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Figure F60. Representative core photographs of veins. A. Veins within a rheologically hard lava flow of aphyric basalt in Unit IV (interval 330-U1374A-5R-3A, 86.5–97.5 cm). A thicker vein runs nearly vertical, with several smaller subhorizontal offshoots or conjugate veins. The subhorizontal magmatic foliation of this lava (Table T10) asserts some control on conjugate vein orientation. B. Fragment of aphyric lava within Unit X (interval 17R-2A, 21.5–35 cm). This piece has lobate margins, a quenched rim, and a vesicular core, suggesting it may be a small pillow. Several irregular veins radiate away from the vesicular core. Note how the veins are restricted to the rheologically harder lava and do not extend into the surrounding matrix, where fluid flow would have been easier and more diffuse. C. One of the rare examples of a vein crosscutting the breccia matrix (interval 62R-2A, 92.5–109.5 cm). This steeply dipping vein is located close to one of the sheet intrusions, which may have enhanced fluid flow in the vicinity.

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