Tecopa Mud Hills
Along the boundaries the vegetation is dry and sparse. In the hills, nothing grows in the crusted ash.
During the late Pliocene and early Pleistocene, a climate that was appreciably wetter than today' s sustained a moderately deep lake in the Tecopa basin. Deposits associated with Lake Tecopa consist of lacustrine mudstone, conglomerate, volcanic ash, and shoreline accumulations of tufa. Age control within the lake deposits is provided by air-fall tephra that are correlated with two ash falls from the Yellowstone caldera, the Lava Creek (0.62 Ma) and Huckleberry Ridge (2.02 Ma) Tuffs, and one from the Long Valley caldera, the Bishop Tuff (0.73 Ma).
Ma. = million years ago
Source = LATE TERTIARY AND QUATERNARY GEOLOGY OF THE TECOPA BASIN, SOUTHEASTERN CALIFORNIA
By John W. Hillhouse
