Geologic setting and geomorphic history of the La Botica area, south-central Colorado

La Botica is positioned on a topographic bench sharply inset into the gentle eastern slope of the high San Juan Mountains and perched ~70-80 meters above La Jara Creek (fig. 1), a tributary to the Rio Grande. Quaternary surface processes have modified the Tertiary bedrock deposits that underlie La Botica to shape the physical environment. Bedrock deposits consist of Oligocene to Pliocene volcanic and sedimentary deposits related to the Rio Grande rift and the San Juan volcanic locus of the Southern Rocky Mountains volcanic field. Bedrock deposits are mildly deformed by normal faulting and eastward tilting related to the onset of extensional deformation in the Oligocene and formation of the San Luis Basin. Bedrock incision by La Jara Creek is connected with evolution of the Rio Grande, and precursors, since middle to late Pleistocene regional alpine glacial cycles over the last 500 k.y.