Geological record and reconstruction of the late Pliocene impact of the Eltanin asteroid in the Southern Ocean

Abstract

In 1995, an expedition on board the research vessel FS Polarstern explored the impact site of the Eltanin asteroid in the Southern Ocean, the only known asteroid impact into a deep ocean basin. Analyses of the geological record of the impact region place the event in the late Pliocene (approximately 2.15 Myr) and constrain the size of the asteroid to be >1 km. The explosive force inferred for this event places it at the threshold of impacts believed to have global consequences, and its study should therefore provide a baseline for the reconstruction and modelling of similar events, which are common on geological timescales.

Microtektites on Mars: Volume and Texture of Distal Impact Ejecta Deposits

“…However, on Earth, the thick atmosphere and high gravity conspire to make impacts capable of dispersing ejecta globally fairly rare, and the ice sheets themselves are young, so there are no known impact ejecta layers in the ice. It is, however, believed that marine diatoms found on the ice-free Transantarctic Mountains may have been emplaced there as ballistic ejecta from the >1-km-diameter Eltanin asteroid impact in the Southern Ocean 2.15 Myr ago (Gersonde et al 1997, Smit, 1997.…”

Nonequilibrium Diversity Dynamics of the Lesser Antillean Avifauna

“…Potential causes would include a tsunami produced by a marine landslide (22) or deepwater bolide impact (23), which rarely leave superficial geological evidence (24). Hurricanes and volcanic eruptions are probably too localized to cause widespread extinction (25,26), but loss of habitat following abrupt climate change might have a regional impact.…”

Data Report: A Search for Deposits of the late Pliocene Impact of the Eltanin Asteroid in Rise Sediments from the Antarctic Peninsula, Site 1096

“…These deposits provide a natural laboratory for studying processes related to the formation and preservation of Ir-rich meteoritic ejecta. The current estimate of the size of the projectile (Gersonde et al, 1997), from 1 to 4 k m in diameter, is well within the range of asteroid sizes proposed to have global consequences (Chapman and Morrison, 1994). This impact must have generated large tsunamis throughout much of the Pacific basin and around much of the Southern Ocean.…”

“…The exact point of impact is unknown, but it is believed to have occurred in the Bellingshausen Sea in a region -1000 km west of Cape Horn (5S0S, 9OOW). Details of the study of this impact are found in a series of five papers (Kyte et al, 1981(Kyte et al, , 1988Kyte and Brownlee, 1985;Margolis et al, 1991;Gersonde et al, 1997). The impact ejecta deposits…”