older alluvial deposits (TXQao;0)

State	Texas
Name	older alluvial deposits
Geologic age	Phanerozoic \| Cenozoic \| Quaternary \| Pleistocene
Original map label	Qao
Comments	Alluvium, colluvium, and caliche on surfaces dissected by modern drainage in Trans-Pecos, Presidio, Van Horn, and El Paso areas; pebbles, cobbles, boulders up to 4 ft in size, and sand; unconsolidated to pertly consolidated by calche cement; composed of chert, quartzite, limestone, and volcanic rocks of vesicular, aphanitic, and porphyritic textures.
Primary rock type	gravel
Secondary rock type	sand
Other rock types	silt
Lithologic constituents	Major Unconsolidated > Coarse-detrital (Alluvial) Minor Unconsolidated > Fine-detrital (Alluvial)
Map references	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
Unit references	Bureau of Economic Geology, 1979, Emory Peak--Presidio Sheet, Geologic Atlas of Texas, University of Texas at Austin.
Geographic coverage	Andrews - Brewster - Culberson - El Paso - Hudspeth - Jeff Davis - Loving - Pecos - Presidio - Reeves - Terrell - Val Verde - Ward