Browsing by Subject "Geology -- Texas -- Blanco County -- Maps"

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Geologic map of the Hye quadrangle, Blanco, Gillespie, and Kendall Counties, Texas
(University of Texas at Austin. Bureau of Economic Geology, 1965) Barnes, Virgil E. (Virgil Everett), 1903-1998
Hye quadrangle includes part of the southeastern Llano region and part of the eastern margin of the Edwards Plateau where most of the Plateau surface has been destroyed by erosion. In the southern part of the quadrangle a narrow lobe of the Edwards Plateau trends east-northeastward from near the southwest quadrangle corner. The area to the north is in the broad gently rolling Pedernales River basin, and that to the south is in a fairly rugged marginal part of the Blanco River drainage area. The geology of the Hye quadrangle is shown on a U. S. Geological Survey 7%-minute topographic quadrangle map and, following the Johnson City quadrangle (Barnes, 1963), is the second geologic map in the Llano region to appear on a modern 1:24,000 scale, 20-foot contour interval base. The relief in the quadrangle is about 591 feet; elevations range from about 1,362 feet where Pedernales River leaves the quadrangle to 1,953 feet near the southwest corner of the quadrangle. About 80 percent of the Hye quadrangle is drained by Pedernales River, mostly through two main tributaries, Williamson and Rocky Creeks, both of which have three forks-East, Middle, and West-and numerous named and unnamcd tributaries. The remaining 20 percent of the quadrangle drains to Blanco River by way of Klepac Creek, Stiner Creek, Murry Branch, Roman Branch, and various unnamed branches. During the time the geology of this area was being mapped, Klepac Creek was known as North Big Creek and Stiner Creek as West Big Creek. Hye quadrangle is high on the southeastern side of the Llano uplift. Cambrian and Ordovician rocks are represented by about 1 square mile of outcrop. Cretaceous rocks and small Quaternary surficial deposits occupy the remainder. The Cambrian and Ordovician rocks exposed in the northeastern part of the quadrangle dip southeastward at angles up to about 5O, and the relatively flat-lying Cretaceous rocks dip eastward about 10 feet per mile. Discussion of stratigraphic, structural, economic, and geophysical problems are in cited references. This publication on the Hye quadrangle is one of a series of central Texas geologic quadrangle maps which will be compiled as topographic bases become available. An index map for geologic maps already published on planimetric bases and others planned for ~ublication on the new topographic bases is shown with the geologic map. During the period 1939 to 1942, the writer, assisted by Louis Dixon, mapped geologically the western one-third of the Hye quadrangle in Gillespie and Kendall counties. Mapping of the remainder of the quadrangle area, in Blanco County, was done intermittently with assistance from L. E. Warren (1942-194,G) and A. R. Palmer (1947- 1948). A gravity survey of the quadrangle was completed during 1946-1948 with the aid of Louis Dixon and A. R. Palmer.