#sedimentology

by Bernard Dupont

These ripples are preserved in this sandstone rock and are now lining a dry creek bed in Australian outback. But, it was around 2 billion years ago when motion of water formed these sand ripples on the bottom of a shallow sea. Note that orientation of ripples is different between sedimentary layers which indicates changes to water current direction.

Here are some ripple marks from a beach in the Northwest Scottish Highlands! There’s a chance that these ripple marks will be preserved like this and become sedimentary structures that we can see as cross-bedding in an outcrop someday!

Some recent microscope photos! First two are sand and the eyeball lookin one is fossil sponge :)