page_title: Cretaceous–Paleogene boundary
hierarchical_section_title: Cretaceous–Paleogene boundary
caption_attribution_description: English: Cretaceous-Paleogene clay in the Geulhemmergroeve tunnels near Geulhem, The Netherlands. Español: Arcilla cretáceo-Paleógeno en los túneles Geulhemmergroeve, cerca de Geulhem, Países Bajos.
context_page_description: The Cretaceous–Paleogene boundary, formerly known as the Cretaceous–Tertiary boundary, is a geological signature, usually a thin band of rock. K, the first letter of the German word Kreide, is the traditional abbreviation for the Cretaceous Period and Pg is the abbreviation for the Paleogene Period.
  The K–Pg boundary marks the end of the Cretaceous Period, the last period of the Mesozoic Era, and marks the beginning of the Paleogene Period, the first period of the Cenozoic Era. Its age is usually estimated at around 66 Ma, with radiometric dating yielding a more precise age of 66.043 ± 0.011 Ma.
  The K–Pg boundary is associated with the Cretaceous–Paleogene extinction event, a mass extinction which destroyed a majority of the world's Mesozoic species, including all dinosaurs except for birds.
  Strong evidence exists that the extinction coincided with a large meteorite impact at the Chicxulub crater and the generally accepted scientific theory is that this impact triggered the extinction event.
context_section_description: The Cretaceous–Paleogene (K–Pg) boundary, formerly known as the Cretaceous–Tertiary (K-T) boundary, is a geological signature, usually a thin band of rock. K, the first letter of the German word Kreide (chalk), is the traditional abbreviation for the Cretaceous Period and Pg is the abbreviation for the Paleogene Period.
  The K–Pg boundary marks the end of the Cretaceous Period, the last period of the Mesozoic Era, and marks the beginning of the Paleogene Period, the first period of the Cenozoic Era. Its age is usually estimated at around 66 Ma (million years ago), with radiometric dating yielding a more precise age of 66.043 ± 0.011 Ma.
  The K–Pg boundary is associated with the Cretaceous–Paleogene extinction event, a mass extinction which destroyed a majority of the world's Mesozoic species, including all dinosaurs except for birds.
  Strong evidence exists that the extinction coincided with a large meteorite impact at the Chicxulub crater and the generally accepted scientific theory is that this impact triggered the extinction event.
caption: Complex Cretaceous-Paleogene clay layer (gray) in the Geulhemmergroeve tunnels near Geulhem, the Netherlands. Finger is on the actual K–Pg boundary.
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