Evidence from crater ages for periodic impacts on the Earth

@article{Alvarez1984EvidenceFC,
  title={Evidence from crater ages for periodic impacts on the Earth},
  author={Walter Alvarez and Richard A. Muller},
  journal={Nature},
  year={1984},
  volume={308},
  pages={718-720}
}
Recent evidence has indicated that the impact of a comet or asteroid may have been responsible for mass extinction at the ends of both the Cretaceous1 and the Eocene2–4. Quantitative analysis by Raup and Sepkoski5 showed that mass extinctions occur with a 26-Myr period, similar to the period seen in qualitative pelagic records by Fischer and Arthur6. To account for the possibility of periodic comet showers, Davis et al.7 proposed that such showers could be triggered by an unseen solar companion… 

Terrestrial impactors at geological boundary events: comets or asteroids?

Evidence has been presented1,2 for a 26–28-Myr periodicity in both the terrestrial extinction record and the age of large well-dated impact craters on the Earth. A cometary source controlled by

Extinction of species by periodic comet showers

A 26-Myr periodicity has recently been seen in the fossil record of extinction in the geological past1. At least two of these extinctions are known to be associated with the impact on the Earth of a

Cometary Impacts on the Biosphere

There is now a wealth of evidence to link impacts by comets and asteroids with catastrophic disruptions of the biosphere and mass extinctions. Such evidence includes impact craters formed close to

Spurious periods in the terrestrial impact crater record

We present a simple solution to the controversy over periodicity in the ages of terrestrial impact craters and the epochs of mass extinctions of species. The first evidence for a 28.4 mil- lion year

Evidence for a variation - but no periodicity - in the terrestrial impact cratering rate

Giant impacts by comets and asteroids have probably had an important influence on terrestrial biological evolution. There are about 180 confirmed high velocity impact craters on the Earth with ages

The Galactic Theory of Mass Extinctions: an Update

Astronomical and geological evidence is consistent with the hypothesis that mass extinctions of life on Earth are related to impacts of comets whose flux is partly modulated by the dynamics of the

Bayesian time series analysis of terrestrial impact cratering

Giant impacts by comets and asteroids have probably had an important influence on terrestrial biological evolution. We know of around 180 high-velocity impact craters on the Earth with ages up to

The evidence for and against astronomical impacts on climate change and mass extinctions: a review

It is concluded that there is little evidence for intrinsic periodicities in biodiversity, impact cratering or climate on timescales of tens to hundreds of Myr, and the numerous assumptions and uncertainties involved in the interpretation of the geological data suggest that Galactic midplane and spiral arm crossings have little impact on biological or climate variation above background level.

Are Impact Craters and Extinction Episodes Periodic? Implications for Planetary Science and Astrobiology.

Questions arise with regard to the compatibility of such periodic pulses of comet flux with the makeup of the steady-state Near Earth Object (NEO) population, the estimated long-term NEO cratering rates on the terrestrial planets, and the predicted small contribution of Oort Cloud-derived comets to the terrestrial cratering record.
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References

SHOWING 1-10 OF 11 REFERENCES

Extinction of species by periodic comet showers

A 26-Myr periodicity has recently been seen in the fossil record of extinction in the geological past1. At least two of these extinctions are known to be associated with the impact on the Earth of a

Are periodic mass extinctions driven by a distant solar companion?

Raup and Sepkoski1–3 have recently reported evidence for a 26-Myr cycle in biological mass extinctions which, if real, requires an astronomical explanation. Here we investigate a model in which this

Extraterrestrial Cause for the Cretaceous-Tertiary Extinction

A hypothesis is suggested which accounts for the extinctions and the iridium observations, and the chemical composition of the boundary clay, which is thought to come from the stratospheric dust, is markedly different from that of clay mixed with the Cretaceous and Tertiary limestones, which are chemically similar to each other.

ASTEROID AND COMET BOMBARDMENT OF THE EARTH

Two classes of solid bodies large enough to be detected by telescopes occur in orbits that overlap that of the Earth. These bodies are the Earth-crossing asteroids and comet nuclei. Although their

Iridium Anomaly Approximately Synchronous with Terminal Eocene Extinctions

The iridium anomaly and the tektites and microtektites are supportive of a major bolide impact about 34 million years ago, and other workers have deduced that the microtekkites are part of the North American strewn tektite field, which is dated at about34 million years before present.

Periodicity of extinctions in the geologic past.

  • D. RaupJ. Sepkoski
  • Geography, Environmental Science
    Proceedings of the National Academy of Sciences of the United States of America
  • 1984
The temporal distribution of the major extinctions over the past 250 million years has been investigated statistically using various forms of time series analysis and contains 12 extinction events that show a statistically significant periodicity.

Evidence for a Major Meteorite Impact on the Earth 34 Million Years Ago: Implication for Eocene Extinctions

A deep-sea core from the Caribbean contains a layer of sediment highly enriched in meteoritic iridium. This layer underlies a layer of North American microtektites dated at 34.4 million years ago and

Multiple Microtektite Horizons in Upper Eocene Marine Sediments: No Evidence for Mass Extinctions

The occurrence of microtektite horizons of several ages and the lack of evidence for faunal extinctions suggest that the effects of extraterrestrial bolide impacts may be unimportant in the biologic realm during middle Eocene to middle Oligocene time.

Rb-Sr isochron age of the Manicouagan Melt Sheet, Quebec, Canada

The Rb-Sr isotopic data for mineral separates from a rock of the Manicouagan impact melt sheet define an isochron of age T = 214 ± 5 (2σ) m.y. and an initial Sr87/sr86 ratio I = 0.70991 ± 0.00007

40Ar-39Ar ages of scandinavian impact structures: I Mien and Siljan

Abstract40Ar-39Ar ages have been obtained on samples of impact melt from the Lake Mien and Siljan hypervelocity impact structures in Sweden. Two samples of “rhyolite” from Lake Mien yield a plateau