| State | Texas |
|---|---|
| Name | Duff Formation, Decie Member from Paisano caldera |
| Geologic age | Early Oligocene |
| Lithologic constituents |
Major
Igneous > Volcanic > Felsic-volcanic > Trachyte
Minor
Igneous > Volcanic > Felsic-volcanic (Pyroclastic-ash flow)
Incidental
Sedimentary > Clastic > Conglomerate
|
| Comments | volcanic rock from Paisano volcano, 5 units, young to old: 1) lava, agglomeratic tuff, conglomerate, ash-flow tuff. 2) ash-flow tuff. 3) aphyric to sl. porphyritic quartz trachyte 4) yellow aggomeratic tuff interlayered with two minor quartz trachyte ash-flow sheets 5) rhyolite lava |
| References | Bureau of Economic Geology, 1982, Fort Stockton Sheet, Geologic Atlas of Texas, University of Texas at Austin, scale 1:250,000.Bureau of Economic Geology, 1992, Geologic Map of Texas: University of Texas at Austin, Virgil E. Barnes, project supervisor, Hartmann, B.M. and Scranton, D.F., cartography, scale 1:500,000. |
| NGMDB product | |
| Counties | Brewster - Jeff Davis - Presidio |