File:Pisco Formation sediment deformations.png

English: Soft-sediment deformation structures. Soft-sediment deformation structures associated with vertebrate skeletons from various localities and horizons of the Pisco Formation. These deformation features are interpreted to have formed around vertebrate carcasses that partially sank into the sediment. Note the presence of a yellow-black-red (YBR) sequence around both skeletons. A, B) Field photograph (A) and corresponding line drawing (B) of CCM28, skeleton of Cetotheriidae indet. from P1 diatomaceous silts exposed at Cerro Colorado, preserved in ventral disposition, exhibiting a high degree of articulation and a moderately high degree of completeness (4,3). The white box in panel A indicates the area detailed in panel E. C, D) Field photograph (C) and corresponding line drawing (D) of specimen CLQM58, skeleton of Mysticeti indet. from P2 diatomites exposed at Cerro los Quesos East, preserved in dorsal disposition, exhibiting high degrees of articulation and completeness (4,4). The dorsal disposition and articulation and completeness values of CLQM58 suggest it sank back-first onto the seafloor, kicking up soupy sediment that engulfed it. E) Close up of the deformed diatomaceous silt laminae around CCM28. Arrows point to deformed laminae gently dipping towards the skeleton. F) Detail of the distorted diatomite laminae underlying the cranium of CLQM58 (cross section through the entombing sediment). Note the YBR (yellow-black-red) sequence passing across both the deformed laminae (white lines) and a small-scale fault (red line) indicating that soft-sediment deformation occurred shortly after deposition and prior to the establishment of the early diagenetic reduced conditions induced by carcasses degradation. Panel C after Gariboldi et al. 2015.