Burckle Crater

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Burckle crater
Burckle crater is located in Indian Ocean
Burckle crater
Burckle crater
Location of Burckle Crater in the Indian Ocean
Impact crater/structure
ConfidenceHypothesized, contested
Diameter~29 km (18 mi)
Depth3,800 m (12,500 ft)
Age~5000 years (Holocene)
ExposedNo
DrilledNo
Bolide typeUnknown, possibly remains of a comet
Location
Coordinates30°51′54″S 61°21′54″E / 30.865°S 61.365°E / -30.865; 61.365Coordinates: 30°51′54″S 61°21′54″E / 30.865°S 61.365°E / -30.865; 61.365

Burckle crater is an undersea feature that is hypothesized to be an impact crater by the Holocene Impact Working Group. They considered that it likely was formed by a very large-scale and relatively recent (c. 3000–2800 BCE) meteorite impact event, possibly resulting from a comet. It is estimated to be about 29 kilometres (18 mi) in diameter,[1] about 25 times wider than Meteor Crater in Arizona.

Description[edit]

The feature is located east of Madagascar and west of Western Australia in the southern Indian ocean, adjacent to the SW Indian Ocean Ridge.[2] Its position was determined in 2006 by the Holocene Impact Working Group using prehistoric chevron dune formations in Australia and Madagascar. Based on the hypothesis these dunes were formed by a megatsunami resulting from an impact, the researchers were able to triangulate the location of Burckle crater. The hypothesis that these chevron dunes were caused by a megatsunami has been challenged by geologists Jody Bourgeois and R. Weiss in 2009. Using a computer model to simulate a tsunami, they argue that the structures are more consistent with aeolian processes.[3] The tsunami origin of these chevrons is also disputed by other Earth scientists.[4]

Burckle crater is located at 30°51′54″S 61°21′54″E / 30.865°S 61.365°E / -30.865; 61.365 in the Indian Ocean and is 3,800 metres (12,500 ft) below the surface.

Formation[edit]

Burckle crater has not yet been dated by radiometric analysis of its sediments. The Holocene Impact Working Group researchers think that it formed about 5,000 years ago (c. 2800–3000 BCE), during the Holocene epoch. They consider the possibility that (the remains of) a comet impacted the ocean floor, and that subsequent megatsunamis created the dune formations which allowed the crater to be pin-pointed.

Unusual calcite (CaCO3) crystals, translucent carbon spherules, fragments of basaltic glass and native metals (native iron and nickel) are reported near the crater and associated with impact ejecta or hot water precipitates. Seawater at the depth of the crater is undersaturated with respect to calcite and rapid burial would have been needed to preserve those crystals.[2]

See also[edit]

References[edit]

  1. ^ Abbott et al., 2006
  2. ^ a b Abbott et al., 2009
  3. ^ Bourgeois & Weiss, 2009
  4. ^ Pinter & Ishman, 2008, p.37

Bibliography[edit]

External links[edit]