sp448.15_si_001.mpg (68.71 MB)
The origin and occurrence of subaqueous sedimentary cracks
mediaposted on 2016-11-22, 15:21 authored by Sean McMahon, Ashleigh van Smeerdijk Hood, Duncan McIlroy
Video of a micro-CT scan through a hand-sample showing molar tooth cracks from the Monteville Formation, South Africa (c. 2.6 Ga). These ptygmatic to linear cracks occur in swarms in finer carbonate-clay beds of the formation and are filled with very finely crystalline calcite spar. The field of view is about 5 cm across.