The geology of Central Texas has been extensively studied in the past. This previous work serves as a foundation for the more detailed and, hopefully, more precise geologic characterization of the MCQ presented in this website. The objective here is to acknowledge past studies with a list and brief summary and, where possible, a link to the original source. The list begins with Dr. Grimshaw’s Ph.D. dissertation and M.A. thesis. Selected additional references follow in (more or less) order of relevance.
[In preparation]
Ph.D. Dissertation:
Environmental Geology of Urban and Urbanizing Areas:
A Case Study from the San Marcos Area, Texas
Dr. Grimshaw’s interest in the geology of the MCQ and SMNQ goes back to the 1970s. When he returned to UT to study for the Ph.D., he chose a career in environmental geology, which he began with Dr. Keith Young as his supervisor. Dr. Grimshaw’s dissertation utilized the San Marcos area as a case study in the rapidly-growing Austin-to-San-Antonio growth corridor. The dissertation has two major components – detailed geologic mapping followed by an environmental analysis that focused on land capability to support various human uses of the land. The area covered is the southern 1/3 of the Mountain City Quadrangle, all of the San Marcos North Quadrangle, and the upper 2/3 of the San Marcos South Quadrangle.
Grimshaw, T., 1976, Environmental Geology of Urban and Urbanizing Areas: A Case Study from the San Marcos Area, Texas. Department of Geological Sciences, The University of Texas at Austin. Unpublished Dissertation.
Richard Smith M.A. Thesis
[Abstract in preparation]
Smith, R., 1968, Geology of the Buda-Kyle Area, Hays County, Texas: University of Texas at Austin, Unpublished Thesis.
MAP (Complete)
MAP (Buda Quadrangle Portion)
UT Bureau of Economic Geology Report of Investigation #86
Abstract
This report was first published in 1976 and has been reprinted many times. It is available in book form by request.Excerpted from the IntroductionThe area described in this report comprises 712 square miles centered on the City of Austin. The area extends north almost to Round Rock, south to the vicinity of Buda, east to just beyond Manor, and west to about 5 miles west of Oak Hill. It includes approximately 604 square miles of Travis County, 38 square miles of Hays County, 18 square miles of Bastrop County, and 52 square miles of Williamson County. The aim of this publication is to supply geologic information that can be used to prevent or minimize problems that arise during urban development. A series of maps has been constructed for this purpose; the maps illustrate distribution of topographic conditions, soils, surface drainage, physical properties, rock types, land use, and vegetation.Base maps were compiled from 7.5- and 15-minute U. S. Geological Survey topographic maps and a 1970 edition of a map of the City of Austin. Basic geologic mapping was completed on aerial photographs at a scale of 1:20,000. Supplementary maps were prepared by combining data from the basic geologic map with soils, engineering, topographic, and vegetation data. Final maps were constructed at scales of 1:62,500 (approximately 1 inch equals 1 mile) and 1:125,000 (approximately 1 inch equals 2 miles).
Garner, L., and K. Young, 1976. Evironmental Geology of the Austin Area: An Aid to Urban Planning. The University of Texas at Austin, Bureau of Economic Geology, Report of Investigations No. 86, 39 p.
Kolb Thesis on Signal Hill Quadrangle
ABSTRACT
The Signal Hill Quadrangle is located astride the Balcones Escarpment southwest of Austin. Cretaceous rocks (Albian and Cenomanian) cropping out in the area include the upper two members of the Glen Rose Formation, the Bull Creek and Bee Cave Members of the Walnut Formation, the Kainer and Person Formations of the Edwards Group, and the Georgetown, Del Rio, and Buda Formations. Deposition represented by these formations ranges from supertidal to tidalflat to open-shelf marine environments. At one location there is a basalt plug, probably of Senonian age. The youngest deposits in the quadrangle are those associated with Quaternary terraces and alluvial sands and gravels. The faults mapped are part of the Balcones Fault Zone, a system of ~ echelon, northeast-trending, predominantly normal, dip-slip faults. This system was probably active in the middle Tertiary. The Mt. Bonnell Fault is the most important fault in the quadrangle. It is one of the major faults of the Balcones Fault System, having been downthrown 170-350 feet to the southeast. The total displacement of all faulting in the map area is about 800 feet.
Kolb, R., 1981. Geology of the Signal Hill Quadrangle, Hays And Travis Counties, Texas. Department of Geological Sciences, The University of Texas at Austin. Unpublished Thesis.
Collins Map of Driftwood Quadrangle (BEG Open File Report)
Collins, E.W., 2002, Geologic map of the Driftwood quadrangle, Texas: University of Texas at Austin, Bureau of Economic Geology, Open-File Map STATEMAP Study Area 9, scale 1:24,000.
U.S. Geological Survey Hydrostratigraphic Map of Part of Hays County
[In preparation]
M.A. Thesis
Geology of the Wimberley Area, Hays and Comal Counties, Texas
Abstract
Cretaceous limestone, marl, and dolomite of Late Aptian to Middle Albian age crop out in the Wimberley area, a 5-minute by 10-minute quadrangle in central Texas situated in the dissected eastern margin of the Edwards Plateau. Formations exposed are the upper part of the Glen Rose, the Walnut, and the lower part of the Edwards. The Glen Rose, which crops out over 90% of the area, is subdivided into 7 informal members defined on mappability on aerial photographs. Six major step faults of the Balcones fault zone transect the area, displacing the strata downward to the southeast about 700 feet. The outstanding geomorphic features are the high relief hills and ridges south of the Blanco River, which are caused by dissection along the Edwards Plateau margin, and the deflections of Cypress Creek and Blanco River where they cross faults.
Grimshaw, T., 1970. Geology of the Wimberley Area, Hays and Comal Counties, Texas. Department of Geological Sciences, The University of Texas at Austin. Unpublished Thesis.