Multicellular animals probably evolved at the seafloor after a rise in oceanic oxygen levels. In 2013, Graham Shields-Zhou and his Chinese colleague Maoyan Zhu proposed that when these animals began to rework (bioturbate) the seafloor for the first time close to the Precambrian-Cambrian boundary, they triggered a negative feedback that reduced and stabilised global atmospheric and ocean oxygen levels. More...
The Ainsa Deepwater Channel Project, Spanish Pyrenees
An Integrated Outcrop Study: Project Manager: Professor Kevin T. Pickering
Introduction to the Ainsa Channel System
The Ainsa Channel System, south-central Pyrenees, occurs in the oldest part of the Campodarbe Group, and it is of Upper Eocene age. The Ainsa Channel Complex is per- haps the most famous of the submarine channel outcrops within Western Europe. The Ainsa channels consist of two principal channel complexes (Ainsa I and Ainsa II) which are separated by thin- and very thin-bedded sandy turbidites and marls. The Ainsa I Channel Complex is an example of an erosional-depositional system. The Ainsa II Chan- nel Complex contains significant erosional cut-downs, with infill of essentially non- erosive sandy facies. The channel dimensions are at a seismic scale.