Pinnacles National Park
Barren outcrops of rock (in this case, the volcanic rock, rhyolite tuff) shows that physical erosion on the surface is proceeding at a faster rate than the chemical breakdown of rock (which typically occurs underground and results in the formation of soil). This pattern is common in semi-arid regions where long periods of drying occur between episodes of heavy precipitation, either seasonal or through periods of drought. This is typical of higher elevations in regions with Mediterranean climates like the Coast Ranges of California (Scarciglia and others, 2007). In the past, during extended cooler and wetter periods, soil with a deep weathering profile may have covered areas like this.
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Last modified: 10/21/2010