Volcanic stratigraphy of the Paradise Mountain Caldera Complex, Davis Mountains, Texas, USA.
Author ORCID Identifier
Department
Physics, Geosciences, and Astronomy
Document Type
Book Chapter
Publication Date
2025
Abstract
The Davis Mountains are the largest contiguous remnant of the mid-Tertiary Trans-Pecos Magmatic Province, one of the largest alkalic provinces in North America. The Paradise Mountain Caldera produced two major ignimbrite and lava complexes at ca. 36.2 and 35.9 Ma. The older unit (Fort Davis Tuff) is composed of rheomorphic tuff and overlying chemically similar lavas of Blue Mountain Rhyolite that appear to cover the source. The younger unit (Wild Cherry Tuff) forms thick intra-caldera deposits and an extensive outflow. We visit intra-caldera Wild Cherry Tuff intruded by silicic intrusions which that are locally intensively silicified and kaolinized. Near the caldera, both ignimbrites are separated by lava of the Mount Locke Formation.
New mapping at McDonald Observatory and Pine Peak recognizes new stratigraphic units and revises existing units. Mount Locke is the type locality of the ca. 36 Ma Mount Locke Formation, a highly porphyritic metaluminous trachyte. The type locality inadvertently included the entirety of the Wild Cherry Tuff and Casket Mountain Formation trachyte. Both are properly recognized, and the Mount Locke is restricted to 93 m of coarse trachyte porphyry. Previously mapped Wild Cherry on Mount Locke is reassigned to Casket Mountain and on Mount Fowlkes to Goat Canyon Formation. A distinctive highly porphyritic trachyte and biotite-bearing ash-flow tuff of Goat Canyon is mapped on Pine Peak and recognized at the observatory. Thirty new whole rock analyses are presented.
We close our guidebook with a visit to the Paisano volcano, a well-exposed, trachytic shield volcano that erupted a compositionally zoned, peralkaline rhyolite-trachyte sequence of lavas and ignimbrites.
Recommended Citation
White, J.C., Rudine, S.F., Parker, D.F., Henderson, G., Urbanczyk, K.M., 2025, Volcanic stratigraphy of the Paradise Mountain Caldera Complex, Davis Mountains, Texas, USA. In: From Orogenies to Hydrology; Geologic Excursions in Texas and Beyond (Z. Fleming and J.M. Cannon, Eds.) Geological Society of America Field Guide, v. 74, in press. https://doi.org/10.1130/2025.0074(05).
Journal Title
Geological Society of America Field Guide
Book Title
From Orogenies to Hydrology; Geologic Excursions in Texas and Beyond
