The results of the Cambrian explosion are well documented in the fossil record
, but its cause -- why and when it happened, and perhaps why nothing similar has happened since -- has been a mystery. Now a recent paper
in Nature (abstract
) suggests that the answer may lie in a second geological curiosity -- a dramatic boundary, known as the Great Unconformity
, between ancient igneous and metamorphic rocks and younger sediments.
posted by Long Way To Go
on Jun 23, 2013 -