Source Count: 14 | Weighted Score: 37 | Source Confidence: [4/5] | Primary Tier: 1 | Last Updated: April 10, 2026
Keywords: End-Triassic, Triassic-Jurassic, mass extinction, CAMP, Central Atlantic Magmatic Province, CO2, ocean acidification, dinosaurs, conodonts, ammonites, Pangaea, flood basalts
Category Tags: mass-extinction, triassic, jurassic, volcanism, flood-basalts, CO2, ocean-acidification, pangaea
Cross-References: E_5_02 — Ordovician Mass Extinction · E_4_27 — Chicxulub Impact K-Pg · E_1_17 — Toba Supereruption

QUICK SUMMARY

The End-Triassic mass extinction (c. 201.564 ± 0.015 million years ago) was one of the "Big Five" mass extinctions in Earth's history, eliminating approximately 76% of all species and ~50% of genera, clearing the ecological stage for the subsequent Jurassic dominance of dinosaurs. This extinction event is now firmly linked to the eruption of the Central Atlantic Magmatic Province (CAMP) — one of the largest known large igneous provinces (LIPs) in Earth's history, which produced over 10 million km³ of basaltic lava and volcanic gases as the supercontinent Pangaea began to rift apart, creating the embryonic Atlantic Ocean. CAMP lavas are preserved today across four continents — eastern North America (Newark Basin diabase sills, Palisades Sill), West Africa (Morocco, Mauritania), southwestern Europe (Iberia, France), and northeastern South America (Brazil, Guyana). KEY FINDING High-precision U-Pb zircon geochronology by Terrence Blackburn, Sam Bowring, and colleagues at MIT (published in Science, 2013) demonstrated that CAMP volcanism and the extinction boundary are synchronous to within ~20,000 years — the tightest temporal correlation between any LIP and mass extinction. The kill mechanisms were primarily atmospheric and oceanic: massive injections of CO₂ (estimated 8,000–40,000 Gt C) caused rapid global warming of 3–6°C, ocean acidification that devastated calcifying organisms, and probable episodes of ocean anoxia. Volcanic release of SO₂ caused short-term cooling and acid rain pulses between eruption phases. The extinction was catastrophic for marine life: conodonts went completely extinct (ending a 300-million-year lineage), most ammonite families disappeared, coral reefs collapsed, and bivalves and brachiopods lost many lineages. On land, several groups of crurotarsans (crocodile-line archosaurs) — including phytosaurs, aetosaurs, and rauisuchians — went extinct, removing the primary competitors and predators that had dominated Triassic terrestrial ecosystems. The surviving dinosaurs and their relatives then radiated explosively into the vacated ecological niches during the Early Jurassic. The End-Triassic extinction thus set the stage for the ~135-million-year "Age of Dinosaurs" that followed.

1. VERIFIED CLAIMS (Tier 1 — Peer-Reviewed / Established)

1.1 Extinction Magnitude and Timing

• The End-Triassic extinction (ETE) occurred at the Triassic-Jurassic (T-J) boundary, precisely dated to 201.564 ± 0.015 Ma by U-Pb zircon geochronology (Blackburn et al., 2013)
• Approximately 76% of species went extinct across marine and terrestrial ecosystems
• The event represents the fourth-most severe of the Big Five mass extinctions (after End-Permian, Late Devonian, and Late Ordovician)
• The Global Stratotype Section and Point (GSSP) for the base of the Jurassic (= the T-J boundary) is defined at Kuhjoch, Austria, marked by the first appearance of the ammonite Psiloceras spelae tirolicum

1.2 The Central Atlantic Magmatic Province (CAMP)

• CAMP is among the largest LIPs in Earth's history, covering an original area of at least 10 million km² (before continental drift separated the fragments)
• Total lava volume: estimated 2–3 million km³ of extruded basalt, with additional intrusive volume (sills, dikes) potentially doubling the total magmatic volume
• CAMP eruptions occurred in at least 4 main pulses over approximately 600,000 years, beginning just before the extinction boundary
• KEY FINDING Blackburn et al. (2013) showed that the oldest CAMP basalts (in Morocco and Nova Scotia) predate the extinction boundary by only ~20,000 years — establishing that volcanism preceded the extinction, consistent with a causal relationship
• CAMP lavas are preserved across four continents:
• North America: Palisades Sill (New Jersey/New York), Newark/Hartford basin flows
• Africa: High Atlas (Morocco), Argana Basin, Mauritania, Guinea
• South America: Maranhão Basin (Brazil), Guyana
• Europe: Algarve (Portugal), Pyrenees (France/Spain)

1.3 Key Victim Groups

• Conodonts: This ancient group of jawless vertebrates (or vertebrate relatives) went completely extinct at the T-J boundary, ending a lineage that had persisted for ~300 million years — one of the most significant total-group extinctions in the geological record
• Ammonites: Severe clade-wide devastation; the diverse Late Triassic ceratitid ammonites were wiped out; only a few lineages survived to diversify in the Jurassic
• Bivalves and brachiopods: Many families lost, particularly reef-associated and shallow-water taxa
• Scleractinian corals: Major reef collapse; Triassic reef ecosystems (which had developed the first modern-style coral reefs) were devastated
• Terrestrial vertebrates: Phytosaurs, aetosaurs, most rauisuchians, and several other crurotarsan clades went extinct. Some large temnospondyl amphibians also disappeared

1.4 Carbon Isotope Excursion

• A dramatic negative carbon isotope excursion (CIE) of ~6‰ in δ¹³C is recorded in both marine carbonates and terrestrial organic matter at the T-J boundary — indicating a massive injection of isotopically light carbon (consistent with volcanic CO₂, thermogenic methane from coal/organic matter intruded by CAMP sills, or methane hydrate dissociation)
• The CIE is documented at multiple sections worldwide: St. Audrie's Bay (UK), Kuhjoch (Austria), Newark Basin (USA), Queen Charlotte Islands (Canada)
• Hesselbo et al. (2002, Science) first documented the CIE in detail, establishing the link between carbon cycle perturbation and the extinction

2. CREDIBLE CLAIMS (Tier 2 — Academic / Debated but Supported)

2.1 CO₂-Driven Warming and Ocean Acidification

• CAMP volcanism released massive quantities of CO₂: estimates range from 8,000 to 40,000 gigatons of carbon (Gt C), depending on assumptions about intrusive degassing and thermogenic gas release from baked sediments
• Schaller et al. (2011, Science) used stomatal density of fossil leaves from the Newark Basin to estimate that atmospheric CO₂ levels doubled across each CAMP eruption pulse, from ~2,000 ppm to ~4,400 ppm
• CO₂ increase would cause: global warming (estimated 3–6°C), ocean acidification (reduced carbonate saturation state, dissolving calcareous shells), and changes in ocean circulation
• KEY FINDING The pattern of selectivity — with greatest losses among calcifying organisms (corals, brachiopods, bivalves, foraminifera) — is consistent with ocean acidification as a primary marine kill mechanism (Hautmann, 2004)

2.2 Mercury as a Volcanic Proxy

• Thibault et al. (2018) and Percival et al. (2017) documented elevated mercury (Hg) concentrations at the T-J boundary in multiple European sections, consistent with volcanic Hg emissions from CAMP eruptions
• Mercury anomalies are increasingly used as a proxy for LIP volcanism across geological time

2.3 SO₂-Driven Cooling Episodes

• Individual CAMP eruption pulses would have released massive amounts of SO₂, forming sulfate aerosols that reflect sunlight — producing short-term volcanic cooling ("volcanic winter") lasting months to years between eruption phases
• The alternation of warming (CO₂) and cooling (SO₂) episodes — "volcanism-induced climate whiplash" — may have been particularly devastating, preventing organisms from adapting to any single stable climate state

2.4 Dinosaur Ecological Release

• Before the ETE, crurotarsans (crocodile-line archosaurs: phytosaurs, rauisuchians, aetosaurs) were the dominant large terrestrial predators and herbivores in many Late Triassic ecosystems
• The extinction of crurotarsans and other competitors enabled dinosaurs (which were relatively small and ecologically marginal in the Late Triassic) to radiate into vacated niches
• Stephen Brusatte et al. (2010, Science) showed that dinosaurs and crurotarsans had comparable morphological diversity in the Late Triassic — dinosaurs did not outcompete their rivals; they simply outlasted them through the extinction

3. SPECULATIVE CLAIMS (Tier 3 — Possible but Unverified)

3.1 Bolide Impact Contribution

• The Manicouagan crater (Quebec, Canada, ~100 km diameter) was once considered a potential contributor to the End-Triassic extinction, but modern dating places it at ~215.5 Ma — approximately 14 million years too early for the T-J boundary
• Other candidate impact structures (e.g., Rochechouart, France, ~214 Ma) also predate the extinction
• No confirmed impact crater is currently dated to the exact T-J boundary. While an impact contribution cannot be entirely excluded, the available evidence overwhelmingly favors CAMP volcanism as the primary cause

3.2 Methane Hydrate Destabilization

• Researchers have proposed that CAMP-driven warming triggered the dissociation of methane hydrates (frozen methane in marine sediments), adding an additional pulse of greenhouse gas and amplifying the carbon isotope excursion
• The isotopic data (very negative δ¹³C values) are consistent with methane release, but direct evidence for hydrate destabilization at the T-J boundary is limited

4. DUBIOUS CLAIMS (Tier 4 — No Credible Source / Contradicted by Evidence)

4.1 Gradual Extinction Over the Entire Late Triassic

• DEBUNKED While there was some biodiversity decline during the Norian and Rhaetian stages of the Late Triassic, the main extinction pulse at the T-J boundary is geologically abrupt and coincides precisely with the onset of CAMP volcanism. Claims that the extinction was merely a gradual long-term trend are not supported by high-resolution biostratigraphic data

Counter-Arguments & Criticisms

Terrestrial vs. Marine Record

• The terrestrial extinction record is less well-constrained than the marine record due to the inherent incompleteness of the continental fossil record. Researchers argue that the apparently severe terrestrial extinction may be partly an artifact of sampling gaps in the latest Triassic

CAMP Timing Precision

• While the coincidence of CAMP and the extinction is well-established, the exact causal mechanism linkage (which gases, in what quantities, over what timescale) remains debated. Different CAMP eruption phases may have caused different environmental effects, and disentangling them requires higher-resolution records than are currently available for most sections

Selectivity Questions

• Not all groups with calcareous shells went extinct (some bivalve lineages survived well), raising questions about whether ocean acidification was truly the primary kill mechanism or whether other factors (temperature stress, anoxia, habitat loss) were equally important

IMAGES

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BIBLIOGRAPHY

1. Blackburn, Terrence J., et al | 2013 | "Zircon U-Pb Geochronology Links the End-Triassic Extinction with the Central Atlantic Magmatic Province" | Science | ∅ | 340.6135::941–945 | ∅ | ∅ | doi:10.1126/science.1234204 | ∅ | ∅ | ∅
2. Hesselbo, Stephen P., et al. . )030<0251:tameat>2.0.co; 2 | 2002 | "Terrestrial and Marine Extinction at the Triassic-Jurassic Boundary Synchronized with Major Carbon-Cycle Perturbation: A Link to Initiation of Massive Volcanism?" | Geology | ∅ | 30.3::251–254 | ∅ | ∅ | doi:10.1130/0091-7613(2002 | ∅ | ∅ | ∅
3. Schaller, Morgan F., James D | 2011 | "Atmospheric pCO₂ Perturbations Associated with the Central Atlantic Magmatic Province" | Science | ∅ | 331.6023::1404–1409 | Wright, and Dennis V | ∅ | doi:10.1126/science.1199011 | ∅ | ∅ | Kent
4. Hautmann, Michael | 2004 | "Effect of End-Triassic CO₂ Maximum on Carbonate Sedimentation and Marine Mass Extinction" | Facies | ∅ | 50::257–261 | ∅ | ∅ | doi:10.1007/s10347-004-0020-y | ∅ | ∅ | ∅
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6. Whiteside, Jessica H., et al | 2010 | "Compound-Specific Carbon Isotopes from Earth's Largest Flood Basalt Eruptions Directly Linked to the End-Triassic Mass Extinction" | Proceedings of the National Academy of Sciences | ∅ | 107.15::6721–6725 | ∅ | ∅ | ∅ | ∅ | ∅ | ∅
7. Percival, Lawrence M | 2017 | "Mercury Evidence for Pulsed Volcanism During the End-Triassic Mass Extinction" | Proceedings of the National Academy of Sciences | ∅ | 114.30::7929–7934 | E., et al | ∅ | ∅ | ∅ | ∅ | ∅
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9. Marzoli, Andrea, et al | 1999 | "Extensive 200-Million-Year-Old Continental Flood Basalts of the Central Atlantic Magmatic Province" | Science | ∅ | 284.5414::616–618 | ∅ | ∅ | ∅ | ∅ | ∅ | ∅
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12. Pálfy, József, et al | 2001 | "Carbon Isotope Anomaly and Other Geochemical Changes at the Triassic-Jurassic Boundary from a Marine Section in Hungary" | Geology | ∅ | 29.11::1047–1050 | ∅ | ∅ | ∅ | ∅ | ∅ | ∅
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CROSS-REFERENCE INDEX

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