A new paper:
=================
Highlights
Precise UPb age constrains Carnian Pluvial Event (CPE) interval in Argentina.
We provide the first multiproxy paleoclimate data for the CPE in Gondwana.
Unclear linkage between CPE and dinosaur diversification with current evidence.
Abstract
The Triassic hothouse world experienced dynamic changes in climate and ecosystems that set the Earth's climate and biotic states for part of the Mesozoic Era. A critical time interval was the Carnian Stage (~237â227âMa), which not only saw the first appearance of dinosaurs in the fossil record but witnessed a large igneous province (Wrangellia LIP) and a sudden climate shift, the Carnian Pluvial Episode (CPE). Compelling hypotheses suggest that the Wrangellia eruptions caused the CPE, which in turn set the stage for the origin and initial diversification of dinosaurs. Unfortunately, testing these hypotheses is difficult because most relevant Carnian sedimentary archives possess few if any absolute age constraints, and there is little detailed paleoclimatic data for the CPE outside of the Tethys region. There is little existing evidence for the CPE in Gondwana, even though this region contains by far the best fossil record of early dinosaurs and their close relatives. We present new high-resolution geochronologic and paleoclimatic data from Carnian-aged strata in the Ischigualasto-Villa UniÃn Basin of northwest Argentina, which also preserves fossils of the earliest-known dinosaurs. New CA-TIMS UPb zircon age of 234.47âÂâ0.44âMa from the lower Los Rastros Formation demonstrates that most of the overlying lacustrine strata within this basin was deposited during or after the CPE, including large dinosauriforms fossil footprint. Multiproxy paleoenvironmental data (sedimentology, clay mineralogy, C and O stable isotopes, and fossils) from the same strata are the first detailed paleoclimate data for the CPE in Gondwana, and provide evidence that the CPE interval in western Gondwana was indeed warmer and more humid than before or after. These data are consistent with the interpretation of the CPE as a global event, but direct linkages in Gondwana and the Tethys with the origin and initial diversification of dinosaurs are less clear.