high res (0.8 M) low res (106 K)

ISS017-E-009598 (18 June 2008) --- The Sentinel Volcanic Field in Arizona is featured in this image photographed by an Expedition 17 crewmember on the International Space Station. This detailed view depicts a portion of the Gila River channel (center) between the Sentinel Volcanic Field and Oatman Mountain in south-central Arizona. The northernmost boundary of the Sentinel field is visible in the image, recognizable by the irregular flow fronts, or leading edge, of thin basalt lava flows erupted from low volcanic cones approximately 3.3--1.3 million years ago, according to scientists. Coloration of the lava flow tops ranges from dark brown exposed rock to a tan, carbonate-rich soil cover.

Active agricultural fields along the Gila River are a rich green set against the surrounding desert. In contrast to the gentle topography of the Sentinel Volcanic Field, Oatman Mountain (upper left) rises from the Gila River channel to an elevation of approximately 560 meters. While Oatman Mountain is located close to the Sentinel field, it represents an earlier phase of volcanic activity in the area. Volcanic rocks comprising Oatman Mountain were more viscous, leading to shorter, stronger flows that are weathered into stream channels and scarps on the mountain slopes. The mountain is a popular hang gliding destination due to abundant thermal currents rising from the surrounding desert floor and lava surfaces.

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