Earth & Environmental Science Journalism:

Science Research Project

A re-evaluation of tektites associated with the proposed Mahuika impact.

Mohana Kumar


A 1km bolide impact has been proposed to have struck 500 years ago southwest of New Zealand’s South Island, in the shallow waters off the continental shelf (48.3 S, 166.4 E.).  The main evidence supporting this theory was the presence of tektites found in seven out of seventeen dredge hauls around the proposed crater.  However, closer inspection of these tektites revealed they are not glass, but microcrystalline.  SEM analysis showed that these nodules are authigenic clays that form rounded casts inside hollow foraminifera.  Rough EDX analysis shows that this clay is likely to be a glauconitic compound.  However, one strong tektite candidate was found, as were two mineral grains that possibly show planar deformation features associated with shock metamorphism.  Also impact-derived SiC may have been found.  The lack of a tektite field necessitates further research to be conducted to establish the proposed Mahuika impact as an actual event.


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Last updated: 18 January 2006, MKT.