Knowra Impact crater Impact crater An impact crater is a roughly circular depression formed when a solid body strikes a planetary surface at high speed. Its shape and surrounding deposits record the collision and the target surface.
Impact cratering process : The sequence of shock compression, excavation, crater modification, and ejecta deposition caused by a hypervelocity impact. It explains how a brief collision produces a large, structured depression.
Barringer Crater : A young impact crater in Arizona, also known as Meteor Crater. Its preserved bowl and surrounding debris made it a key case for recognizing impact craters on Earth.
Crater counting : A method for estimating the relative age of a planetary surface from its impact-crater density. Crater populations provide surface-age estimates where direct dating is unavailable.
Volcanic crater : A depression formed by volcanic activity, such as collapse, explosion, or excavation around a vent. Its volcanic origin can resemble an impact crater in outline but produces different structures and deposits.
Shock metamorphism : Mineral and rock changes produced by the intense pressure of shock waves. Shock-altered minerals preserve evidence of the pressures generated beneath an impact.
Chicxulub crater : A buried impact structure beneath Mexico's Yucatán Peninsula, associated with the end-Cretaceous mass extinction. Its discovery linked a large crater to a globally consequential impact.
Impact event : A collision in which an astronomical body strikes a planet, moon, or other celestial object. A crater is the lasting geological record of an impact event.
Caldera : A large volcanic depression formed when a magma chamber empties and the overlying ground collapses. Calderas can be circular, but their collapse structures distinguish them from impact excavations.
Ejecta : Material expelled from a crater or vent and deposited beyond its opening. Ejected rock forms deposits around the crater and can reveal impact direction and scale.
Vredefort crater : A deeply eroded impact structure in South Africa and the largest confirmed impact structure on Earth. Its immense, altered structure illustrates how erosion can obscure an ancient crater.
Show all 21