Zircon U-Pb Geochronology Links the End-Triassic Extinction with the Central Atlantic Magmatic Province

Abstract

The end-Triassic extinction is characterized by major losses in both terrestrial and marine diversity, setting the stage for dinosaurs to dominate Earth for the next 136 million years. Despite the approximate coincidence between this extinction and flood basalt volcanism, existing geochronologic dates have insufficient resolution to confirm eruptive rates required to induce major climate perturbations. Here, we present new zircon uranium-lead (U-Pb) geochronologic constraints on the age and duration of flood basalt volcanism within the Central Atlantic Magmatic Province. This chronology demonstrates synchroneity between the earliest volcanism and extinction, tests and corroborates the existing astrochronologic time scale, and shows that the release of magma and associated atmospheric flux occurred in four pulses over about 600,000 years, indicating expansive volcanism even as the biologic recovery was under way.T he approximate temporal coincidence between the five major extinction events over the past 542 million years and the eruption of large igneous provinces (LIPs) has led to speculation that environmental perturbations generated by the emplacement of large volumes of magma and associated outgassing over short periods of time triggered each global biologic crisis (1). Establishing an exact link between extinctions and LIP eruptions has proved difficult because of the geographic separation between LIP volcanic deposits and stratigraphic sequences preserving evidence of the extinction. In most cases, uncertainties on radioisotopic dates used to correlate between geographically separated study areas exceed the duration of both the extinction interval and LIP volcanism by an order of magnitude. This hinders evaluation of any relationship between magmatism and extinction and precludes accurate estimates of volcanic effusion rates, associated volatile release, and extinction mechanisms.The end-Triassic extinction (ETE)-marked within early Mesozoic basins of eastern North America by a dramatic turnover in fossil pollen, spores (sporomorphs), and vertebrates (2)-is one of the largest Phanerozoic mass extinctions, occurring just before the Triassic-Jurassic boundary (3, 4), and has long been thought to be associated with the eruptions of the Central Atlantic Magmatic Province (CAMP) (5, 6). CAMP is the most aerially extensive LIP on Earth, and with volume estimates between 2-3 × 10 6 km 3 , it ranks as one of the most voluminous (7) (Fig. 1). Remnants of CAMP are found on four continents and consist primarily of continental thoeliitic basalts emplaced as subaerial flows and intrusive bodies during rifting of the Pangean supercontinent and incipient formation of the Atlantic Ocean basin (Fig. 1) fig. S1) prevents estimation of the volume of magma erupted over unit time, a critical factor for evaluating extinction mechanisms such as CO 2 -induced global warming (12, 13) ocean acidification (14, 15), or sulfur aerosol-induced "volcanic winters" (16). U-Pb Geochronology of CAMP Flows and IntrusivesHere, we present zirco...

High-precision timeline for Earth’s most severe extinction

“…The end-Permian extinction event occurred suddenly and rapidly (61 ± 48 ka) in an interval much shorter than current estimates for the total duration of Siberian Traps magmatism, suggesting that, similar to the end-Triassic extinction event, a single pulse of magmatism may be the most critical for triggering dramatic environmental change (43,47,48). Current U-Pb and Ar-Ar constraints on the timing and tempo of Siberian Traps magmatism are less precise by an order of magnitude than our new constraints on the extinction.…”

Aberrant Classopollis pollen reveals evidence for unreduced (2 n ) pollen in the conifer family Cheirolepidiaceae during the Triassic–Jurassic transition

“…We suggest that similar to aberrant lycophyte spores [48] and conifer pollen [49], during the end-Permian mass extinction aberrant Classopollis pollen may indicate environmental mutagenesis during the end-Triassic mass extinction. Extensive volcanism of the Central Atlantic magmatic province during the Triassic-Jurassic transition is generally viewed as a trigger mechanism of this global biotic crisis by extreme climate transitions [50]. Evidence for rapid climate cooling followed by extreme warming comes from geochemical proxy [51] as well as biological proxy records [52].…”

A triász és a jura időszak határán lezajlott globális krízis és annak nyomai magyarországi rétegsorokban

“…MARZOLI et al (1999) kormeghatározásai mutattak rá a Közép-Atlanti mag más provincia (KAMP) hatalmas kiterjedésére, ami a tengeri rétegsorokban definiált triász-jura határ korával jó egyezést mutatott (PÁLFY et al 2000). A mind pontosabbá váló U-Pb kormeghatározások megerősítették a tengeri kiha lás (SCHOENE et al 2010) és a vulkanizmus (BLACKBURN et al 2013) időbeli egyezését. A vulkáni kigázosodás mérté -két újszerű geokémiai vizsgálatok is alátámasztják (CALLEGARO et al 2014), valamint a légköri szén-dioxid szintjének megugrását is mind megbízhatóbban ismerjük (STEINTHORSDOTTIR et al 2011).…”