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Evidence record

What killed the dinosaurs?

Every sentence on the exploration belongs to at least one claim below. Each says what kind of statement it is, what it rests on, what the evidence does not establish, and how far it was checked. Nothing here is a score, and none of it is a verdict on a belief or a theory.

Last checked 24 September 2026.

  • A judgement, not a fact: 13
  • Source checked: 43
  • Partly checked: 3

If something here is wrong, misquoted, out of date or unfair, write to support@unknownoceans.com and give the claim number, which does not change.

What the question takes for granted

A question about the cause of a past event, answered from rock, fossils, dating and climate models. That the impact happened at the boundary is settled; how far the Deccan eruptions contributed is argued in the current literature.

  • The non-bird dinosaurs died out abruptly, at the end of the Cretaceous

    Established

    The review the page cites finds little support for a long global decline beforehand and reads the extinction as abrupt.

  • Birds are dinosaurs, so "the dinosaurs" means the ones that were not birds

    Established

    The page uses the word the way the review does.

  • One thing killed them

    Contested

    The question is singular; the answer the page gives is an impact with a volcanic province erupting across the same interval, and the share of each is argued.

How the question is labelled

Claim: Two catastrophes, one layer

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The title names the page’s problem: an impact at the boundary layer and a volcanic province erupting across it. The layer marks the impact; the eruptions span a longer interval around it.

Claim 1 · checked 24 September 2026 · AI-assisted audit

Claim: Extinction

Kind
Framing. Signposting. It asserts nothing a source could check.

The question

Claim: An asteroid hit, and lava was flooding across much of India in the same interval.

Kind
Historical claim. A statement about the past that historical evidence can test.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    On impact and volcanism across the Cretaceous-Paleogene boundaryIntroduction, p. 2

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Earth and its record · Review of the field

    The source reads: an estimated ~500,000 km3 of lava flooded across much ... of India and into the deep sea ... That both volcanism and the impact ... event occurred within several hundred thousand years of the K/Pg extinctions is beyond

What this does not establish

"The same interval" is a span of several hundred thousand years around the boundary, not a single moment.

Corrected

24 September 2026. Previously: “a volcanic province the size of France was erupting at the same time” No cited source gives the province’s area or compares it with France. Hull and others say the lava flooded across much of India, over several hundred thousand years rather than at one time.

Claim 3 · checked 24 September 2026 · AI-assisted audit

Claim: Sorting out which did what is still work.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

Follows from the 2020 paper, which lists the relative roles of impact and volcanism among the things still uncertain.

Claim 4 · checked 24 September 2026 · AI-assisted audit

Claim: The impact at Chicxulub is established, dated to the boundary layer,

Kind
What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review
Source checked. The cited passage was read, and it says this.

What this does not establish

The 2010 review gives the boundary as about 65.5 million years; the 2015 dating puts it at 66.043.

Later work looked for

Crossref, 2013 on, "Chicxulub impact age Cretaceous-Paleogene boundary": later work (Renne 2015, Hull 2020, both cited) keeps the impact at the boundary; nothing that changes it.

Claim 5 · checked 24 September 2026 · AI-assisted audit

Claim: and a 2010 review of the evidence concluded it triggered the extinction.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

Claim 6 · checked 24 September 2026 · AI-assisted audit

Claim: The Deccan eruptions were also underway.

Kind
Historical claim. A statement about the past that historical evidence can test.
Review
Source checked. The cited passage was read, and it says this.

Claim 7 · checked 24 September 2026 · AI-assisted audit

Claim: The remaining argument is about how much the volcanism contributed and whether the impact changed its behaviour.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    On impact and volcanism across the Cretaceous-Paleogene boundaryIntroduction, p. 2

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Review of the field

    The source reads: the potential ... relationship between impact and volcanism ... whether impact or volcanism acted ... as the sole, primary, or joint drivers of extinction

Claim 8 · checked 24 September 2026 · AI-assisted audit

Claim: Three quarters of species disappear at a single horizon in the rock, 66 million years ago,

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Mass Extinctions Through Geologic Time"End-Cretaceous Extinction"

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Earth and its record · Reference work

    The source reads: It is the closest to us today in time, occurring 66 million years ago. This extinction impacted both life on land and in the sea, with 76% of species, 40% of genera, and 17% of taxonomic families dying out.

  • Supports

    The Chicxulub Asteroid Impact and Mass Extinction at the Cretaceous-Paleogene Boundaryp. 1216

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Earth and its record · Review of the field

    The source reads: The bedding plane between the impact-ejecta-rich red clay layer and the under lying Cretaceous marls coincident with the abrupt mass extinction

What this does not establish

The species share is an estimate from a record counted mostly in genera and larger groups (see claim 31).

Later work looked for

Crossref, 2011 on, "magnitude end-Cretaceous mass extinction species loss": group-level studies, nothing that replaces the overall figure.

Claim 9 · checked 24 September 2026 · AI-assisted audit

Claim: and the horizon is thin.

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

What this does not establish

Thin far from the crater. Near it the deposit is metres to tens of metres thick, and the same review describes both.

Later work looked for

Describes a deposit Schulte and others map at more than 350 sites; not a finding later work revises.

Claim 10 · checked 24 September 2026 · AI-assisted audit

Claim: For a long time the problem was finding one cause big enough.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The page’s summary of the older debate, before the crater and the ejecta layer were tied together.

Claim 11 · checked 24 September 2026 · AI-assisted audit

Claim: The current problem is that there are two, and they overlap.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

Follows from the 2020 paper’s framing: a large impact and flood basalt volcanism near the same boundary.

Claim 12 · checked 24 September 2026 · AI-assisted audit

What is established

Claim: What is established

Kind
Framing. Signposting. It asserts nothing a source could check.

The impact happened and it was enormous

Claim: The impact happened and it was enormous

Kind
What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review
Source checked. The cited passage was read, and it says this.

Later work looked for

Crossref, 2016 on, "Chicxulub crater drilling peak ring": the IODP-ICDP drilling studies the crater further; nothing that changes it.

Claim 14 · checked 24 September 2026 · AI-assisted audit

Claim: A crater 180 to 200 kilometres across lies buried at the northern edge of the Yucatán peninsula, its centre just off the coast.

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

Later work looked for

Crossref, 2016 on, "Chicxulub crater diameter drilling": Hull and others (2020) give about 200 km; the range stands.

Corrected

24 September 2026. Previously: “lies buried under the Yucatán peninsula and offshore sediment” NASA’s description of the crater places its centre just off the coast; "offshore sediment" was not in any cited source.

Claim 15 · checked 24 September 2026 · AI-assisted audit

Claim: Its age matches the boundary layer to within the resolution of the dating.

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

Later work looked for

Crossref, 2013 on, "Chicxulub impact age Cretaceous-Paleogene boundary": nothing that separates the two.

Claim 16 · checked 24 September 2026 · AI-assisted audit

Claim: The boundary clay itself carries the signature worldwide: an excess of iridium, the anomaly that first pointed to an asteroid, shocked quartz, and glass droplets that were molten rock thrown into the air.

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    On impact and volcanism across the Cretaceous-Paleogene boundaryIntroduction, p. 2

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Earth and its record · Review of the field

    The source reads: boundary clay and include ... elevated abundances of siderophilic elements such as iridium, osmium, and nickel, and tektites

  • Supports

    The Chicxulub Asteroid Impact and Mass Extinction at the Cretaceous-Paleogene Boundaryp. 1214

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Earth and its record · Review of the field

    The source reads: the discovery of an anomalously high abundance of iridium and other platinum group elements (PGEs) in the K-Pg boundary clay led to the hypothesis that an asteroid

  • Supports

    The Chicxulub Asteroid Impact and Mass Extinction at the Cretaceous-Paleogene Boundaryabstract, p. 1214

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Earth and its record · Review of the field

    The source reads: a single ejecta-rich deposit compositionally linked to the Chicxulub impact is globally distributed at the Cretaceous-Paleogene boundary ... recognition of impact ejecta including spherules, shocked minerals, and Ni-rich spinels in many K-Pg boundary event deposits

Later work looked for

Crossref, 2013 on, "Chicxulub ejecta K-Pg boundary": further sites, nothing that changes it.

Corrected

24 September 2026. Previously: “iridium in quantities more typical of asteroids than of crust” The cited sources describe the iridium as anomalously high and as the finding that led to the asteroid hypothesis; none compares it with asteroid and crustal abundances.

Claim 17 · checked 24 September 2026 · AI-assisted audit

Claim: A review by forty-one researchers in 2010 concluded that the impact triggered the extinction,

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

Forty-one names are on the byline, counted.

Later work looked for

Crossref record search, 2010: three letters in Science in May 2010 (Archibald and others; Courtillot and Fluteau; Keller and others) disputed the review. Read only as records; the dispute is reported in the page’s second part.

Claim 18 · checked 24 September 2026 · AI-assisted audit

Claim: and that the pattern of who died agrees with what its modelled effects, darkness, cooling and the collapse of photosynthesis in the ocean, would do.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

What this does not establish

Agreement with modelled effects, as the review puts it, is not a demonstration that the impact alone was sufficient. The review itself says the relative importance of the different effects was still under scrutiny.

Corrected

24 September 2026. Previously: “and that its effects, darkness, cooling, and the collapse of photosynthesis in the ocean, are sufficient to explain the pattern of who died” The review claims agreement between the extinction pattern and modelled perturbations, not sufficiency; "sufficient" went further than its words.

Claim 19 · checked 24 September 2026 · AI-assisted audit

Claim: The event

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: 180 to 200 km

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

Later work looked for

Crossref, 2016 on, "Chicxulub crater diameter drilling": Hull and others (2020) give about 200 km; the range stands.

Claim 21 · checked 24 September 2026 · AI-assisted audit

Claim: Crater diameter

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: Buried under later limestone.

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

Later work looked for

A description of the setting; not a finding later work revises.

Claim 23 · checked 24 September 2026 · AI-assisted audit

Claim: At the surface it shows only as a shallow trough and an arc of sinkholes.

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Shaded Relief with Height as Color and Landsat, Yucatan Peninsula, Mexico (PIA03381)Description

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Earth and its record · Measurement

    The source reads: The pattern of the crater's rim is marked by a trough, the darker green semicircular line near the center of the picture. This trough is only about 3 to 5 meters (10 - 15 feet) deep ... would preferentially erode along the crater rim. This formed the trough as well as numerous sinkholes (called cenotes)

Later work looked for

A description of the surface; not a finding later work revises.

Corrected

24 September 2026. Previously: “found by oil exploration surveys before anyone was looking for it” No cited source describes how the crater was found. Replaced with what the NASA description of the site carries.

Claim 24 · checked 24 September 2026 · AI-assisted audit

Claim: 66 million

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

What this does not establish

The 2010 review the page also cites still used about 65.5 million years.

Later work looked for

Crossref, 2020 on, "Cretaceous-Paleogene boundary age": Kale and others (2025) use 66.05; nothing that moves it from 66.

Claim 25 · checked 24 September 2026 · AI-assisted audit

Claim: Years ago

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: Impact and boundary layer agree within the resolution of the best dating available.

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

Later work looked for

Crossref, 2013 on, "Chicxulub impact age Cretaceous-Paleogene boundary": nothing that separates the two.

Claim 27 · checked 24 September 2026 · AI-assisted audit

Claim: ~76%

Kind
Present-day figure. A count, survey or report finding, as the named source gives it.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Mass Extinctions Through Geologic Time"End-Cretaceous Extinction"

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Earth and its record · Reference work

    The source reads: with 76% of species, 40% of genera, and 17% of taxonomic families dying out

  • Context

    Has the Earth's sixth mass extinction already arrived?abstract

    Cited · Link answered, 19 October 2026 · Abstract only, 24 September 2026

    The source reads: Palaeontologists characterize mass extinctions as times when the Earth loses more than three-quarters of its species in a geologically short interval

What this does not establish

The Park Service page gives the figure without saying where it comes from or how it was reached. The 2011 paper the page cites was read only as its abstract, which gives the three-quarters threshold for mass extinctions in general, not this figure.

Later work looked for

Crossref, 2011 on, "magnitude end-Cretaceous mass extinction species loss": group-level studies, nothing that replaces the overall figure.

Claim 28 · checked 24 September 2026 · AI-assisted audit

Claim: Of species lost

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: Forty per cent of genera.

Kind
Present-day figure. A count, survey or report finding, as the named source gives it.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Mass Extinctions Through Geologic Time"End-Cretaceous Extinction"

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Earth and its record · Reference work

    The source reads: with 76% of species, 40% of genera, and 17% of taxonomic families dying out

What this does not establish

The page does not say which groups or which counts the figure comes from.

Later work looked for

Crossref, 2011 on, "magnitude end-Cretaceous mass extinction species loss": nothing that replaces it.

Corrected

24 September 2026. Previously: “Forty per cent of genera in the rock, converted to a species estimate by ratio.” The conversion method is in the body of the 2011 paper, which could not be read. Narrowed to what a readable source carries: the genus figure, and that extinction percentages are documented mostly above the species level.

Claim 30 · checked 24 September 2026 · AI-assisted audit

Claim: The fossil record is counted mostly in genera and larger groups,

Kind
What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    Mass Extinctions Through Geologic Timeintroduction

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Earth and its record · Reference work

    The source reads: studies of their taxa (especially genera, families, and higher levels) have allowed paleontologists to document the percentages of these groups that were impacted by extinction events

What this does not establish

The Park Service says this of marine invertebrates, the source of most of what is known about the five mass extinctions.

Later work looked for

How the record is counted; not a finding later work revises.

Claim 31 · checked 24 September 2026 · AI-assisted audit

Claim: so the species figure is the softer number.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The page’s reading of claim 31: a figure counted directly is firmer than one carried over to a level the record mostly does not count.

Claim 32 · checked 24 September 2026 · AI-assisted audit

Claim: Including every dinosaur that was not a bird, and more than nine in ten species of two main groups of chalky plankton.

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

The two groups are planktonic foraminifera and nannoplankton, which Hull and others treat together as the ocean’s floating calcifiers.

  • Supports

    Mass Extinctions Through Geologic Time"End-Cretaceous Extinction"

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Earth and its record · Reference work

    The source reads: causing dinosaurs (except for birds) to become extinct

  • Supports

    On impact and volcanism across the Cretaceous-Paleogene boundaryp. 9

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Earth and its record · Observational study: associations, not causes

    The source reads: the abrupt mass extinction of >90% planktonic ... foraminifera and 93% of nannoplankton species

  • Supports

    On impact and volcanism across the Cretaceous-Paleogene boundaryp. 9

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Earth and its record · Observational study: associations, not causes

    The source reads: fossil record of pelagic calcifiers

  • Supports

    The Chicxulub Asteroid Impact and Mass Extinction at the Cretaceous-Paleogene Boundaryp. 1218

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Earth and its record · Review of the field

    The source reads: There is a clear separation in extinction rate between strongly affected phytoplankton groups with calcareous shells and groups that had organic or siliceous shells.

Later work looked for

Crossref, 2016 on, "K-Pg plankton extinction selectivity": nothing that changes the figures.

Corrected

24 September 2026. Previously: “and most of the plankton in the surface ocean” The sources give species losses for two shelled groups, not for plankton as a whole; Schulte and others record a clear difference between shelled and unshelled groups.

Claim 33 · checked 24 September 2026 · AI-assisted audit

Claim: The northwest corner of the Yucatán peninsula, from Shuttle Radar Topography Mission elevation data.

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

Later work looked for

Describes the image; nothing to revise.

Claim 34 · checked 24 September 2026 · AI-assisted audit

Claim: The shallow trough and the sinkholes that trace the buried crater rim are how Chicxulub shows at the surface.

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

Later work looked for

Describes the image; nothing to revise.

Corrected

24 September 2026. Previously: “The shallow arc of sinkholes tracing the buried crater rim is the only part of Chicxulub visible from the surface.” NASA’s description names the trough as the surface expression of the rim, with the sinkholes along it; the caption had only the sinkholes, and called them the only visible part.

Claim 35 · checked 24 September 2026 · AI-assisted audit

The volcanism was also happening

Claim: The volcanism was also happening

Kind
Historical claim. A statement about the past that historical evidence can test.
Review
Source checked. The cited passage was read, and it says this.

Claim 36 · checked 24 September 2026 · AI-assisted audit

Claim: The Deccan Traps in India poured out between half a million and one and a half million cubic kilometres of lava across the same interval, depending on the estimate,

Kind
Present-day figure. A count, survey or report finding, as the named source gives it.
Review
Partly checked. Only part of the source could be read. What was not read is listed.

What this does not establish

The upper figure is from the abstract of a 2025 paper whose methods were not read. The two figures are estimates made in different ways, and the page gives the span rather than choosing.

Later work looked for

Crossref, 2020 on, "Deccan volcanism Cretaceous-Paleogene extinction timing": Kale and others (2025) recalculate the volume at about 1.5 million km3; page updated to give the span.

Corrected

24 September 2026. Previously: “The Deccan Traps in western India erupted hundreds of thousands of cubic kilometres of lava across the same interval,” Hull and others give about 500,000 km3 across the boundary chron and Kale and others (2025) about 1.5 million; "hundreds of thousands" sat below both, and the lava reached well beyond western India.

Claim 37 · checked 24 September 2026 · AI-assisted audit

Claim: releasing carbon dioxide and sulphur on a scale that affects climate.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    On impact and volcanism across the Cretaceous-Paleogene boundary"Marine environmental record of outgassing", p. 4

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Earth and its record · Model

    The source reads: Deccan Trap degassing released a mix of volatiles including sulfur dioxide (SO2), chlorine (Cl) ... and other halogens, and carbon dioxide (CO2), with sulfur having perhaps the greatest direct

  • Supports

    On impact and volcanism across the Cretaceous-Paleogene boundaryp. 5

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Earth and its record · Observational study: associations, not causes

    The source reads: marine and terrestrial records show a late Maastrichtian warming event of ~2°C on average

What this does not establish

The warming is measured; tying it to Deccan carbon dioxide rests on the paper’s carbon-cycle modelling.

Later work looked for

Crossref, 2020 on, "Deccan volcanism climate Cretaceous-Paleogene": Sinnesael and others (2024, record) find basalt weathering drew down carbon at the end of the warming; nothing that removes the climate effect.

Claim 38 · checked 24 September 2026 · AI-assisted audit

Claim: Dating published in 2015 found that the eruptions changed character close to the boundary, shifting to fewer and larger flows within about fifty thousand years of the impact,

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

What this does not establish

The timing of the Deccan eruptions against the boundary is disputed: the 2015 dating puts most of the lava after it, and a 2025 recalculation (read as an abstract) puts about seventy per cent before it.

Later work looked for

Crossref, 2020 on, "Deccan volcanism Cretaceous-Paleogene extinction timing": Kale and others (2025) contest where the lava falls against the boundary; the page reports that in its second part.

Claim 39 · checked 24 September 2026 · AI-assisted audit

Claim: and proposed that seismic energy from the impact may have provoked the change.

Kind
Hypothesis. A proposed explanation, not an established one.
Review
Source checked. The cited passage was read, and it says this.

What this does not establish

The paper says the timing is consistent with seismic triggering and that the mechanisms by which seismic events trigger volcanism are not understood in detail.

Claim 40 · checked 24 September 2026 · AI-assisted audit

Claim: So the two need not be independent candidates competing for the blame.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

Follows from the 2015 proposal (claim 40), which is stated as a possibility.

Corrected

24 September 2026. Previously: “So the two are not independent candidates competing for the blame.” The 2015 paper says the two may be related; the page stated as fact what it proposes.

Claim 41 · checked 24 September 2026 · AI-assisted audit

Claim: They may be one sequence.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The page’s gloss on the 2015 proposal, kept at "may".

Claim 42 · checked 24 September 2026 · AI-assisted audit

What is still argued

Claim: What is still argued

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: Two catastrophes at the same horizon is a harder problem than none.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The page’s own line between its two halves; it follows from claims 5 and 7.

Claim 44 · checked 24 September 2026 · AI-assisted audit

How much the eruptions contributed

Claim: How much the eruptions contributed

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: A 2020 analysis of climate records across the boundary found warming consistent with Deccan carbon release before the impact,

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

What this does not establish

The paper’s best-fitting scenario still puts about half the outgassing after the impact. The link from warming to Deccan carbon is made by modelling.

Later work looked for

Crossref, 2020 on, "Deccan volcanism Cretaceous-Paleogene extinction timing": Kale and others (2025) read the volcanism as the cause; the page now reports that side.

Claim 46 · checked 24 September 2026 · AI-assisted audit

Claim: and concluded that the extinction itself tracks the impact rather than the volcanism.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    On impact and volcanism across the Cretaceous-Paleogene boundaryabstract, p. 2

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Earth and its record · Model

    The source reads: with only impact ... coinciding with mass extinction and biologically amplified carbon cycle change

  • Supports

    On impact and volcanism across the Cretaceous-Paleogene boundary"No marine evidence for joint cause in mass extinction", p. 8

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Earth and its record · Observational study: associations, not causes

    The source reads: we found no evidence for elevated extinction rates in the latest Cretaceous in

What this does not establish

Marine records. The paper allows that later volcanism may have shaped the recovery.

Claim 47 · checked 24 September 2026 · AI-assisted audit

Claim: Others read the volcanism as the setup.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Partly checked. Only part of the source could be read. What was not read is listed.

What this does not establish

The 2025 paper was read as its abstract.

Corrected

24 September 2026. Previously: “Other groups read the same records as showing an ecosystem already under stress, in which case the impact finished something that was underway.” The dissent was unattributed and uncited, and "the same records" was not something any source said. Named who holds the other side, from a review the page already cites and a 2025 paper that argues the volcanic cause.

Claim 48 · checked 24 September 2026 · AI-assisted audit

Claim: A 2015 review of the dinosaur record allowed that Deccan climate change may have left communities less able to absorb the impact,

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

The same review holds that the impact was probably the fundamental cause of the dinosaur extinction.

  • Supports

    The extinction of the dinosaurssection VII(1), p. 638

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Review of the field

    The source reads: term Deccan-induced climate changes may have made latest Maastrichtian communities less resilient to the impact

Claim 49 · checked 24 September 2026 · AI-assisted audit

Claim: and a 2025 recalculation of the lava volumes put about seventy per cent of the lava before the boundary and argued that their gases set the stage for the extinction.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Partly checked. Only part of the source could be read. What was not read is listed.

What this does not establish

Read as the abstract; how the volumes were recalculated was not read. The 2015 dating the page cites put about seventy per cent of the volume after the shift near the boundary, the opposite way round.

Later work looked for

This is the newest work on the point found: Crossref, 2020 on, "Deccan volcanism Cretaceous-Paleogene extinction timing".

Claim 50 · checked 24 September 2026 · AI-assisted audit

Claim: The dating precision needed to settle this is at the edge of what the methods deliver.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

Later work looked for

Crossref, 2020 on, "Deccan volcanism Cretaceous-Paleogene extinction timing": the 2024 and 2025 papers still disagree on where the lava falls; nothing that settles it.

Claim 51 · checked 24 September 2026 · AI-assisted audit

Claim: Where the disagreement actually is

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: Agreed

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: A large asteroid struck at the boundary

Kind
What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review
Source checked. The cited passage was read, and it says this.

What this does not establish

One group argued the impact came about 300,000 years before the boundary; the 2010 review sets out that argument and rejects it.

Later work looked for

Crossref, 2013 on, "Chicxulub impact age Cretaceous-Paleogene boundary": nothing that moves the impact off the boundary.

Claim 54 · checked 24 September 2026 · AI-assisted audit

Claim: The Deccan Traps were erupting across the same interval

Kind
What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review
Source checked. The cited passage was read, and it says this.

Later work looked for

Crossref, 2020 on, "Deccan volcanism Cretaceous-Paleogene extinction timing": all later work places the eruptions across the boundary.

Claim 55 · checked 24 September 2026 · AI-assisted audit

Claim: The impact markers sit at the extinction horizon itself

Kind
What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review
Source checked. The cited passage was read, and it says this.

Later work looked for

Crossref, 2013 on, "Chicxulub ejecta K-Pg boundary": nothing that changes it.

Claim 56 · checked 24 September 2026 · AI-assisted audit

Claim: Argued

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: Whether the impact alone accounts for the extinction pattern

Kind
Disputed. A contested point, where the page reports a side or the disagreement.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

Other readings

The 2020 analysis finds the impact the primary driver; the 2015 dating paper holds that the extinctions probably resulted from both together.

Claim 58 · checked 24 September 2026 · AI-assisted audit

Claim: Whether the volcanism had already weakened ecosystems

Kind
Disputed. A contested point, where the page reports a side or the disagreement.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

  • Context

    On impact and volcanism across the Cretaceous-Paleogene boundaryp. 8

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026

    The source reads: we found no evidence for elevated extinction rates in the latest Cretaceous in

  • Context

    The extinction of the dinosaurssection VII(1), p. 638

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026

    The source reads: term Deccan-induced climate changes may have made latest Maastrichtian communities less resilient to the impact

Other readings

The 2020 analysis finds no marine sign of it; the 2015 dinosaur review allows it; the 2025 volume study (claim 50) argues the eruptions set the stage.

Claim 59 · checked 24 September 2026 · AI-assisted audit

Claim: Whether the impact altered the eruptions

Kind
Disputed. A contested point, where the page reports a side or the disagreement.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

Other readings

Proposed by the 2015 dating paper; the 2020 analysis lists it among open questions, and the 2025 volume study puts most of the lava before the impact.

Claim 60 · checked 24 September 2026 · AI-assisted audit

Claim: How much of the boundary warming belongs to which cause

Kind
Disputed. A contested point, where the page reports a side or the disagreement.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

Other readings

The 2020 analysis gives the warming before the boundary to Deccan carbon, and reads an apparent sharp warming after it in fish teeth as a change in the fish rather than in temperature; that reading is its own.

Claim 61 · checked 24 September 2026 · AI-assisted audit

Why some lineages survived

Claim: Why some lineages survived

Kind
Framing. Signposting. It asserts nothing a source could check.

Claim: Birds are dinosaurs,

Kind
What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    The extinction of the dinosaurssection I, Introduction, p. 629

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Review of the field

    The source reads: are direct evolutionary descendants of non-avian dinosaurs, and therefore living dinosaurs

Later work looked for

A matter of classification the field has held since before the review; nothing that changes it.

Claim 63 · checked 24 September 2026 · AI-assisted audit

Claim: and only one branch of them, the lineage of modern birds, came through.

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    The extinction of the dinosaurssection VII(2), p. 638

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Earth and its record · Review of the field

    The source reads: many organisms living alongside dinosaurs also went extinct, including non-neornithine birds

What this does not establish

The review names the surviving group as the neornithine birds; "modern birds" is the page’s rendering of that name.

Later work looked for

Crossref, 2014 on, "avian extinction end of the Cretaceous": later work studies which neornithines survived; nothing that changes it.

Corrected

24 September 2026. Previously: “and one branch of them came through. Most bird lineages did not,” The review records the extinction of the non-neornithine birds; "most bird lineages" was a count no cited source makes.

Claim 64 · checked 24 September 2026 · AI-assisted audit

Claim: Many lizards, snakes and crocodile relatives died too.

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    The extinction of the dinosaurssection VII(2), p. 638

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Earth and its record · Review of the field

    The source reads: many lizards and snakes (Longrich, Bhullar & Gauthier, 2012), pterosaurs, and numerous crocodyliforms

Later work looked for

Crossref, 2016 on, "K-Pg extinction selectivity": nothing that changes it.

Claim 65 · checked 24 September 2026 · AI-assisted audit

Claim: Freshwater amphibians and turtles lost less, and every group of mammals was hit hard.

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    The extinction of the dinosaurssection VII(2), p. 638

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Earth and its record · Review of the field

    The source reads: Conversely, aquatic freshwater tetrapods such as amphibians, turtles, and choristodires experienced lower losses

  • Supports

    The extinction of the dinosaurssection VII(2), p. 638

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Earth and its record · Review of the field

    The source reads: All mammal groups were severely affected by the end-Cretaceous extinction

Later work looked for

Crossref, 2016 on, "K-Pg extinction mammals survival": nothing that changes it.

Corrected

24 September 2026. Previously: “Amphibians, turtles and small mammals came through in better shape.” The review says all mammal groups were severely affected, the larger-bodied most; mammals did not come through in better shape.

Claim 66 · checked 24 September 2026 · AI-assisted audit

Claim: Among mammals, the larger-bodied and the specialised feeders fared worst,

Kind
Observation. Something measured or seen, as the named source reports it.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    The extinction of the dinosaurssection VII(2), p. 638

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Earth and its record · Review of the field

    The source reads: particularly metatherians (marsupials and their fossil relatives) ... larger-bodied species, and those with specialized diets

    Notation restored: Word spaces restored: the PDF’s text extraction ran “and those with specialized diets” together. The letters are unchanged; not checked against a rendered copy, because none could be reached. The text as extracted reads: particularly metatherians (marsupials and their fossil relatives) ... larger-bodied species,andthosewithspecializeddiets

Later work looked for

Crossref, 2016 on, "K-Pg extinction mammals survival": nothing that changes it.

Corrected

24 September 2026. Previously: “Small body size, an unspecialised diet,” The review reports body size and diet for mammals only; the page had generalised them to every lineage.

Claim 67 · checked 24 September 2026 · AI-assisted audit

Claim: and life in fresh water appears to have helped.

Kind
What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    The extinction of the dinosaurssection VII(2), p. 638

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Earth and its record · Review of the field

    The source reads: There is general agreement that organisms in freshwater ecosystems were less affected by the extinction than those in terrestrial (non-aquatic) or marine environments

Later work looked for

Crossref, 2016 on, "K-Pg extinction selectivity": nothing that changes it.

Claim 68 · checked 24 September 2026 · AI-assisted audit

Claim: One explanation offered for the freshwater advantage is food chains running on detritus rather than on sunlight.

Kind
Hypothesis. A proposed explanation, not an established one.
Review
Source checked. The cited passage was read, and it says this.

What this does not establish

Both reviews offer it as a likely reason, not a demonstrated one.

Corrected

24 September 2026. Previously: “and the freshwater advantage is usually read as food chains running on detritus rather than on sunlight” The review says "possibly because"; "usually read as" claimed a standing no source gives it.

Claim 69 · checked 24 September 2026 · AI-assisted audit

Claim: The pattern is suggestive rather than explained.

Kind
This page’s reading. A judgement the page makes from the evidence. Others read it differently.
Review
A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.

The page’s summary of claims 66 to 69, where the explanations offered are stated as possible.

Claim 70 · checked 24 September 2026 · AI-assisted audit

Claim: A 2015 review listed why certain birds survived, while many bird-like feathered dinosaurs died, among the questions for the decade ahead.

Kind
What scholars argue. A report of what specialists argue, or where they disagree.
Review
Source checked. The cited passage was read, and it says this.

  • Supports

    The extinction of the dinosaurssection VII(3), "Future directions", pp. 638-639

    Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Review of the field

    The source reads: We identify the following as critical research objectives for the next decade ... survived whereas many bird-like feathered dinosaurs died off

Corrected

24 September 2026. Previously: “Selective survival at a mass extinction is one of the least well understood parts of the record.” No cited source ranks selective survival among the least understood parts of the record. Narrowed to what the review says.

Claim 71 · checked 24 September 2026 · AI-assisted audit

What was read