In volcanology, ejecta consists of particles that came out of a volcanic vent, traveled though the air or under water, and fell back on the ground surface or on the ocean floor. Ejecta can consist of
juvenile particles - (fragmented magma and free crystals)
cognate or accessory particles - older volcanic rocks from the same volcano
accidental particles - derived from the volcanic basement.
In planetary geology, ejecta can also refer to the debris that is ejected during the formation of an impact crater.
Much of this is banked into the familiar circular wall, whilst most of the rest of the ejecta - the material thrown out by the impact - is generally deposited as bright rays radiating from the impact site.
In large impacts, some of the ejecta can be thrown out at more than the Moon's escape velocity.
Fragments of this have eventually reached the Earth, to fall as meteorites.
The diamictite is a direct ejecta deposit, itself 14-m thick, comprised of debris ranging from clay-size to 8-m diameter boulders.
Bedding in Belizan ejecta diamictite is particularly interesting because it suggests that different parts of the ejecta flow were moving at slightly different speeds or took slightly different flow paths.
In the foothills of the Maya Mountains, and in the Cayo District of central Belize near Belmopan, the capital of Belize, a sedimentary layer approximately 30 m thick comprises the Cretaceous-Tertiary (KT) boundary.
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