A perspective on the evidence for periodic cometary impacts on Earth

Details A perspective on the evidence for periodic cometary impacts on Earth A perspective on the evidence for periodic cometary impacts on Earth

Dec 1985

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1985e%26psl..76....1g&link_type=abstract

Earth and Planetary Science Letters, Volume 76, Issue 1-2, p. 1-9.

Computer Science

33

Scientific paper

Recent suggestions of periodic cometary showers coincident with mass extinctions have prompted a review of the terrestrial cratering record. From the point of view of completeness of search and crater retention, the record used to argue for statistical periodicities is incomplete and may not be representative. Estimates of crater ages are of variable accuracy and precision and, in some cases, different dating methods yield discordant results. It is possible to define through time-series analysis a number of periodicities of different magnitude ( ~ 29 m.y., ~ 21 m.y., ~ 18.5 m.y., ~ 13.5 m.y.) and phase, depending on which craters are considered the most representative sample of the record. Arguing against periodic cometary showers is the observation that estimates of the average cratering rate in recent time and observations on Apollo bodies are equivalent. In addition, siderophile element data from impact melt rocks suggest a variely of projectile types were responsible for relatively large terrestrial craters. Given these observations, it is concluded that statements regarding periodic cometary showers are not categorical and require evidence beyond arguments based on time-series analyses of an incomplete cratering record.

Affiliated with

Also associated with

No associations

Rating

A perspective on the evidence for periodic cometary impacts on Earth does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with A perspective on the evidence for periodic cometary impacts on Earth, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A perspective on the evidence for periodic cometary impacts on Earth will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1161302