Accretionary Lapilli

Pellets that form by accretionAccumulation of smaller objects into progressively larger bodies in the solar nebula leading to the eventual formation of asteroids, planetesimals and planets. The earliest accretion of the smallest particles was due to Van der Waals and electromagnetic forces. Further accretion continued by relatively low-velocity collisions of smaller bodies in the Click on Term to Read More of fine ash around condensing water droplets or solid particles; particularly common in steam-rich volcanicIgneous rock that forms from cooling magma on the surface of a planet or asteroid. eruptive columns, but also occurring in the turbulent explosion plume rising above an expanding excavation cavity in an impact cratering event. Accretionary lapilli exhibiting concentric internal structure have been found in deposits at the Ries impact structure and in ejectaFractured and/or molten rocky debris thrown out of a crater during a meteorite impact event, or, alternatively, material, including ash, lapilli, and bombs, erupted from a volcano. Click on Term to Read More deposits from the Chicxulub craterLarge (150-180 km wide and 20 km deep), partially submerged, multi-ringed impact crater straddling the northwest coastline of the Yucatan Peninsula in Mexico. It is named after a village located near its center (21° 20' N, 89° 30' W). The Chixculub Crater is believed to have formed 66 million years Click on Term to Read More in Mexico.

The meteoriteWork in progress. A solid natural object reaching a planet’s surface from interplanetary space. Solid portion of a meteoroid that survives its fall to Earth, or some other body. Meteorites are classified as stony meteorites, iron meteorites, and stony-iron meteorites. These groups are further divided according to their mineralogy and Click on Term to Read More NWA 7034 and its pairings include what some scientists are calling accretionary lapilli and others call “blueberries.”