Volcanology
Sierra Blanca is a massive complex of volcanic rocks including pyroclastic materials, lava flows, and intrusions. An ancient and heavily eroded volcanic pile, it is the largest mid-Tertiary volcanic complex east of the Rio Grande with an estimated volume of erupted products of 185 cubic miles (770 km3). Eruptions began about 38 million years ago, and extended over a twelve-million-year period. Most of the eruptions produced volumnious lava flows and breccias, with numerous intrusive dikes emplaced throughout the complex. The final activity produced the intrusions which form the present-day Sierra Blanca Peak. Following the volcanic period the range's topography was further modified by Pleistocene glaciation, block faulting and erosion.
Read more about this topic: Sierra Blanca (New Mexico)