File:Sedimentation of Pisco Formation at Sacaco sub-basin.png

English: Details of sedimentary structures and facies present in the Pisco Formation in the Sacaco sub-basin. a Outcrop view of the Pisco Formation at the Sud-Sacaco locality, showing typical irregular (erosive) bases, cross-stratification (xs) and parallel laminations (pl), bioturbation marks (B). b Close-up of herringbone cross-stratified (hcs) mid-to-coarse grained sandstones reflecting deposition in tidally influenced settings, interbedded with finely laminated diatomaceous beds. c Alternating levels of grey, olive and brownish mid-grained sandstone layers, showing irregular erosive bases (eb), convolute stratification (cs) and parallel laminations (pl). d Sedimentary structures similar to the ones shown in photo 5C, also showing local bioturbation (bt), large-scale cross-stratification (xs). e Close-up of sandstones showing hummocky cross-stratification (h-xs), typically formed on the shelf, close to the offshore transition zone. f Medium-grained grey sandstone package with symmetric wave-related current ripples, without bioturbation marks, typically occurring above the storm-wave base. g Rock exposure facing to west at the Yauca locality, showing massive to slightly bedded medium-grained sandstones with abundant bioturbation, overlaid by a prominent shell bank. h Close-up of intensively vertically bioturbated sandstones. i Massive tuffaceous sandstone (ts) to the base, irregularly passing to a medium-grained sandstone package with parallel laminations (pl), finishing upwards with a hardground surface with Fe staining, boring and intense burrowing towards the top. j Rock exposure showing regular intercalations of parallel to massive beds of grey medium-grained sandstones, intercalated with hardground surfaces (hg s) with boring and burrowing marks