogy extent clay-coat coverage sediment twenty-three one-meter cores was established, at an unprecedented high resolution. output shows that mineral controlled principally by physical sorting grain size. Chlorite most abundant coarser-grained (e.g., low-amplitude dunes), whereas illite finer-grained sub-environments mud flats). Kaolinite abundance relatively homogeneous, smectite negligible Estuary. This has shown clay-minerals processes active deposition bio-sediment interaction top few millimeters primary environment. In have not been overprinted postdepositional bioturbation mechanical infiltration. Optimum detrital-clay-coat mineralogy, might serve as a porosity-preserving sandstone likely occur dunes inner estuary central basin. Furthermore, reduced Fe-sulfide due oxidization, meaning iron remains available for formation Fe-bearing minerals, such chlorite, lead enhanced quality sandstones.