Paper No. 322-14
Presentation Time: 12:15 PM
RECORD OF END-PERMIAN AND EARLY TRIASSIC CRISIS FROM A HIGH-RESOLUTION SECTION IN EAST GREENLAND
The 252-Ma end-Permian mass extinction (EPME), which decimated marine and terrestrial biotas and which was linked to a major hyper thermal event, has been studied in detail in low-latitude Tethyan sections but not as much in high-latitude boreal regions. For this study, chemostratigraphic records for a ~600-m-thick composite section from Black Ridge West, Blue Elv and Nasutdal in east-central Greenland were generated. The section ranges from the late Changhsingian (Late Permian) to the mid-Dienerian (Early Triassic). The samples were deposited in a rapidly subsiding marine pull-apart basin that accumulated ~800 m of sediment in a period of ~1 million years. We were able to generate major- and trace-element concentration data for >600 samples over the span of the composite section, yielding an average temporal resolution of <2000 years per sample. Our results document a major change in lithology at the EPME horizon, marked by a dramatic increase in siliciclastics, a shift towards greater terrestrial chemical weathering intensity, the development of weakly reducing conditions, and possibly elevated marine productivity. Our observations of these high-latitude sites contrast with observations made at low-latitude Tethyan sites that exhibit evidence for a major productivity crash and more oxygenated conditions above the PTB (Algeo et al., 2013, Global and Planetary Change 105:52). The observations are consistent with an extreme warming event that commenced at the PTB and continued into the Early Triassic (Sun et al., 2012, Science 338:366; Romano et al., 2013, Nature Geoscience 6:57).