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30 March 2011
Rusty rinds on peely rocks
Another group of interesting cobbles from the same sand and gravel pit that I described earlier in the week: Here’s the same sample, gone all animated, for your perspectivizing pleasure: What we’re seeing here is some fine-grained gray colored rock (siltstone, I guess?) that’s developed a pronounced weathering rind marked by a large amount of rust. This rusty rind is tougher than the original, unaltered rock, and it peels off, …