The Furongian (late Cambrian) Steptoean Positive Carbon Isotope Excursion (SPICE) in Avalonia

Decoupling biogeochemical records, extinction, and environmental change during the Cambrian SPICE event

Several positive carbon isotope excursions in Lower Paleozoic rocks, including the prominent Upper Cambrian Steptoean Positive Carbon Isotope Excursion (SPICE), are thought to reflect intermittent perturbations in the hydrosphere-biosphere system. Models explaining these secular changes are abundant, but the synchronicity and regional variation of the isotope signals are not well understood. Ex...

Paired positive carbonate carbon isotope, organic carbon isotope, and oxygen isotope composition study across the Lower Mississippian positive carbon isotope excursion, southeastern Nevada, USA

Pulse of atmospheric oxygen during the late Cambrian.

A rise in atmospheric O(2) has been linked to the Cambrian explosion of life. For the plankton and animal radiation that began some 40 million yr later and continued through much of the Ordovician (Great Ordovician Biodiversification Event), the search for an environmental trigger(s) has remained elusive. Here we present a carbon and sulfur isotope mass balance model for the latest Cambrian tim...

Enigmatic origin of the largest-known carbon isotope excursion in Earth's history

285 The global carbon cycle is the biogeochemical engine at the heart of acid–base and redox processes in the oceans and atmosphere. It constitutes the most fundamental way in which the biosphere shapes the chemistry of our planet. Studying the behaviour of the carbon cycle during times past, however, presents unique challenges. On geological timescales, the CO2 emitted from volcanoes and the w...

Carbon Isotope Excursion in Atmospheric CO2 at the Cretaceous-Tertiary Boundary: Evidence from Terrestrial Sediments

A 1.5‰ to 2‰ carbon isotope excursion immediately above the clay layer that defines the Cretaceous-Tertiary (K/ T) boundary has been reported in marine sediments world wide. This paper reports a similar 1.5‰ to 2.8‰ carbon isotope excursion recorded by C3 land plants from three temporally-controlled, stratigraphically-constrained terrestrial sections in the Western Interior of North America (Ga...