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. 2020 Mar 25;20(4):475–499. doi: 10.1089/ast.2019.2044

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© Steven W. Ruff et al., 2020; Published by Mary Ann Liebert, Inc.

This Open Access article is distributed under the terms of the Creative Commons Attribution Noncommercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.

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FIG. 19. — Cobbles and boulders of granitic regolith cemented by opaline silica near Opal Mound, Utah. Rectangle represents the inset view showing layer of sinter in sharp contact with the substrate. Blue rock hammer handle is ∼20 cm long.