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TitleMercury anomalies associated with three extinction events (Capitanian Crisis, Latest Permian, and the Smithian/Spathian) in NW Pangea
AuthorGrasby, S E; Beauchamp, B; Bond, D P G; Wignall, P B; Sanei, H
SourceGeological Magazine vol. 153, no. 2, 2015 p. 285-297,
Alt SeriesEarth Sciences Sector, Contribution Series 20150142
Mediapaper; on-line; digital
File formatpdf
Lat/Long WENS 9.0000 33.0000 81.0000 76.0000
Subjectsenvironmental geology; extinctions, biotic; mercury; mercury geochemistry; mercury injection; Latest Permian Extinction; Mercury; Early Triassic; Chemostratigraphy; LIP; Extinction Events; Permian Extinction; Hg Emission; Permian; Triassic
Illustrationslocation maps; tables; geochemical plots; stratigraphic cross-sections
ProgramShale Reservoir Characterization, Geoscience for New Energy Supply (GNES)
AbstractPermian through Early Triassic strata that include a record of three major extinction events (Capitanian Crisis, Latest Permian Extinction, and the Late Smithian Extinction) were examined at the Festningen section, Spitsbergen. Over the ~ 12 Ma record examined, mercury in the sediments shows relatively constant background values of 0.005 to 0.010 ?g/g. However, there are notable spikes in Hg concentration, over an order of magnitude above background, associated with the three extinctions. The Hg/TOC ratio shows similar large spikes, indicating that they represent true increase in Hg loading to the environment. We argue that these represent Hg loading events associated with enhanced Hg emissions from large igneous province (LIP) events that are synchronous with the extinctions. The Hg anomalies are consistent across the NW margin of Pangea, indicating widespread mercury loading occured. While this provides utility as a chemostratigraphic marker, the Hg spikes may also indicate loading of toxic metals to the environment that would be a contributing cause to the mass extinction events.
Summary(Plain Language Summary, not published)
Understanding global events that can cause deposition of shale gas units can enhance exploration efforts as well as resource characterisation. However, many shale gas intervals lack fossils traditionally used for establishing the age of the rocks, making it difficult to understand if the formation of 'fertile' shales in different sedimentary basins are related to global or local events. This study examined the novel application of mercury in the geologic record for use a new tool for stratigraphic correlation. Mercury is released periodically by large volcanic eruptions and leaves a marker the geological record as a mercury spike. We examined a 12 million year geologic record through important gas shale intervals and results show that defined mercury anomalies occur and can be used for regional trans-arctic correlations as well as to correlate with shale gas units in western Canada. These results suggest global events caused deposition of gas shales, allowing extrapolation into frontier areas to be made with greater certainty.