Comet showers as a cause of mass extinctions

  title={Comet showers as a cause of mass extinctions},
  author={Piet Hut and Walter Alvarez and William P. Elder and Thor A. Hansen and Erle G. Kauffman and Gerta Keller and Eugene Merle Shoemaker and Paul R. Weissman},
If at least some mass extinctions are caused by impacts, why do they extend over intervals of one to three million years and have a partly stepwise character? The solution may be provided by multiple cometary impacts. Astronomical, geological and palaeontological evidence is consistent with a causal connection between comet showers, clusters of impact events and stepwise mass extinctions, but it is too early to tell how pervasive this relationship may be. 
End-Cretaceous Mass Extinction Event: Argument for Terrestrial Causation
By analysis of physical and chemical evidence from the stratigraphic record it is shown that a modified extraterrestrial model in which stepwise extinctions resulted from encounter with a comet shower is less plausible than one intrinsic to the earth, involving significant disturbance in the mantle. Expand
The reasons for the mass extinctions, which occur from time to time in Earth's history -as, e.g., the dinosaur extinction at the Cretaceous/Tertiary boundary 65 myr ago - are still not satisfactorilyExpand
Galactic Triggering of Periodic Comet Showers and Mass Extinctions on Earth
Geological and astronomical studies can be synthesized to provide a hypothesis connecting the history of life on Earth with the dynamics of the Galaxy. Impacts of comets and asteroids on the EarthExpand
A multi-causal model of mass extinctions: Increase in trace metals in the oceans
Mass extinctions of life may be the net result of multiple, related causes. The correlation among mass extinctions, large-body impacts, ocean anoxic events, and flood-basalt volcanism suggests someExpand
The case for extraterrestrial causes of extinction.
  • D. Raup
  • Geology, Medicine
  • Philosophical transactions of the Royal Society of London. Series B, Biological sciences
  • 1989
The challenge for future research is to develop a new calculus for treating biostratigraphic data so that fossils can provide more accurate assessments of the timing of extinctions. Expand
Impacts, volcanism and mass extinction: random coincidence or cause and effect?
Large impacts are credited with the most devastating mass extinctions in Earth's history and the Cretaceous – Tertiary (K/T) boundary impact is the strongest and sole direct support for this view. AExpand
Death Stars, Ecology, and Mass Extinctions
Evidence for extrinsic influences on the biosphere will certainly aid in comprehending the nature of biohistorical events, such as mass extinctions, and may well be responsible for... Expand
Mass Extinctions: Astronomical Influence or Earthly Causes?
Periodic impacts of asteroids or comets may cause mass mortality of the Earth's biota, but the evidence is far from conclusive.
Stepwise mass extinctions: the case for the Late Cenomanian event
The various extinctions of marine taxa in the Late Cenomanian can be shown as conforming to the ‘step-wise extinction’ model. The order of such extinctions is, however, compatible with the presenceExpand
A Unified Theory of Impact Crises and Mass Extinctions: Quantitative Tests
Several quantitative tests of a general hypothesis linking impacts of large asteroids and comets with mass extinctions of life are possible based on astronomical data, impact dynamics, and geological information predict that impacts of objects ≥ 5 km in diameter could be sufficient to explain the record of 25 extinction pulses. Expand


Impact Theory of Mass Extinctions and the Invertebrate Fossil Record
The paleontological record bears witness to terminal-Cretaceous extinctions on two time scales: a slow decline unrelated to the impact and a sharp truncation synchronous with and probably caused by the impact. Expand
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 aExpand
Evidence from crater ages for periodic impacts on the Earth
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 RaupExpand
Periodicity of extinctions in the geologic past.
  • D. Raup, J. Sepkoski
  • Biology, Medicine
  • 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. Expand
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 andExpand
Toward a theory of impact crises
In a certain sense, the impact explanation for the mass extinction at the end of the Cretaceous had its origin in Lamont Hall. A couple of years after I came to Lamont in 1971, I started working withExpand
Sanidine spherules at the Cretaceous–Tertiary boundary indicate a large impact event
The hypothesis that a catastrophic impact of an extraterrestrial body caused the terminal Cretaceous mass extinctions of dinosaurs, planktonic foraminfera and other species is now accepted asExpand
Periodic extinction of families and genera.
Time-series analysis of eight major episodes of biological extinction of marine families over the past 250 million years strongly suggests a 26-million-year periodicity, robust even when adjusted for simultaneous testing of many trial periods. Expand
Terminal Cretaceous Environmental Events
The geologic record of terminal Cretaceous environmental events indicates that iridium and other associated elements were not deposited instantaneously but during a time interval spanning some 10,000 to 100,000 years, which favors a mantle rather than meteoritic origin for these elements. Expand
Biological extinction in earth history.
A drop in sea level and climatic change are most frequently invoked to explain mass extinctions, but new theories of collisions with extraterrestrial bodies are gaining favor. Expand