FT25CN401. An Educator's Look at West Texas Geology. Thu–Sat. 16–18 Oct, 12 p.m. (first day), 9 a.m. (last day); US$470 for students and ECPs; $510 for professionals. CEUs 1.6.
Location: El Paso, Texas, USA
Endorsed by NAGT (Geo2YC), GSA’s Structural Geology and Tectonics, Geoscience Education, Quaternary Geology and Geomorphology, Environmental and Engineering Geology Divisions
Led by: Joshua Villalobos, Callan Bentley
This tour highlights the geological wonders between El Paso and San Antonio, emphasizing the Franklin Mountains, Guadalupe Mountains, and Carlsbad Caverns. Participants will explore tectonic, sedimentary, and karst landscapes. We plan a day and a half in the field exploring these sites as well as “meta” level discussions about field trip organization and facilitation. We hope for vibrant and rich discussions set in some of the most mind-blowing geological sites of west Texas. Cost includes transportation (mini vans), two nights at the Hilton Garden Inn El Paso (double occupancy), meals, snacks, and water.

FT25CN402. Architecture of a Seismic-Scale Normal Fault Zone: The Hidden Valley Fault, Canyon Lake Gorge, Texas. Thu. 23 Oct, 8 a.m.–5 p.m; US$95. CEUs 0.8.
Endorsed by GSA’s Environmental and Engineering Geology, Structural Geology and Tectonics, Quaternary Geology and Geomorphology Divisions
Led by: David Ferrill, Adam Cawood
This field trip focuses on fault zone architecture and deformation processes in the seismic-scale Hidden Valley fault zone at Canyon Lake Gorge, part of the Balcones fault system. Located approximately one hour from San Antonio, Texas, this is an exceptionally well-exposed site to observe fault and fracture networks in mechanically layered carbonates of the Cretaceous Glen Rose Formation. The Hidden Valley fault zone has provided a study area for deformation analyses for over two decades and is an excellent analog for deformation and fluid flow in mechanically layered reservoirs and aquifers. Cost includes transportation (mini vans), entrance fees, lunch, snacks, and water.

FT25CN403. Building San Antonio: Geology, water and building resources in the historic 'Valley of the Missions'. Sat. 18, Oct. 8:30 a.m.–5 p.m. US$95. CEUs 0.8.
Endorsed by GSA’s Environmental and Engineering Geology, Geoscience Education, History, Philosophy, and Geoheritage, Geoarchaeology, Quaternary Geology and Geomorphology Divisions
Led by: Thomas Ewing, John Long
The valley of the San Antonio River was the focus for the foundation of five Spanish mission complexes (1718-1731, now a World Heritage Site) and civilian settlement.The valley provided irrigable land, steady water supplies, and varied materials for building. This trip provides an overview of these resources, and how they shaped the early settlement of the 'Valley of the Missions' and the city of San Antonio.We will visit springs, acequias, quarries in limestone and tufa, downtown and mission structures. Results of recent mapping of the San Antonio quadrangle will be included. Cost includes transportation (bus), lunch, snacks, and water.

FT25CN404. Cambrian Earth systems in western Laurentia and Tonto Group of the western Grand Canyon Region. Wed.–Sat. 15–18, Oct. 5:00 p.m. (first day); 12 p.m (last day). US$800. CEUs 2.4.
Location: Las Vegas, Nevada, USA
Endorsed by GSA’s Geochronology Division,
Led by: Carol Dehler, Karl Karlstrom, Stephen Rowland
In honor of Fred Sundberg - tied to his session - nee
Explore the iconic Cambrian Tonto Group strata in westernmost Grand Canyon and near Las Vegas to discuss results of new research and implications for long-standing questions about Cambrian Earth systems. Topics include the Sauk transgressions, the Great Unconformity, Cambrian subsidence mechanisms, a sequence stratigraphy re-interpretation of Eddie McKee’s classic Tonto Group stratigraphy, new biochronology, precise geochronology, and C-isotope chemostratigraphy. How do new datasets from the Grand Canyon inform understanding of the Cambrian Earth System and its rapid, ever-shrinking Time Scale? Cost includes transportation (mini vans), one night in Las Vegas (double occupancy) and two nights at the Dude Ranch (double occupancy) which includes meals, snacks and water, and boat usage.

FT25CN405. Cave monitoring in central Texas: Insights into paleoclimatology, karst vadose zone hydrogeology, and cave geomorphology. Sat.18, Oct. 7:30 a.m.–6 p.m. US$40 for students and ECPs; US$60 for professionals. CEUs 0.8.
Endorsed by GSA’s Hydrogeology, Environmental and Engineering Geology, Geoarchaeology, Quaternary Geology and Geomorphology Divisions
Industry track: Hydrogeology and Environmental Geology
Led by: Jay L. Banner, Alexander Janelle
We will visit two central Texas caves, Cave Without a Name and Natural Bridge Caverns, which have been studied as a part of the longest-running cave monitoring program in the world. Led by Professor Jay Banner and PhD student Alex Janelle, participants will be brought to both caves to discuss insights from cave monitoring and paleoclimate studies. Participants will be taken through the geologic history of Texas, from the significant events leading to development of the caves to modern processes occurring above the cave. Texas BBQ will be provided for lunch (dietary restrictions accommodated). Cost includes transportation (school vehicles), lunch, snack, and water.

FT25CN406. Cretaceous of the Trans-Pecos: Effects of Eustacy, Bottom-Water Chemistry, Karsting, and Tectonics on Carbonates and Mudrocks. Thu –Sat. 23–25, Oct. 7:30 a.m.–6 p.m. US$355. CEUs 2.4.
Endorsed by GSA’s Geochronology Division
Led by: Richard Denne, Toti E. Larson, Tingwei Ko
This trip examines the spectacular outcrops exposed in the Trans-Pecos region.The trip focuses on the organic-rich marlstones and limestones of the Boquillas, and includes discussions on OAE2, bottom-water chemistry, fracture patterns and structure, and eustacy, which are compared to the equivalent subsurface Eagle Ford.The trip also examines karsting in the rudist-rich Devil’s River Ls, thickness and stacking patterns of the Del Rio and Buda, and fractures and channels in the Austin Chalk.Hikes are short except for the tour of the Fate Bell Shelter in Seminole Canyon State Park. Cost includes transportation (mini vans), two nights at the Ramada Inn Del Rio (double occupancy), park entrance fees, lunch, snacks, and water.

FT25CN407. Energizing the Future: Innovative Energy Production and Environmental Stewardship in Texas. Sat. 18, Oct. 7:30 a.m.–6 p.m. US$25. CEUs 0.8.
Endorsed by UT Austin’s Choose Energy K-12 Outreach Program, Railroad Commission of Texas, GSA’s Geology and Health, Structural Geology and Tectonics,Environmental and Engineering Geology Divisions
Led by: Sabrina Ewald, Tiffany Cotledge, Hilary Olson, Jon Olson
This field trip for 5th to 12th grade teachers and university students explores subsurface energy technology and innovation. Participants will visit San Antonio field sites to learn about energy resource engineering and geology, and explore energy sector careers. Organized by UT Austin’s Choose Energy K-12 Outreach Program and the Railroad Commission of Texas, the trip includes 8 CPE hours for teachers, lunch, and transportation. The sponsorship will cover most costs associated with the trip other than lunch, snacks, and water.

FT25CN408. Exploring The K/Pg Boundary in the Gulf of Mexico at the Brazos River Outcrops and the Gulf Coast Core Repository. Sat. 18, Oct. 6 a.m.--7 p.m. US$80 for students and ECPs; US$100 for professionals. CEUs 0.8.
Endorsed by GSA’s Planetary Geology, Geochronology, Mineralogy, Geochemistry, Petrology, and Volcanology, Continental Scientific Drilling Divisions
Led by: Christopher Lowery, Sean P.S. Gulick, Pim Kaskes, James Witts
We propose to explore K/Pg boundary deposits across the Gulf of Mexico, with stops at the outcrops along the Brazos River near Rosebud, TX and the IODP Gulf Coast Repository (GCR) in College Station, TX. Brazos River outcrops contain cross-stratified sandstone likely formed by a tsunami, interbedded with layers of impact spherules and overlain by a ~3 m succession of early Paleocene marine sediments recording the recovery of life. Cores at the GCR from the Chicxulub crater, Gulf of Mexico and Caribbean record impact processes and environmental changes at different distances from the crater. Cost includes transportation (bus), breakfast, lunch, snacks, and water.

FT25CN409. Exploration of the Balcones Escarpment: Its Hydrogeologic Evolution and Geoheritage Attributes.Sat. 18 Oct, 8 a.m.–5 p.m. US$145 for students and ECPs; $185 for professionals. CEUs 0.8.
Endorsed by GSA’s Hydrogeology, History, Philosophy, and Geoheritage, Geoarchaeology, Structural Geology and Tectonics, Quaternary Geology and Geomorphology, Environmental and Engineering Geology Divisions
Led by: C. M. Woodruff Jr., Linda Ruiz McCall, Patrick L. Abbott, Carson W. Werner
The Major Springs of the Balcones Escarpment composea Texas Geoheritage site known for its scientific, aesthetic, educational, and cultural value. Join us for a field trip along this geologic borderland focusing on karst hydrogeology, evolution of the landscape, and cultural history. The trip includes traverses acrossthe Balcones Escarpment, visits to San Marcos, Comal, and San Pedro Springs, and views of the historic Mission San José, a National Historic Site. We will also visit Natural Bridge Caverns. Cost includes transportation (charter bus), lunch, snacks, water, and park fees.

FT25CN410. Guadalupe Mountains and Carlsbad Caverns National Parks: An Exploration of Capitan's Permian Fossil Reef. Thu–Sat. 16–18 Oct, 6:30 a.m. (first day) – 4 p.m. (last day). US$550. CEUs 2.4.
Endorsed by GSA’s History, Philosophy, and Geoheritage, Geochronology Divisions
Led by: Spencer Cody, Jill Cody
Join us on an exciting three-day adventure as we explore the remarkable limestone formations of the Permian Capitan Reef. Day one will begin at the convention center on our way to Guadalupe Mountains NP with stunning views of Guadalupe Peak and El Capitan staying in Carlsbad both nights. Day two will be below ground with a natural cave entrance tour of Carlsbad Caverns and of the remarkable Big Room, while spending the afternoon exploring the Salt Basin Dunes. Day three we will return attendees to the San Antonio convention center. All lodging, meals, and fees are covered for the three days. Cost includes transportation (15 -passenger van), two nights at the Sleep Inn Carlsbad, New Mexico (double occupancy), meals, snacks, and water.

FT25CN411. Investigating Confirmed and Suspected Impact Sites in Western and Central Texas. Thu–Fri. 23–24 Oct, 8 a.m. (first day) – 5 p.m. (last day). US$260 for students and ECPs; US$300 for professionals. CEUs 1.6.
Endorsed by GSA’s Planetary Geology, Mineralogy, Geochemistry, Petrology, and Volcanology Divisions
Led by: Steven Jaret, R. Scott Harris
This trip provides a great opportunity to bridge terrestrial and extraterrestrial geology through the lens of impact sites. We will visit two confirmed impact craters of drastically different size and style: the ~8-mile diameter Sierra Madera structure near Fort Stockton and the Odessa crater and meteorite field in Ector County. It also will visit two proposed structures: Bee Bluff, south of Uvalde, and Hico, southwest of Fort Worth. We will discuss impact geology and terrestrial structures as planetary analogues. Cost includes transportation (full size SUVs), one night in Fort Stockton (double occupancy), lunch, snacks, and water.

FT25CN412. Kilbourne Hole and the Potrillo Volcanic Field: A Planetary Analog Site. Fri–Sat. 17–18 Oct, 8 a.m. (first day) – 5 p.m. (last day). US$250 for students and ECPs; US$300 for professionals. CEUs 1.6.
Endorsed by GSA’s Planetary Geology, Mineralogy, Geochemistry, Petrology, and Volcanology Divisions
Location: El Paso, Texas, USA
Led by: Jose Miguel Hurtado, Tara Sweeney
Kilbourne Hole, a Quaternary maar volcano inthe Potrillo volcanic field of south-central New Mexico, has been the subject of several past and ongoing planetary analog studies and has served as a training site for both the Apollo and Artemis lunar exploration programs. On this field trip, we will study thephysical volcanology of Kilbourne Hole and its surroundings, its place in the regionalcontext of the southern Rio Grande Rift, and the unique lunar and planetary scienceperspectives it offers. Cost includes transportation, one night at the Fairfield Inn & Suites El Paso (double occupancy), lunch, snacks, and water.

FT25CN413. Kirk Bryan Field Trip: Quaternary Landscape Evolution, Soils, and Geoarchaeology in the Medina River Valley, South-Central Texas (Half Day). Sat. 18 Oct, 7:30 a.m.–1:30 p.m. US$0 for the first 10 students; US$45 for professionals. CEUs 0.6.
Endorsed by GSA’s Quaternary Geology and Geomorphology, Geoarchaeology, Soils and Soil Processes, Environmental and Engineering Geology, History, Philosophy, and Geoheritage, Geochronology Divisions, Kansas Geological Survey
Led by: Rolfe D. Mandel, Lee C. Nordt
This trip will include the Kirk Bryan Field Trip in the morning and conclude with the Geoarchaeology Field Trip in the afternoon. The Kirk Bryan Field Trip will focus on Quaternary landscape evolution, soils, and geoarchaeology in the Medina River valley at the deeply stratified Richard Beene archaeological site on the south side of San Antonio. The sequence of cultural and alluvial deposits at the site is one of the most complete records of Holocene human occupation and sedimentation documented in North America and is very important to the interpretation of the cultural history of the Inner Gulf Coastal Plain and adjacent areas of the Southern Plains. The trip to San Marcos Springs in Hay County, Texas will highlight a significant landscape for geological, hydrological, and archaeological interests. The artesian springs are among the largest in Texas and provide an exceptional opportunity for GSA attendees to study aquifer dynamics, karst geomorphology, and human history. This field trip proposes to lead attendees on a glass bottom boat tour, hiking tour of the fault zones of the escarpment, and tour of the cultural materials recovered over the years at the archaeological site. This trip is partially funded by the Geoarchaeology Division and the Kansas Geological Survey. The cost includes transportation (bus), boat fees, lunch, snacks, and water.

FT25CN414. Kirk Bryan Field Trip & The Hydrology of the Edwards Aquifer and the Geoarchaeology of Spring Lake, South-Central Texas (Full Day). Sat. 18 Oct, 7:30 a.m.–6:00 p.m. US$0 for the first 10 students and/or ECPs; US$85 for professionals. CEUs 0.8.
Endorsed by GSA’s Geoarchaeology, Environmental and Engineering Geology, Soils and Soil Processes, History, Philosophy, and Geoheritage, Hydrogeology, Limnogeology Divisions, Kansas Geological Survey
Led by: Samantha Marie Krause, Rolfe D. Mandel
This trip will include the Kirk Bryan Field Trip in the morning and conclude with the Geoarchaeology Field Trip in the afternoon. The San Marcos Springs in Hay County, Texas are part of a significant landscape for geological, hydrological, and archaeological interests. The artesian springs are among the largest in Texas and provide an exceptional opportunity for GSA attendees to study aquifer dynamics, karst geomorphology, and human history. This field trip proposes to lead attendees on a glass bottom boat tour, hiking tour of the fault zones of the escarpment, and tour of the cultural materials recovered over the years at the archaeological site. This trip is partially funded by the Geoarchaeology Division and the Kansas Geological Survey. The cost includes transportation (bus), boat fees, lunch, snacks, and water.

FT25CN415. Regional Perspective of the Eagle Ford and Austin Chalk Groups in and around San Antonio. Thu-Sat. 16-18, Oct. 12 p.m. (first day) – 5:30 p.m. (last day). US$375 for students; US$475 for professionals. CEUs 2.0.
Endorsed by
Led by: Michael Pope, Arthur D. Donovan, John Cooper, Christine Griffith, Alexis Godet
Survey outcrops of the Eagle Ford and Austin Groups in and around San Antonio, to show off their sequence stratigraphy and regional correlations into the subsurface. Cost includes transportation (bus), lunch, dinner on night one, snacks, water, one night at the Ramada Inn Del Rio (double occupancy), and one night stay in San Antonio (double occupancy).

FT25CN416. San Miguel Lignite Mine Tour. Sat. 18 Oct, 7:30 a.m.–6:00 p.m. US$99 for students and ECPs; US$140 for professionals. CEUs 0.8.
Endorsed by AEG Texas Chapter, GSA’s Geology and Health, Environmental and Engineering Geology, Structural Geology and Tectonics Divisions
Led by: Benson Chow, Jeffrey Neathery, Skye Ibarra
The Association of Environmental & Engineering Geologists (AEG) Texas Chapter will run a tour of the San Miguel lignite mine in Christine, Texas. This South Texas mine is currently in operation under the North American Construction Group. The morning will cover talks about the history of the mine itself, the geology and site planning of the area, and the environmental permitting and reclamation process through the future. After lunch, we'll be taking a tour of the active mine site for an up close look! PPE: safety glasses, hardhats, closed toe or steel toe boots, high visibility vest. Cost includes transportation (bus), lunch, snacks, and water.

FT25CN417. Sedimentologic, Biostratigraphic and Chemostratigraphic Insights into the Wilcox Group: Implications for Stratigraphic Correlations, Depositional Trends, Paleoclimate and CO₂ Storage. Fri-Sat. 17-18 Oct. 8 a.m.–5 p.m. US$310 for students; US$350 for professionals. CEUs 0.8.
Endorsed by GSA’s Geochronology, Environmental and Engineering Geology, Soils and Soil Processes Divisions
Industry Tracks: Energy
Location: Austin, Texas, USA
Led by: Peter Flaig, Mariana Olariu, Cornel Olariu, Carlos Uroza, William A. Ambrose
The core workshop aims to instruct the attendants on the sedimentology and stratigraphy of the Wilcox Group, onshore Texas. Several key drill cores, associated wireline well-logs, and palynological and geochemical datasets are used to illustrate the dominant sedimentary processes, depositional system evolution, and provide insights into paleoclimate, paleogeography, and the potential for regional correlation. Petrophysics will provide estimates of the reservoir properties and assessment of the controls on reservoir quality and feasibility for CO2 storage. The field course focuses on Paleocene-Eocene Thermal Maximum (PETM) deposits of the Wilcox group near Bastrop, TX. This is an extension of the core workshop and will allow participants to see laterally-extensive outcrops that contain some of the facies they saw in core. The goal is to examine sedimentologic, ichnologic, biostratigraphic, isotopic, and geochemical trends within the PETM interval and overlying Carrizo Sandstone, discuss paleoenvironmental evolution, and propose regional correlations based on this new dataset. Outcrops will provide the opportunity to discuss stratal architectures and examine key surfaces that are not evident in drill core. Cost includes transportation for the field trip on day 2 (bus), one night hotel stay in Austin, Texas (double occupancy), use of materials at the facility, lunches, snacks, and water.

FT25CN418. Subduction, underplating, and exhumation in a hot subduction zone. Wed–Sat. 15–18 Oct, 8:45 a.m. (first day) – 8:45 a.m. (last day). US$399 for students and ECPs; US$480 for professionals. CEUs 2.4.
Location: Santa Catalina Island, California, USA
Endorsed by GSA’s Structural Geology and Tectonics, Mineralogy, Geochemistry, Petrology, and Volcanology Divisions
Led by: John P. Platt, Frances Cooper, Justine Grabiec
The trip will explore the structure and petrology of the Catalina Schist terrane on Santa Catalina Island, California. The island exposes rocks of oceanic origin metamorphosed under various grades from lawsonite-blueschist to upper amphibolite/eclogite, in a series of tectonic slices, separated in part by ultramafic melange carrying high-grade blocks. The trip will consider the implications of the inverted metamorphic sequence and the significance of the tectonic contacts in terms of the thermal and mechanical evolution of the subduction complex during subduction, underplating, and exhumation. Cost includes transportation from the airport (shuttle), to the island (boat), bunk space at the Wrigley Center, and meals.

FT25CN419. The 10th Texas Hydro~Geo Workshop. Sat. 18 Oct, 6 a.m.-10 p.m. US$130. CEUs 1.6.
Endorsed by GSA’s Hydrogeology, Geoinformatics and Data Science, Environmental and Engineering Geology, Geology and Health Divisions
Led by: Geary Schindel, Sriram Madabhushi
The Texas Hydro~Geo Workshop is centered on the collection, processing, analysis and evaluation of hydrologic, geologic, and biologic field data. The workshop serves as an excellent introduction for aspiring geology, hydrology, wildlife biology, and environmental science students, as well as seasoned professionals. The event is in its 10th year and has been popular with college level STEM students. Approximately 40 separate modules will be presented ranging from field safety, map reading, GPS use, water samples, stream gauging, tracer testing, etc. Prepare yourselves for a unique evening of yodeling, hog calling, and a 7 p.m. night lecture inside a cave (125 steps in and out). Visit the workshop at www.hydrogeoworkshop.org. Cost includes transportation (bus), lunch, and meeting registration (includes dinner).

FT25CN420. The Edwards Aquifer of South-Central Texas - An Aquifer Under Stress. Thu. 23 Oct, 8 a.m.–6 p.m. US$65 for students; $95 for professionals. CEUs 0.8.
Endorsed by GSA’s Geology and Health, Hydrogeology, Geoscience Education, Environmental and Engineering Geology Divisions
Led by: Geary Schindel, Ronald Green, Allan Clark, Jesse Chadwick
The Balcones Fault Zone segment of the Edwards Aquifer in south-central Texas is one of the most productive aquifers in the U.S. The San Antonio segment extends a distance of approximately 180 miles. The aquifer is the primary source of water for 2.1 million people and agriculture and industry in the region. The San Antonio area is one of the fastest growing areas in the U.S. The field trip will visit the Contributing, Recharge, and Artesian zones and discuss development, water quality, recharge and drought, endangered species issues in this important karst aquifer. Cost includes transportation (bus), lunch, snacks, and water.

FT25CN421. On to the Future (OTF): The Flow of Sustainability: Inside the San Antonio Water System (Saturday). Sat. 18 Oct. Time TBD. $30 for students; $75 for professionals. CEUs 0.4.
Endorsed by GSA On to the Future, GSA’s Hydrogeology, Geology and Health, Environmental and Engineering Geology, Quaternary Geology and Geomorphology Divisions
Led by: Jennifer Adkins Schudrowitz
Explore the innovative water management strategies of the San Antonio Water System (SAWS), a leader in conservation and sustainability. This field trip offers a behind-the-scenes look at SAWS facilities, including groundwater, desalination, and recycling operations. Learn about the region’s unique hydrogeology, the Edwards Aquifer, and how SAWS balances urban demand with environmental stewardship. Ideal for those interested in water resources, infrastructure, and policy, this trip provides insight into cutting-edge solutions for sustainable water management. Cost includes transportation (bus), snacks, and water.

FT25CN422. The Flow of Sustainability: Inside the San Antonio Water System (Wednesday Afternoon). Wed. 22 Oct, 1 p.m. – 5 p.m. $30 for students; $75 for professionals. CEUs 0.4.
Endorsed by GSA’s Hydrogeology, Geology and Health, Environmental and Engineering Geology, Quaternary Geology and Geomorphology Divisions
Led by: Jennifer Adkins Schudrowitz, Heather Ginsburg
Explore the innovative water management strategies of the San Antonio Water System (SAWS), a leader in conservation and sustainability. This field trip offers a behind-the-scenes look at SAWS facilities, including groundwater, desalination, and recycling operations. Learn about the region’s unique hydrogeology, the Edwards Aquifer, and how SAWS balances urban demand with environmental stewardship. Ideal for those interested in water resources, infrastructure, and policy, this trip provides insight into cutting-edge solutions for sustainable water management. Cost includes transportation (charter bus), snacks, and water.

FT25CN423. Volcanic stratigraphy of the Paradise Mountain-Pine Peak Caldera Complex, Davis Mountains Volcanic Field, Texas. Thu–Sat. 16–18 Oct. 8 a.m.–5 p.m. US$399 for students and US$450 for professionals. CEUs 2.4.
Endorsed by GSA’s Mineralogy, Geochemistry, Petrology, and Volcanology, Planetary Geology, Structural Geology and Tectonics, Geochronology Divisions
Led by: John White, Shannon F. Rudine, Don F. Parker, Gary Henderson, Kevin Urbanczyk
Our field trip incorporates recent field mapping and petrologic analysis of the Paradise Mountain Caldera Complex. The first day will provide the participant with an overview of the Davis Mountains Volcanic Field, from Balmorhea to Alpine. The second day will focus on the Caldera Complex, with emphasis on the revelations from new mapping on Mounts Locke and Fowlkes at the McDonald Observatory. Most of the day will be spent examining outcrops of units exposed along the roads and on short hikes at McDonald Observatory. There will be three short stops before returning on the third and final day. Cost includes transportation (15-passenger vans), lunch, snacks, water, and two nights at The Holland Hotel (double occupancy).

FT25CN424. Walking in the footprints of giants: dinosaur tracks and trackways in Albian series of the San Antonio region. Fri–Sat. 17-18 Oct, 8 a.m.–6:30 p.m. US$230 for students and US$290 for professionals. CEUs 1.6.
Sponsored by Paleontological Society
Endorsed by GSA’s Geochronology Division
Led by: Thomas Adams, Dianna Price, Alexis Godet, Daniel Lehrmann, Asmara Lehrmann
Dinosaurs are some of the best ambassadors for geoscience to the public, yet their iconic footprints in the rock record of Central Texas are at risk to disappear because of urbanization and climate change that augment weathering, and intense flooding events. Our 2-day long field trip will include several famous sites of tracks and trackways in the stratigraphy of central Texas, at Canyon Lake Gorge, the Heritage Museum of the Texas Hill Country, the Mayan Dude Ranch, and the Davenport Ranch. Cost includes transportation (full size SUVs), all meals and snacks, entrance fees, and one night at the Mayan Dude Ranch (double occupancy). The Paleontological Society will sponsor two students to attend this trip.

FT25CN425. Warren Hamilton Field Trip: The West Texas Nexus: Orogeny, Magmatism, K-Pg Boundary, Vertebrate Biostratigraphy, and Chihuahuan Desert Geohydrology. Tue–Sat. 14-18 Oct, 2 p.m. (first day)–5:30 p.m. (last day). US$715. CEUs4.
Endorsed by GSA’s Planetary Geology, Mineralogy, Geochemistry, Petrology, and Volcanology, Structural Geology and Tectonics, Geochronology Divisions
Location: Begins in Midland, Texas, USA
Led by: Jesse Kelsch, Thomas Shiller, Patricia W. Dickerson, Joe Satterfield, Kevin Urbanczyk, Elizabeth Koeman-Shields
Big Bend structures, strata and waters record >500 Ma of Earth history. On this trip we'll visit:Paleozoic strata of the Marathon Basin; the Marathon fold-thrust belt recording Pangea assembly; Early Cretaceous marine platform carbonates; Late Cretaceous megafauna (Alamosaurus & Quetzalcoatlus); the K-Pg boundary; Laramide contractional structures of the Terlingua Uplift and the Sierra del Carmen; some of the 48-18 Ma Trans-Pecos magmatic province, including calderas, lavas, ignimbrites, pluton-associated mercury mineralization, and the Solitario lacco-caldera; Rio Grande rift structures with exposed kinematic history; and the Rio Grande/ Rio Bravo, plus springs from cross-border aquifers. Cost includes transportation (full size SUVs), Riata Inn in Marfa for 10/14 (double occupancy), Chisos Mining Co in Terlingua for 10/15-16 (double occupancy), Marathon Motel in Marathon for 10/17 (double occupancy), meals, snacks, and water. Students can apply for the Warren Hamilton Fund to defer the cost of the trip.

FT25CN426. Highlights of the Hill Country: A Trip Through the Llano Uplift. Thu 23. Oct. 7a.m.–8 p.m. US$85 for students. US$110 for professionals. CEUs 0.8.
Led by: Zachariah Fleming, Michael T. Read, Liane Stevens
This one-day field trip will explore highlights of central Texas and Hill Country geology in and around the Llano uplift. The Llano uplift contains complexly deformed Grenville- aged metavolcanic and metasedimentary rocks that are intruded by syn- and post- tectonic granites. This Mesoproterozoic rock is overlain by Cambrian and younger sedimentary rocks along the flanks of the uplift. Join the trip and we will explore the igneous and metamorphic rocks of Enchanted Rock, a spectacular example of an exfoliation dome, and an excellent location to explore the rocks formed by the continent- continent collision during and following the Grenville orogeny. We will visit an outcrop of the uniquely Texan rock llanite, as well as beautiful exposures of the Cambrian Hickory Sandstone, which nonconformably overlies crystalline basement. Outcrops on this trip range are all accessible either along the roadside or via a short hike. An optional longer hike at Enchanted rock will be offered. Cost includes transportation, lunch, snacks and water. We will stop for dinner in town before heading back to San Antonio.

FT25CN427. Bracken Cave Bat Flight. Mon. 20. Oct. 5:30–9 p.m. US$65. CEUs 0.35. 
Led by: Fran Hutchens and Geary Schindel. 
Bracken Bat Cave is located near Garden Ridge, Texas, about a 45-minute ride from downtown San Antonio. Bracken Cave is the summer home of more than 15 million Mexican free-tailed bats, making it the world’s largest bat colony and one of the largest concentrations of mammals on earth. The emergence of these millions of bats, as they spiral out of the cave at dusk for their nightly insect hut, is an unforgettable sight. During October, the bat flight is more limited but will last too long after dark. The cave is formed in the Edwards Limestone, also home to the Edwards Aquifer. The cave has been featured in nature documentaries by National Geographic and BBC as well as many others. This visit will include a short talk on the natural history of bats, their use of the cave, and threats to these important consumers of insects. This field trip does not enter the cave as it is full of bats and bat guano. Cost includes transportation, snacks, water, and program fee.