Grain orientation and electron microprobe analyses of selected Phanerozoic trace fossil margins, with a possible Proterozoic example

Grains at the margins of Ordovician and Silurian Skolithos were oriented significantly parallel to the trace in vertical section, and tangential to the margin in horizontal section. Control analyses showed no similar orientations developed away from the traces. Microprobe analyses of the same traces showed anomalous concentrations of cations at trace margins. Similar analyses of impregnated Holocene burrows suggest that these cation …