Dawn of metazoans: to what extent was this influenced by the onset of “modern-type plate tectonics”?

Abstract

The appearance of complex megascopic multicellular eukaryotes in the Ediacaran occurred just when the dynamics of a cooling Earth allowed establishment of a new style of global tectonics that continues to the present as "modern-type plate tectonics". The advent of this style was first registered in 620 Ma-old coesite-bearing Ultra-High Pressure eclogites within the Transbrasiliano-Kandi mega-shear zone along the site of the West Gondwana Orogeny (WGO). These eclogites comprise the oldest evidence of slab-pull deep subduction capable of inducing continental collisions and producing high-relief Himalayan-type mega-mountains. Life, prior to this time, was essentially microscopic. Yet with increasing Neoproterozoic oxygenation and intensified influx of nutrients to Ediacaran oceans, resulting from the erosion of these mountains, complex macroscopic heterotrophic eukaryotes arose and diversified, taking the biosphere to a new evolutionary threshold. The repeated elevation of Himalayan-type mega-mountains ever since then has continued to play a fundamental role in nutrient supply and biosphere evolution. Other authors have alluded to the influence of Gondwana mountain-building upon Ediacaran evolution, however we claim here to have identified when and where it began.

Oxygen suppression of macroscopic multicellularity

“…The evolution of macroscopic multicellularity is a complex topic with no single causal agent 26 , 74 . Several macroevolutionary trends are becoming apparent, however.…”

Molecular dating of the blood pigment hemocyanin provides new insight into the origin of animals

“…The Neoproterozoic Era (1000–541 Ma) was characterized by significant modifications on the planet dynamics, including massive lithosphere alteration (Trindade et al, 2006); extreme glaciation events (Rooney et al, 2015; Spence et al, 2016); and the rise of atmospheric oxygen levels (Sperling et al, 2015; Tostevin & Mills, 2020). At least three great Neoproterozoic glaciations occurred, the extreme Sturtian (720–660 Ma) and Marinoan (650–636 Ma) ice ages and the more restricted, Gaskiers glaciation (582 Ma) (Cordani et al, 2020; Rooney et al, 2015; Spence et al, 2016). Our results indicate that the emergence of animal Hcs occurred prior to these extreme glaciation events that could suggest the presence of animals by this time.…”

Provenance study of Phanerozoic rocks from the Cordillera Real of Bolivia

“…In this sense, important relief was produced during the Brasiliano orogenic cycle, with the closure of the Goiás-Pharusian Ocean, along the Trans-Brazilian-Kandi lineament, a place where successive sutures and collisions occurred (Fig. 9, Cordani et al 2020). By that time, Gondwana had become almost completely assembled.…”

“…These probably reflect the recycling of magmatic and metamorphic rocks. Belts uplifted during 500 to 900 Ma along the Trans Brazilian-Kandi lineament (Cordani et al 2020) and/or the Pampean belts (Escayola et al 2011) could be the primary source of detrital zircons (Fig. 8).…”