Whole Earth Systems During Neoproterozoic Animal Evolution

ended

The late Neoproterozoic Era marks some of the most important changes in the biogeochemical evolution of our planet. During the late Cryogenian,Ediacaran and Early Cambrian Periods (ca. 650–520 Ma), our planet was marked by a global icehouse event (‘Snowball Earth’), a rapid rise in oxygen content of the atmosphere, evolution of animals and complex life forms and the amalgamation of the Gondwanian supercontinent, which formed the earliest ‘modern’ style mountain belts with the deep burial of continental crust resulting from massive continental-continental collisions. So far, biogeochemical modelling, geochemical analysis and general circulation climate models (GCMs) have linked all these key events to plate tectonic processes. However, there is yet to be a fully complete linked tectonic-biogeochemical-climate model, where geologically grounded parameters are passed directly into both biogeochemical and GCMs, principally because there is no full tectonic model of this time. Recent advancements in plate tectonic modelling have produced models that map the explicit kinematic evolution of plate boundaries and tectonic plates back to 1 Ga. Using this model as a foundation, I propose to construct secondary tectonic parameters (palaeobathymetry, palaeotopography, carbon flux) of the world between 650 and 520 Ma in order to act as a series of boundary conditions for a GCM and biogeochemical model. The GCM is constructed using the surface conditions from the tectonic parameters (palaeobathymetry, palaeotopography, continental positions) to produce surface temperature and hydrological estimates at key time intervals. These estimates, along with carbon flux estimates—calculated using the same plate model—are used to derive self-consistent biogeochemical cycles (e.g. O2, CO2, P cycles) which can then be evaluated against independent proxies from the geological record, allowing us to independently evaluate the impact of tectonic drivers on these pronounced global events.