Cyclostratigraphic calibration of the Famennian stage (Late Devonian, Illinois Basin, USA)

摘要: Abstract The Late Devonian biosphere was affected by two of the most severe biodiversity crises in Earth's history, Kellwasser and Hangenberg events near Frasnian–Famennian (F–F) Devonian–Carboniferous (D–C) boundaries, respectively. Current hypotheses for causes extinctions are focused on climate changes associated ocean anoxia. Testing these has been impeded a lack sufficient temporal resolution paleobiological, tectonic proxy records. While there have recent advances astronomical calibration that improved accuracy Frasnian time scale part Famennian, duration entire Famennian Stage remains poorly constrained. During Devonian, complete Frasnian–Early Carboniferous succession deep-shelf deposits accumulated epieric sea Illinois Basin central North-American mid-continent. A record this sequence is captured three overlapping cores (H-30, Sullivan H-32). H-30 core section spans F–F boundary; almost all H-32 sampled interval Upper D–C boundary. To best chance capturing Milankovitch cycles, 2000 rock samples were collected at minimum 5-cm-interval across sequence. Magnetic susceptibility (MS) measured each sample preservation climatic information into MS signal verified through geochemical analyses low-temperature magnetic acquisition. estimate Stage, we applied multiple spectral techniques tuned using highly stable 405 kyr cycle obliquity cores. Based correlation between constructed floating scale, which indicates 13.5 ± 0.5 myr. An uncertainty myr estimated uncertainties arising from errors stratigraphic position counting. Interpolated high-resolution U–Pb radiometric ages available boundary recalibrated numerical age to 372.4 0.9 Ma.