author={Adrian L. Melott and Richard K. Bambach},
  journal={The Astrophysical Journal},
A major revision of the geological timescale was published in 2012. We re-examine our past finding of a 27 Myr periodicity in marine extinction rates by re-assigning dates to the extinction data used previously. We find that the spectral power in this period is somewhat increased, and persists at a narrow bandwidth, which supports our previous contention that the Nemesis hypothesis is untenable as an explanation for the periodicity that was first noted by Raup & Sepkoski in the 1980s. We… 

Mass extinctions over the last 500 myr: an astronomical cause?

A Fourier analysis of the magnitudes and timing of the Phanerozoic mass extinctions (MEs) demonstrates that many of the periodicities claimed in other analyses are not statistically significant.

Analysis of periodicity of extinction using the 2012 geological timescale

Analysis of two independent data sets with increased taxonomic resolution using the revised 2012 timescale reveals that an extinction periodicity first detected by Raup and Sepkoski (1984) for only the post-Paleozoic actually runs through the entire Phanerozoic.

Evidence for periodicities in the extinction record? Response to Melott & Bambach [arXiv:1307.1884]

The bottom line is that although one can get a periodic model at some period to fit the extinction data, there are other models which explain the data better.

Periodic mass extinctions and the Planet X model reconsidered

The 27 Myr periodicity in the fossil extinction record has been confirmed in modern data bases dating back 500 Myr, which is twice the time interval of the original analysis from thirty years ago.

Does the planetary dynamo go cycling on? Re-examining the evidence for cycles in magnetic reversal rate

Abstract The record of reversals of the geomagnetic field has played an integral role in the development of plate tectonic theory. Statistical analyses of the reversal record are aimed at detailing

Giant comets and mass extinctions of life

I find evidence for clustering in age of well-dated impact craters over the last 500 Myr. At least nine impact episodes are identified, with durations whose upper limits are set by the dating

Periodicity in extinction rates

Publisher's copyright statement: This is the accepted version of the following article: Erlykin, A. D., Harper, D. A. T., Sloan, T., Wolfendale, A. W. (2017), Periodicity in extinction rates.

Comment on 'Investigations into the impact of astronomical phenomena on the terrestrial biosphere and climate' (arXiv:1505.07856 [astro-ph.EP]) by Fabo Feng

This work by Feng and papers which published its conclusions do not cite nor do they deal with objections by the author published in 2013-2014, which render irrelevant most of the work presented by Feng.

Disc dark matter in the Galaxy and potential cycles of extraterrestrial impacts, mass extinctions and geological events

A cycle in the range of 26–30Myr has been reported in mass extinctions, and terrestrial impact cratering may exhibit a similar cycle of 31 ± 5Myr. These cycles have been attributed to the Sun’s



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.

Nemesis reconsidered: Nemesis reconsidered

This work examines the evidence for the previously proposed periodicity of a companion object orbiting the Sun, using two modern, greatly improved paleontological datasets of fossil biodiversity, and finds that there is a narrow peak at 27 My in the cross-spectrum of extinction intensity time series between these independent datasets.

Dynamics of origination and extinction in the marine fossil record

  • J. Alroy
  • Environmental Science, Geography
    Proceedings of the National Academy of Sciences
  • 2008
The discipline-wide effort to database the fossil record at the occurrence level has made it possible to estimate marine invertebrate extinction and origination rates with much greater accuracy. The

A ubiquitous ~62-Myr periodic fluctuation superimposed on general trends in fossil biodiversity. I. Documentation

Joint time-series analysis of various reductions of the Sepkoski Data, Paleobiology Database, and Fossil Record 2 indicate the same periodicity in biodiversity of marine animals at 62 Myr, but it is found that the signal strength decreases with time because of the accumulation of apparently “resistant” long-lived genera.

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

Considering the Case for Biodiversity Cycles: Re-Examining the Evidence for Periodicity in the Fossil Record

The signal is robust against variations in methods of analysis, and is based on fluctuations in the Paleozoic and a substantial part of the Mesozoic.

A ubiquitous ∼62-Myr periodic fluctuation superimposed on general trends in fossil biodiversity. II. Evolutionary dynamics associated with periodic fluctuation in marine diversity

The presence of a periodic pattern in evolutionary dynamics of the more vulnerable “short-lived” component of the marine fauna demonstrates that a long-term periodic fluctuation in environmental conditions capable of affecting evolution in the marine realm characterizes the authors' planet's history.

An ∼60-Million-Year Periodicity Is Common to Marine 87Sr/86Sr, Fossil Biodiversity, and Large-Scale Sedimentation: What Does the Periodicity Reflect?

It is found that the marine 87Sr/86Sr record shows a significant periodicity that reflects the operation of a periodic “pulse of the earth” in large-scale earth processes, which may be linked to mantle or plate-tectonic events, possibly uplift, which affects the earth's climate and oceans and, thus, the geochemistry, sedimentation and biodiversity of the marine realm.


It is difficult to give convincing positive conclusions of such a connection between solar motion and biodiversity variations on the Earth using current data, and various versions of the orbital model are not favored beyond simpler reference models.

Time Scales of Critical Events Around the Cretaceous-Paleogene Boundary

Radiometric dating establishes the mass extinction that killed the dinosaurs as synchronous with a large asteroid impact between the Cretaceous-Paleogene boundary and associated mass extinctions with the Chicxulub bolide impact to within 32,000 years.