U.S. Department of the Interior Scientific Investigations Map 3363 U.S. Geological Survey Version 1.1 Pamphlet accompanies map Kgrue Kgrcb Kgrf Kgrcb Kgrb Kkbn Kgrcb Kgrle Kkbn Kgrb Kgrle Kgrcb Kgrf Kgrf Kgrb Kgrf Kgrb Kgrf Kgrf Kgrlb Kgrlb U Kgrle Kgrb D Kgrf Kgrcb Kkbn Kgrle Kgrle Site 2 Kgrb Kgrf Kgrcb Kgrts Kgrf Kgrlb Kgrle Kgrb Kgrb Kgrle Kgrf Kgrd Kgrb Kgrlb Kgrle Kgrts Kgrb Kgrle Kgrb Kgrue Kgrb Kgrr U Kgrlb D Kgrle Kgrf Kgrlb Kgrue U Kgrb D Kgrf D Kgrf Kgrlb Kgrcb Kgrue U D U Kgrts U D Kgrf Kgrb Kgrts Kgrts Kgrd Kgrf Kgrle Kgrle Kgrf Kkbn Kgrlb Kgrb Kgrd Kgrf Kgrlb D Kgrts Kgrlb U Kgrd Kgrts D Kgrf D U Kgrb U Kgrb Kgrd Kgrts Kgrle Kgrcb Kgrts Kgrlb Kgrr Kgrcb U Kgrlb Kgrd Kgrts D Kgrb Khah Kgrr Kgrr Kgrd Kgrts Kgrb Kgrb Site 1 Kcccc Kgrd Kgrd Kkbn Kkbn Kgrf Kgrts Kgrb Kgrlb Kgrlb Kgrts U Kgrts Kgrr Kgrf Kgrf D U Kgrd D Kgrle Kgrd Kgrle Kgrb Kgrhc Kgrlb Kgrf Kgrts Kkbn Kgrb Kgrts Kgrb Kgrb Kgrcb Kgrhc Kgrlb Kgrle Kgrts Kgrlb D Kgrlb Kgrr Kgrhc Kgrlb U Kgrr U Kgrd Kgrue U Kheh D Kgrts D Kgrb Kgrhc Kcccc Kgrlb Kgrd Kgrle D U Kgrr Kgrf Kgrr Kgrts U Kgrd Kgrb Kgrd Kgrb Kgrcb Kcccc D D Kgrf Kgrf U Kgrle Kgrd Kgrlb Kheh U Kgrr D Kgrd Kgrle U D Kgrue Kgrb Kgrd Kgrts Kgrts Kgrle Kgrhc Kgrf Kgrd Kgrf Kgrb Kgrhc Kgrb Kgrd Kgrhc Kgrlb Kgrr Kgrts Kgrb Kgrf U Kgrr Kgrts Kgrlb Kgrr D Kgrue Kgrb Kgrd Kheh Kgrlb Kgrf Kgrb Kgrts Kgrts U Kgrhc D Kgrb Kgrlb Kgrts Kheh Kgrb Kgrf Kgrle U Kgrle Kgrlb D Kgrle Kgrlb Kgrf Kkbn Kgrr Kgrlb Kgrf Kgrlb Kgrlb Kgrd Kgrd Kgrcb Kgrts Kgrf Kgrb Kgrts Kgrlb Kgrue Kgrle Kgrd Kgrle Kgrf Kgrts Kgrr Kgrle Kgrlb Base from U.S. Geological Survey 24,000-scale Blanco, Texas (1965 edition), Kgrlb Field mapping of the hydrostratigraphic units was accomplished on an Apple iPad2 containing geospatially registered 7.5-minute USGS Payton, Texas (1963, 1987 edition), and Rough Hollow, Texas (1963, 1987 edition) 4.5° SCALE 1:24 000 Kgrb topographic maps and utilizing integrated global positioning system (GPS). North American Datum of 1983 (NAD83) 1 1/ 2 0 1 MILE The field data were transferred to Esri ArcMap (Esri, 2014), quality checked, and then used to produce the study area’s hydrostratigraphic map. TEXAS Universal Transverse Mercator Projection, zone 14 10000 1000 2000 3000 4000 5000 6000 7000 FEET Lithologic and hydrostratigraphic descriptions are from field observations and previous investigations. TRUE NORTH MAGNETIC NORTH Digital cartography and GIS database by Diana E. Pedraza. 10.5 1 KILOMETER APPROXIMATE MEAN LOCATION OF QUADRANGLES DECLINATION, 2016 NORTH AMERICAN VERTICAL DATUM OF 1988 Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. DESCRIPTION OF MAP UNITS ii6 Base Twin Sisters Hydrostratigraphic Unit (HSU) Table 1. Summary of the geologic framework, hydrostratigraphy, and ichnology of the Blanco, Payton, and Rough Hollow 7.5-minute quadrangles, Blanco, Comal, Hays, and Kendall Counties, Texas. Although this information product, for the most part, is in the public domain, ii3 Top Doeppenschmidt HSU: Rudist Reef Variant [Period, Epoch, Group, Formation, Members, and lithology modified from Whitney (1952), Lozo and Stricklin (1956), Stricklin and others (1971), Rose (1972), Stricklin and Smith (1973), Amsbury (1974), Inden (1974), Perkins (1974), Clark and others (2010), Blome and it also may contain copyrighted materials as noted in the text. Permission to Edwards Group (upper Lower Cretaceous, Albian)—Overlies the Trinity Group; mudstone, ii1 Clark (2014), Clark and others (2014), and the U.S. Geological Survey National Geologic Map Database, GEOLEX (http://ngmdb.usgs.gov/Geolex). Aquifers from Maclay and Small (1976), Ashworth (1983). Thickness from outcrop, Clark and others (2009), Weirman reproduce copyrighted items must be secured from the copyright owner. wackestone, packstone, grainstone, boundstone, dolomitic limestone, argillaceous limestone, and others (2010), and Clark and others (2014). Hydrogeologic function modified from Clark and others (2009), Weirman and others (2010), Clark and others (2014), and Clark and Morris (2015). Porosity types modified from Choquette and Pray (1970). evaporites, shale, chert. Most removed by erosion. Thickness of remaining Edwards Group 60 ft. ii1 Fabric selective: I, Interparticle porosity; SH, Shelter porosity; MO, Moldic porosity; BU, Burrowed porosity; BP, Bedding plane porosity. Not-fabric selective: FR, Fracture porosity; CH, Channel porosity; BR, Breccia; VUG, vug porosity; CV, Cave porosity. This database, identified as SIM 3363, has been approved for release and Only basal nodular member of Kainer Formation is present in study area publication by the U.S. Geological Survey (USGS). Although this database ii2 *previously published identification for the hydrostratigraphic unit; has been subjected to rigorous review and is substantially complete, the Kainer Formation (late Early Cretaceous, Albian)—Overlies the Trinity Group; mudstones, Trinity **not aerially exposed in the study area] USGS reserves the right to revise the data pursuant to further analysis and wackestone, packstone, grainstone, dolomitic limestone, shale, chert (except in the basal nodular ii1 aquifer review. Furthermore, it is released on condition that neither the USGS nor unit). Most removed by erosion. Thickness of remaining Edwards Group 60 ft. Only basal nodular Geologic framework Hydrostratigraphy ii1 the U.S. Government may be held liable for any damages resulting from its t 98°37’30” 98°30’00” 98°22’30” 98°15’30” 98°07’30” 98°00’00” member of Kainer Formation is present in study area l e authorized or unauthorized use. B 1 l 30°15’00” a Hydrostratigraphic unit VIII—Confining, locally water bearing; bedding plane, fracture r Kkbn ii1 u Thickness TEXAS t Although these data have been processed successfully on a computer c Hydrostratigraphic Hydrogeologic Porosity porosity, and minor cave porosity. Thickness 60 ft u HYEMONUMENT YEAGER HENLY DRIPPING Lithology Aquifer (feet; measured Field identification r t unit (*) function type system at the U.S. Geological Survey (USGS), no warranty expressed or ii2 Epoch Group S at outcrop) HILL CREEK SPRINGS PERIOD Members implied is made regarding the display or utility of the data on any other a G.Q.M. 27 Formation ii1 t Trinity Group (Lower Cretaceous)—Overlies, in the subsurface, Pennsylvanian shale (Imlay, 1940) ii2 i Approximate BLANCO COUNTY thickness (feet) system or for general or scientific purposes, nor shall the act of distribution h Bureau of Economic Depth ii1 c Gamma Hydrostratigraphic units SPR 1:240 in the study area. Contains shale, mudstone to grainstone, boundstone, sandstone, and argillaceous ii2 KENDALL COUNTY a constitute any such warranty. The USGS or the U.S. Government shall not ii1 u Geology (Austin) O HAYS COUNTY be held liable for improper or incorrect use of the data described and/or limestone. Thickness of Trinity Group approximately 635–802 ft ii2 BANDERA COUNTY (Barnes and others, ii1 EXPLANATION 1965) Shaly, nodular limestone; burrowed mudstone and miliolid grainstone: In contained herein. COMAL Massive, nodular and mottled limestone, BRBs2 and orange wisps in ii2 40–60 western Comal County contains oyster reefs of Ceratostreon [Exogyra] VIII 40–60 Confining, locally BP, FR, Glen Rose Limestone (Lower Cretaceous, lower Aptian to middle Albian)—Alternating beds of ii1 COUNTY (Kkbn) freshly broken rock, Ceratostreon [Exogyra] texana 30°07’30” Kainer texana and caprinid biostromes which is the transition to the Walnut Clay water bearing CV Trinity aquifer Edwards Edwards Formation For more information concerning this publication, contact yellowish-tan, medium-bedded limestone and argillaceous limestone with minor evaporite layers. basal nodular ii1 Edwards aquifer of the Fort Terrett Director, USGS Texas Water Science Center Composed of the Lower and Upper Members, separated by a regionally extensive marker bed, Study area CRABAPPLE BLANCO PAYTON ROUGH HOLLOW DRIFTWOOD ii1 U.S. Geological Survey composed of the small fossil identified as Corbula sp. BEXAR USGS 7.5′ quadrangle boundary CREEK fossiliferous BU, BP, Argillaceous wackestone, packstone to miliolid grainstone, argillaceous Alternating beds of limestone and argillaceous limestone; fossils rare; 1505 Ferguson Lane Edwards aquifer COUNTY Camp Bullis (B) 220–230 Confining FR, occasional ii2 Balcones fault zone (most intensely faulted area) limestone; burrowed (Kgrcb) stair-step topography Austin, Texas 78754–4501 Upper Member (Lower Cretaceous, lower to middle Albian)—Massive shale, claystone, CV Sites mentioned in the text (512) 927-3500 evaporites, siltstone, mudstone, wackestone, packstone, grainstone, boundstone and argillaceous ii1 Balcones Dissolved evaporites, highly altered crystalline limestone and chalky limestone. Locally 300–390 ft thick. Composed of the following hydrostratigraphic units in Springs mentioned in the text Weathers to an orangish red pebbly texture, often has less cedar growth Or visit the Texas Water Science Center Web site at ii2 Figure 8. Photograph showing a close-up of the conglomerate/breccia bed at mudstone, breccia; commonly contains boxwork voids where the Upper evaporite (C) fault zone 0–10 Aquifer I, MO, BR and hardier, more abundant grasses, boxwork structure, springs and seeps http://tx.usgs.gov/ descending stratigraphic order: Cavernous (Kgrc), Camp Bullis (Kgrcb), upper evaporite 30°00’00” the base of the Hensell Sand at site 1 alongalong the Blanco River,River, western HaysHays evaporites have been dissolved (Kgrue) ii1 lower evaporite