Carnian Pluvial Episode

18 Jul 2020

The word pluvial is usually associated with water - a watery environment. The Wranglia is a large igneous province that spewed out lots of greenhouse gases - or volcanic gases to be more exact. Climate shifted in association with the Wranglia, leading eventually to a warmer world that was wetter, and humid. This was the Carnian Pluvial Episode. So, we have a massive tectonic event and evidence of a watery landscape. Where might we have heard that before. See https://archaeologynewsnetwork.blogspot.com/2020/07/insights-into-climat... ... where it seems climate change is being rooted out in the oldest of geological records. This one goes back to the Triassic period and the evidence for the Carnian pluvial is in sediments - in a sub  division of the Triassic. Hence, no connection with the end of Permian or the end of Triassic events but another event spaced between the two. This is of course sediments dated to a uniformitarian slow rate of accumulation - so we might wonder. The  Carnian  Pluvial is marked by a layer of ash in lake sediments.. here we have some nice dinosaur footprints found in Argentina of the same period. The ash was dated by zircon crystals and it  is thought the South American site displays evidence of when the dinosaurs first evolved. That is of course open to question as footprints in the sediments suggest they had already evolved, possibly at the beginning of the Triassic.

The sediments consisted of clays and warm water based silt and sand. The Triassic came in with a bang and went out with a bang. Was it also subdivided by another bang?

There were of course several subdivisions to the Triassic and the Carnian is just one of them - see https://en.wikipedia.org/wiki/Carnian_Pluvial_Event .. which has a nice graph of the subdivisions handily positioned on the RH side of the web page. For more information on the Carnian Pluvial Episode go to https://jgs.lyellcollection.org/content/175/6/1019 ... or https://eprints.whiterose.ac.uk/90239/1/Carnian humidity final version.pdf 

For another version of the original story go to https://knowridge.com/2020/07/scientists-discover-an-unusual-time-called... ... or https://scitechdaily.com/carnian-pluvial-episode-revealed-climate-change...