GSA Today
Volume 20, Number 11 (November 2010)

Cover image

About the cover:
The partly frozen, sandy shore of Lake Superior at Park Point, Minnesota, USA. Ice-cemented sand is brecciated into large blocks as it is undercut by waves in the swash zone; an analogy to conditions that occurred at least episodically along the equatorial late Cambrian shoreline of Laurentia. See “Tropical shoreline ice in the late Cambrian: Implications for Earth’s climate between the Cambrian Explosion and the Great Ordovician Biodiversification Event,” p. 4–10.

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