An asteroid breakup 160 Myr ago as the probable source of the K/T impactor

  title={An asteroid breakup 160 Myr ago as the probable source of the K/T impactor},
  author={William F. Bottke and David Vokrouhlick{\'y} and David Nesvorn{\'y}},
The terrestrial and lunar cratering rate is often assumed to have been nearly constant over the past 3 Gyr. Different lines of evidence, however, suggest that the impact flux from kilometre-sized bodies increased by at least a factor of two over the long-term average during the past ∼100 Myr. Here we argue that this apparent surge was triggered by the catastrophic disruption of the parent body of the asteroid Baptistina, which we infer was a ∼170-km-diameter body (carbonaceous-chondrite-like… 

Asteroid break-ups and meteorite delivery to Earth the past 500 million years

It is argued that meteorites and small asteroids impacting Earth mainly sample a very small region of orbital space in the asteroid belt, and the flux of extraterrestrial material would vary in accordance with the timing of such asteroid family-forming events.

Forming the Flora Family: Implications for the Near-Earth Asteroid Population and Large Terrestrial Planet Impactors

Formed from a catastrophic collision of a parent body larger than 150 km in diameter, the Flora family is located in the innermost part of the main belt near the secular resonance. Objects in this

Two large meteorite impacts at the Cretaceous-Paleogene boundary

The end-Cretaceous mass extinction has been attributed by most to a single asteroid impact at Chicxulub on the Yucatan Peninsula, Mexico. The discovery of a second smaller crater with a similar age

The breakup of a long-period comet is not a likely match to the Chicxulub impactor

Since the discovery of Ir in the clay layer at the K-Pg boundary 1 , scientists have sought to constrain the origin of the extraterrestrial impactor that triggered the end-Cretaceous mass extinction

Composition of 298 Baptistina: Implications for the K/T impactor link

Abstract— Bottke et al. (2007) suggested that the breakup of the Baptistina asteroid family (BAF) 160+30/‐20 Myr ago produced an “asteroid shower” that increased by a factor of 2–3 the impact flux of



Discovery of a 25-cm asteroid clast in the giant Morokweng impact crater, South Africa

The discovery of a large (25-cm), unaltered, fossil meteorite and several smaller fragments within the impact melt of the giant Morokweng crater, South Africa, suggests that the MorokWeng asteroid incorporated part of the LL chondrite parent body not represented by objects at present reaching the Earth.

Iron meteorites as remnants of planetesimals formed in the terrestrial planet region

It is shown that the iron-meteorite parent bodies most probably formed in the terrestrial planet region, and it is predicted that some asteroids are main-belt interlopers and a select few may even be remnants of the long-lost precursor material that formed the Earth.

A meteorite from the Cretaceous/Tertiary boundary

Cretaceous/Tertiary boundary sediments are now widely recognized to contain the record of a large asteroid or comet impact event, probably at the site of the Chicxulub crater on the Yucatan

Comet or Asteroid Shower in the Late Eocene?

New platinum-group element analyses indicate that Popigai was formed by the impact of an L-chondrite meteorite, suggesting that the higher delivery rate of extraterrestrial matter, dust, and large objects was caused by a major collision in the asteroid belt.

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.

40Ar/39Ar dating of Apollo 12 impact spherules

We have used the 40Ar/39Ar isochron technique to determine ages of 81 lunar spherules from Apollo 12 soil sample 12023. Most spherules are created in meteoroid impacts, and their ages correspond to