Inverted topography on the Colorado Plateau | Black Mesa is a Pleistocene-age basaltic lava flow outlier of the Springerville volcanic field of east central Arizona. At the time of effusion, the lava flow was captured by a NNW-trending drainage, accounting for its nearly 11-mile length and narrow width (roughly 1,500 to 4,000 feet). The lava flow is approximately 350 feet thick. The original stream gradient was in the neighborhood of 0.0136. Since the lava flow was emplaced over 1 million years ago, the surrounding Triassic shales and sandstones have been beveled. As a result, the resistant lava flow now stands 100s of feet above the surrounding plain, a classic example of inverted topography. Image courtesy of Google Earth
Photographer: Mike Conway
Photo Date: 2017