A record of the micrometeorite flux during an enigmatic extraterrestrial 3He anomaly in the Turonian (Late Cretaceous)
We reconstructed a record of the micrometeorite flux in the Late Cretaceous using the distribution of extraterrestrial spinel grains across an ~2 m.y. interval of elevated 3He in the Turonian Stage (ca. 92–90 Ma). From ~30 m of the limestone succession in the Bottaccione section, Italy, a total of 979 kg of rock from levels below and within the 3He excursion yielded 603 spinel grains (32–355 µm si
