Recovery from the end-Permian mass extinction is frequently described as
delayed(1-3), with complex ecological communities typically not found in
the fossil record until the Middle Triassic epoch. However, the
taxonomic diversity of a number of marine groups, ranging from ammonoids
to benthic foraminifera, peaked rapidly in the Early Triassic(4-10).
These variations in biodiversity occur amidst pronounced excursions in
the carbon isotope record, which are compatible with episodes of massive
CO2 outgassing from the Siberian Large Igneous Province(4,11-13). Here
we present a high-resolution Early Triassic temperature record based on
the oxygen isotope composition of pristine apatite from fossil
conodonts. Our reconstruction shows that the beginning of the Smithian
substage of the Early Triassic was marked by a cooler climate, followed
by an interval of warmth lasting until the Spathian substage boundary.
Cooler conditions resumed in the Spathian. We find the greatest
increases in taxonomic diversity during the cooler phases of the early
Smithian and early Spathian. In contrast, a period of extreme warmth in
the middle and late Smithian was associated with floral ecological
change and high faunal taxonomic turnover in the ocean. We suggest that
climate upheaval and carbon-cycle perturbations due to volcanic
outgassing were important drivers of Early Triassic biotic recovery.