GSA Today
Volume 20, Number 2 (February 2010)

About the cover:
Hard, virtually unweathered bedrock in the Sierra Nevada, California, USA, supports a sparse ecosystem in which plants only grow in joint fractures (photo credit: Malcolm M. Clark). Porosity produced by weathering converts such biologically inert rock into regolith that holds water and supports more productive ecosystems. See “Rock to regolith conversion: Producing hospitable substrates for terrestrial ecosystems,” by R.C. Graham et al., p. 4–9.

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