Boulder, Colo., USA – Geology articles posted online ahead of print this month survey topography, minerals, faults and tectonics, alluvium, modeling, snowball Earth, fossils and extinction, and pyrite-filled worm burrows. One notable study provides a new eruption date for the Salton Buttes (Calif., USA) of 30,000 years later than that determined by earlier studies, coinciding with the appearance of the earliest known obsidian tools there.