Cross-bedded sandstone (fossilized sand dunes) near Kanab, Utah. Careful study of cross-bedding can be used to tell which way was up. |
Two sedimentary structures for the price of one; mudcracks and raindrop impressions, Arches National Park, Utah. The curl direction of mudcracks and indentation of raindrop imprints also give paleo-up. |
More modern mudcracks, in Death Valley. |
Ripple marks along the shore of the island of Paros, Greece. These form in modern sands by sloshing of water in the bay. These are about 5 cm from crest to crest; view is looking straight down through the water. |
Two more sedimentary structures for the price of one; ripple marks and salt casts. Cubic impressions in the rippled layer are casts of evaporitic salt (halite) that grew in the sandstone when it dried out. Northern Arizona. |