Data for: What caused Earth's largest mass extinction event? New evidence from the Permian-Triassic boundary in northeastern Utah
This geochemistry data comes from a newly discovered extraordinarily well-preserved stratigraphic section of the Permian-Triassic boundary in Utah. The data features a comprehensive geochemical dataset from northeastern Utah, assembled from a unique and remarkable 9-meter section of rock in Sheep Creek Valley. The findings include a large-scale carbon isotopic excursion across the event, indicative of high atmospheric carbon dioxide, as well as a dramatic reduction in the deposition of calcium carbonate due to ocean acidification at the boundary layer. This study further documents an elevated mercury-spike, as well as observed elevated lead, zinc and strontium content. This evidence suggests large amounts of naturally occurring emissions of coal combustion at the Permian-Triassic boundary, likely caused by the large scale volcanic eruptions of the coeval Siberian Traps. The resulting global changes associated with the abrupt enrichment of the atmosphere in carbon dioxide was the major contributor to the mass extinction event. This is the first study to examine barium content across the Permian-Triassic boundary, and it provides evidence that upwelling of methane hydrate in the oceans followed the initial acidification event. Ocean anoxia (absence of oxygen) is suggested by the unusual deposition of pyrite within the shallow marine waters of the once coastal sediments of northeastern Utah. Precession orbital geochemical variation is observed in the stratigraphic section allowing a finer temporal resolution beyond any previously published section. Together, this dataset gives a unique picture of an ancient cataclysm that altered life on Earth.