An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 3 Search : Cretaceous
Cretaceous
  گچاسا   
Gacâsâ

Fr.: Crétacé   

A period of → geologic time which began at the end of the → Jurassic period approximately 145 million years ago and extended to approximately 65 million years ago.

From L. cretaceus, from cret(a) "chalk, clay," + → -aceous, because the geological remains of this period contain heightened chalk deposits.

Gacâsâ, from gac "chalk," Mid.Pers. gac + -âsâ, → -aceous.

Cretaceous-Paleogene extinction event
  رویداد ِ خاموشی ِ گچاسا-پارینزاد   
ruydâd-e xâmuši-ye Gacâsâ-Pârinzâd

Fr.: extinction Crétacé-Tertiaire   

The → mass extinction event that destroyed the dinosaurs and a majority of other species on Earth approximately 65 million years ago. This event is believed to have been the impact of a 10 km-size → asteroid or → comet nucleus and its aftereffects, including a severe → impact winter. Same as the → Cretaceous-Tertiary event.

Cretaceous; → Paleogene; → extinction; → event.

Cretaceous-Tertiary event
  رویداد ِ K-T   
ruydâd-e K-T (#)

Fr.: événement K-T   

See → Cretaceous-Paleogene extinction event.

K, representing the "→ Cretaceous period," and T the "→ Tertiary;" → event.