Neogene Evolution of Central Texas Landscape after Balcones Faulting
Dr. Peter R. Rose
The Edwards Plateau and the Balcones Fault Zone (BFZ) dominate the geology and physiography of Central Texas. The Edwards Plateau was formed during Early Miocene time by uplift of the area west and north of the arcuate BFZ. The Albian Edwards Group was a continuous sheet of resistant shallow-shelf carbonate strata that covered all of central Texas: the Edwards Plateau, BFZ, and subsurface of the Central Texas Platform. At the time of first Balcones faulting, the Edwards was widely exposed west and north of the BFZ. Regional headward erosion and dissolution following Balcones faulting progressively stripped away Edwards strata, leaving steep, ragged bluffs that delineated the boundaries of the Edwards Plateau. Just as geological maps outline the Edwards Plateau today, a reconstruction of past Edwards Limestone outcrop locations records the stages of westward and northern erosional retreat through Miocene, Pliocene, Pleistocene and Holocene times.
This integrated geologic/geomorphic/hydrologic account is based upon three different categories of diagrams, prepared specifically for this paper:
- A map showing the 26 drainage basins of central Texas;
- Stream profiles of 12 rivers sourced from the Edwards Plateau Aquifer, in context with adjacent geologic boundaries of top (tKed) and base (bKed) of the Edwards Group, and base (bK) of Cretaceous formations within the map area;
- Seven paleogeographic maps of the Edwards Plateau/BFZ area from onset of Balcones faulting (21 mya) to the present time, showing the location of the Edwards Plateau and the courses of all main streams, in 3.5 my stages.
The sequential evolution of the Central Texas landscape is integrated with independent evidence from five related geological processes and events to generate a holistic account of Edwards Plateau and BFZ history since early Miocene time:
- Incised meanders of Edwards Plateau rivers and streams, inboard and peripheral to the BFZ, were probably inherited from early Paleocene conditions, then greatly amplified by Balcones-related uplift.
- High porosity and permeability of Edwards strata in the central sector of the BFZ and Edwards Underground Aquifer is related to a) a longer period of increased stream gradients and stream piracy in that sector; b) a wider BFZ with greatest vertical displacement; and c) the presence of a major discharge point at the lowest elevation in the trend, at San Marcos Springs.
- Between 14 and 10.5 mya, the Colorado River formed its Great Bend, when it shifted its course about 35 miles north and east, after eroding through Cretaceous strata, downward onto hard, northeast-dipping Paleozoic beds. This shift also generated the marked asymmetry of the Colorado drainage basin, with short tributaries on the east, and long straight tributaries on the west.
- Multiple levels of horizontal cave development (youngest downward) in the western Edwards Plateau suggest that the thickness of the Edwards Plateau aquifer was greatest immediately following Balcones faulting, and declined afterward in stages as erosion reduced the area of surface recharge, and increased outflows.
- The post-Balcones Medina Arch induced concave-upward stream profiles in streams originating around its apex: Pedernales, Blanco, Guadalupe, Medina, Frio, and East Nueces Rivers.
Dr. Pete Rose (Ph. D., Geology, University of Texas, Austin) has been a professional geologist for 59 years, specializing in Carbonate Stratigraphy, Petroleum Geology, E&P Risk Analysis, and Mineral Economics. Before going on his own in 1980 as an independent prospector and consultant, he worked for Shell Oil Company, the United States Geological Survey, and Energy Reserves Group, Inc, a small-cap Independent.
After 10 years as an internationally-recognized authority on economic risking of exploration drilling ventures, he founded Rose & Associates, LLP, in 1998. His 2001 book, Risk Analysis and Management of Petroleum Exploration Ventures, now in its 7th printing, is considered by many as the “Bible” on that topic, and has been translated into Chinese, Japanese, and Russian. Pete retired in 2005; Rose and Associates LLP continues as the global standard among consulting companies in that field, providing instruction, software and consulting services on an international scale.
Pete wrote the definitive geological monograph on the Edwards Limestone of Texas (Rose, 1972), and has continued related investigations to the present time -- this will be his 10th published paper on various aspects of the Edwards Plateau area. He has authored or co-authored more than 80 published articles on an extremely wide variety of geological topics. He was a Fellow of the Geological Society of America, the American Association for the Advancement of Science, and Geological Society of London.
In 2005 he was the 89th President of the American Association of Petroleum Geologists, In 2006-07 he was deeply involved in successful efforts to encourage the U. S. Securities and Exchange Commission to modernize its rules governing estimation and disclosure of oil and gas reserves, thus facilitating the investment component of the “shale revolution” in the U. S. Pete ws President of the Austin geological Society in 2012/13.
In 2013, the Geological Society of London awarded Peter R. Rose its prestigious Petroleum Group Medal for lifetime contributions to Petroleum Geology, the first American to be so recognized, and in 2014 the American Association of Petroleum Geologists honored him with its Halbouty Outstanding Leadership Award.
Geology at the Crossroads - Big Bend Ranch State Park Presidio and Brewster Counties, West Texas
Pre- and Post-trip Lodging information:
February 24th (night before departure) and again on February 27th (return to Alpine) participants will need to arrange their own accommodation.
The Quarter Circle 7 Hotel has agreed to block 15 double occupancy (queen beds) rooms. The reduced rate for participants of the AGS Field Trip is $120.60 before taxes, $60.30 per person. If not doubling up please do not request the blocked rooms. Reservations can be made by calling the Quarter Circle 7 Hotel directly at (432) 837 - 1100 and requesting the Austin Geological Society rate. The Hotel Manager's name is Ms. Rebecca Pape.
This location will be the starting and ending points for the trip and all field trip participants will need to assemble there at 7:30 on Monday, February 25th, for prompt departure to Big Bend Ranch State Park. The hotel is located on the West side of town. I have also arranged for monitored parking for all personal vehicles to be left there during the trip. (Hopefully people will be carpooling where possible.) No personnel vehicles will accompany the trip.
Core Workshop (Dec 5): Depositional Systems and Architectural Variability of the Wilcox Group in Texas
William Ambrose, Iulia Olariu, Jinyu Zhang (BEG)
Cornel Olariu, Ronald Steel, Department of Geosciences
Wednesday, December 5th, 2018, 9:00 a.m. - 3:00 p.m.
Location: Core Research Center at J. J. Pickle Research Campus, 10100 Burnet Road Building 131; Austin, Texas 78758; (512) 475-9561
Presented by: The University of Texas at Austin, Bureau of Economic Geology, State of Texas Advanced Oil and Gas Resource Recovery (STARR) Program and the Department of Geosciences
Attendance limited to 40 participants (no registration fee) (Includes morning refreshments and lunch plus presentations on CD and handouts)
To register please contact: John Berry firstname.lastname@example.org; sign up sheets will be at the next AGS meeting
This all-day workshop is an in-depth study of Wilcox Group stratigraphy and depositional systems in Texas based on detailed analysis of more than 1000 well logs and about 900 km2 of 3D seismic data. Attendees will receive a hands-on view of 5 key cores with an extensive review of depositional environments – fluvial, deltaic (wave, tidal and fluvial processes) and upper slope facies. Core descriptions, cross sections and lithofacies maps document temporal and spatial variations in shoreline processes from wave-modified and tide-influenced to wave-dominated deltas and indicate that significant volumes of sandstone were trapped on the outer shelf by contemporaneous growth faults. However, at times the Wilcox shelf margin prograded through mud accretion. Mud-rich shelf to slope transitions documented from cores and seismic data show that significant basin margin progradation can occur in the absence of coarse-grained sediment.
AGS Meeting (December 3): Tectonic History and Metallogeny of Mexico with Focus on Epithermal Deposits of Copper Canyon, Chihuahua
Tectonic History and Metallogeny of Mexico with Focus on Epithermal Deposits of Copper Canyon, Chihuahua
Mexico has a young geologic history, the oldest basement (Grenvillian) near the Gulf of Mexico has been rapidly accreted along the western margin since Mesozoic time. The accreted island arcs and the related subduction, magmatism, and tectonism created an ideal regime for the emplacement of world-class metals deposits.
Mexico has about 7 Metallogenic provinces, wherein the different metal deposits share chemical and structural characteristics. The world’s largest primary silver mine in Fresnillo is at the heart of the Altiplano Silver Province. Running along the western half of Mexico for nearly 1,300 kilometers, exists the largest tertiary volcanic province in the world. More than 250 calderas have been identified in the province that is characterized by a 1,000+m thick rhyolite series which overlies intermediate volcanics. Rapid extensional opening of the Gulf of California (only 8 Ma) served to dissect this terrain into extreme canyons (called barrancas).
In southwest Chihuahua State, there is an extensional juncture that created a “super barranca” which is known as the Cuenca de Oro (CDO), due to the occurrence of gold and silver along its margins. This region is federally known as Copper Canyon (CC) and it rivals the Grand Canyon (GC). The CC is much steeper than the GC and vegetation ranges from pine trees on the high plateau to tropical brush in the valleys, often more than a kilometer below.
El Sauzal, along the northern margin of the CDO, was the largest gold mine in Mexico when constructed in 1998 and was successfully decommissioned in 2015 after producing more than 2 million ounces gold. Batopilas, 20 km east of Sauzal, was discovered by the Spanish in 1632 and has produced more than 250 million ounces silver.
Several projects along the southern margin of the CDO are in early exploration stages. The Cerro Cascaron Project is being drilled by Harvest Gold currently. The Don Chano Project is located 40 km South of El Sauzal & Batopilas, the land position consists of a federal mineral claim, covering 1,413 hectares (3,492 acres) in the Municipality and Ejido of Morelos, Chihuahua.
Mineoro has collected approximately 600 measured-width bedrock samples over the Don Chano Project. High-Grade vein targets and large disseminated bodies of precious metal mineralization have been identified; maximum Gold value of 167 ppm Au w/ 132 ppm Ag encountered at Pacheco; maximum Silver value of 2,130 ppm Ag w/ 18.4 ppm Au sampled at Guadalupe. Visible gold has been confirmed from 2 locations (600m of strike) along the Tres Mujeres Vein Swarm.
Mike started performing geologic work in Mexico about 12 years ago. As an economic geologist he has primarily focused on the early stage exploration of metallic and hydrocarbon deposits. He has operated as a consultant for numerous public and private mineral exploration companies in Mexico and the western USA. Also served as a Geologist, Petrophysicist, and Database Administrator for Oil & Gas E&P Companies operating in the Midland and Anadarko Basins of Texas and Oklahoma.
Born and raised in Houston, TX he caught the “gold bug” while completing his BS at Sam Houston State University in Huntsville, TX. West Texas was calling and his passion for mineral specimens and hard-rock geology were cultivated at the University of Texas at El Paso, where he focused on Economic Geology under the tutelage of Dr. Kenneth Clark and Dr. Philip Goodell.
His MS thesis presented a geologic traverse from Upper Volcanic Series (Bolivar Mine, DiaBras) through Lower Volcanic Series (El Sauzal, successfully decommissioned by Goldcorp in 2015) and into Batholith (Choix, Sinaloa). The Cuenca de Oro (Basin of Gold) is an extensional basin with numerous precious metal deposits exposed along the periphery, this study provided context for the Western half of the CDO.
Networking in the mining industry led to securing funding for a Doctoral Study on a historic gold mining district that was being re-evaluated and drilled. A project-specific deposit model was created for the district from the integration of: field mapping (stratigraphy, structure, alteration, and quartz textures), geochemistry, fluid inclusions, stable isotopes, and age dating. The High Grade District in Northeast California was drilled as the “Golden Ridge Project” and highlights of the 3,500m drill program include a 5' high grade (120 ppm Au) zone and a 30' interval grading 25 ppm Au.
MineOro Explorations is an operating entity that provides: mapping (geology, alteration, under-ground), geochemistry (prospecting/grid), technical reports, due diligence reviews, native relations, permitting, drilling, 3D modeling, and project management services. We have successfully operated in some of the rougher locales, where native engagement and relationships are paramount to any advancement. Mike uses a strong network of contacts and actively explores gambusino leads. Mineoro has also operated with a prospect generator business model, in which mineral projects are vended to explorers that will fund drilling and development. The Chloride Gold Project in NW Arizona has been vended and drilling should commence in short order.
A notable current work is the boot-strapped discovery of the Don Chano Precious Metal Prospect in SW Chihuahua (along the southeastern rim of the Cuenca de Oro). More than 5 bonanza grade structures have been defined by bedrock sampling within the 4 x 1 km footprint. This stratiform deposit has never been drilled and nearly 600 measured width chip samples show strong precious metal activity across the footprint. The project is drill-ready and shares numerous characteristics with other world-class deposits.
Dec. 1, 2018: AGS Field Trip: "In the Footsteps of R. T. Hill--Geologic Excursions in Honor of Edward W. Collins"
"In the Footsteps of R. T. Hill-
-Geologic Excursions in Honor of Edward W. Collins"
Saturday, December 1st 9am - 3pm
Leaders: Pete Rose, Chock Woodruff, and Jeff Paine
- A reexamination of R.T. Hill’s type section(s) of the Edwards Limestone (worked up by Pete Rose)
- An examination of slope failure in the Edwards along the Barton Creek Greenbelt (by Chock Woodruff)
-A geophysical investigation of the interface between Q alluvial terraces and the underlying Glen Rose Limestone (by Jeff Paine)
Sign up with Charlotte Sullivan after the meeting: Or email email@example.com
AGS Meeting (November 5): Reconstruction of Holocene coupling between the South America Monsoon System and local moisture variability from speleothem δ18O and 87Sr/86Sr records
Reconstruction of Holocene coupling between the South America Monsoon System and local moisture variability from speleothem δ18O and 87Sr/86Sr records
Dr. Corinne Wong
Brittany M. Ward, Corinne I. Wong, Valdir F. Novello, David McGee, Roberto V. Santos, Xianfeng Wang, Lawrence R. Edwards, Lucas C.R. Silva, Hai Cheng
Investigating past variability in South American hydroclimate is pertinent to understanding how hydroclimate might respond to global climate change. δ18O records from South America provide insight into past variability of the South American Monsoon System (SAMS). Precipitation δ18O values, however, can be decoupled from local moisture conditions at a given site and, thereby, limit ability to reconstruct local moisture conditions. In this study, we investigate the coherence of Holocene δ18O records from across tropical and subtropical South America using a principal components analysis and assess the co-variability of reconstructed SAMS variability with local moisture conditions reconstructed from speleothem 87Sr/86Sr values. The main mode of variability across Holocene δ18O records (PC1) closely tracks changes in austral summertime insolation, consistent with existing work. Sites towards the periphery of the continent are heavily weighted on PC1, whereas interior sites as not. Further δ18O variability at interior sites bear little similarity to each other and implicate controls, beyond monsoon intensity, on these δ18O records. Further, we develop speleothem 87Sr/86Sr records spanning the Holocene from Tamboril Cave (Brazilian Highlands), Paraíso Cave (eastern Amazon Basin), Jaraguá Cave (Mato Grosso do Sol Plateau), and Botuverá Cave (Atlantic coastal plain) to investigate coupling between reconstructed monsoon variability (reflected by PC1) and local moisture conditions (interpreted from 87Sr/86Sr records). Speleothem 87Sr/86Sr variability is interpreted as a proxy of local moisture conditions, reflecting the degree of water-rock interaction with the cave host rock as driven by variations in water residence time. Speleothem 87Sr/86Sr records from all the sites, except Botuverá cave, do not co-vary with PC1, suggesting that local moisture conditions do not necessary follow variations in monsoon intensity at these interior sites. These speleothem 87Sr/86Sr records, however, generally suggest dry mid-Holocene conditions relative to the early- and late-Holocene, consistent with interpretations of other paleo-moisture records in the region. These results highlight that controls, in addition to SAMS variability, might influence δ18O variability as well as local moisture conditions at interior sites, and stress the need for δ18O-independent reconstructions of moisture conditions.
Dr. Corinne Wong is an environmental isotope geochemist who studies modern cave environments to understand how past climate can be interpreted from speleothem cave deposits and reconstructs past hydroclimate from speleothem isotopic and geochemical variability in the western United States and the region of the South American Monsoon System. Corinne was an Environmental Protection Agency STAR Graduate Fellow at The University of Texas at Austin, a University of California Chancellor’s Postdoctoral Fellow in Davis, California, an Assistant Professor at Boston College, and Research Associate at The University of Texas at Austin.
AGS Meeting (October 1): Advanced Formation Evaluation of Organic-Rich Mudrocks, Honoring Rock Fabric and Geochemistry
Advanced Formation Evaluation of Organic-Rich Mudrocks, Honoring Rock Fabric and Geochemistry
Dr. Zoya Heidari
Complex rock fabric, composition, pore structure, and geochemistry make formation evaluation of unconventional resources extremely challenging. The conventional rock physics models and formation evaluation methods often do not quantitatively take into account the aforementioned complexities in rock properties, which lead to unreliable estimates of reserves, formation properties, and evaluation of hydrocarbon recovery. For instance, conventional well-log interpretation techniques often overestimate water saturation in organic-rich mudrocks, which is equivalent to significant underestimation of hydrocarbon reserves. Other examples include the unresolved mysteries about unexpected water production as well as challenging and inconsistent rock classification efforts.
In this presentation, the impacts of rock fabric, composition, pore structure, and geochemistry on formation evaluation and rock properties such as wettability and mechanical/electrical properties of organic-rich muchrocks will be discussed. Outcomes of recent experimental and computational research developments as well as field applications will be presented to demonstrate that formation evaluation efforts for assessment of reserves and mechanical properties as well as rock classification can be enhanced by honoring realistic and quantitative rock fabric and geochemistry. Further impacts of these research developments include improved description of multi-phase fluid transport in spatially complex reservoirs with the intent to enhance production and recovery factors.
Zoya Heidari is an Associate Professor in the Hildebrand Department of Petroleum and Geosystems Engineering at The University of Texas at Austin. Before joining The University of Texas at Austin, she was an Assistant Professor at Texas A&M University in College Station and the Chevron Corporation faculty fellow in Petroleum Engineering from September 2011 to August 2015. Zoya was the founder and the director of the Texas A&M Joint Industry Research Program on “Multi-Scale Formation Evaluation of Unconventional and Carbonate Reservoirs” from 2012 to 2015. She has been the founder and the director of the University of Texas at Austin Industrial Affiliates Research Program on “Multi-Scale Rock Physics” since 2016. She received a Ph.D. (2011) in Petroleum Engineering from The University of Texas at Austin. Zoya is one of the recipients of the 2017 SPE (Society of Petroleum Engineers) Cedric K. Ferguson Medal, the 2016 SPE regional Formation Evaluation award, the 2015 SPE Innovative Teaching Award, the 2014 TEES (Texas A&M Engineering Experiment Station) Select Young Faculty Fellows award from the College of Engineering at Texas A&M University, and the 2012 SPE Petroleum Engineering Junior Faculty Research Initiation Award. She is the holder of Anadarko Petroleum Corporation Centennial Fellowship #1 in Petroleum Engineering at UT Austin since 2016. Zoya has served as the Vice President of Education for the Society of Petrophysicists and Well Log Analysts (SPWLA) from 2016 to 2018. Her research interests include Petrophysics, Rock Physics, Borehole Geophysics, Formation Evaluation, Integrated Reservoir Characterization of Carbonates and Unconventional Resources, and Completion Petrophysics.
The Importance (and Difficulty) of Being Earnest
By Dr. Robert Prentice
Summary: "Everyone wishes to be ethical, thinks of themselves as ethical, and wants others to think of them as being ethical. However, being as ethical as we wish to be is more difficult than most of us realize."
Bio: Robert Prentice has taught law and ethics at the Texas McCombs School of Business for 38 years. He is faculty director of Ethics Unwrapped, a free video series and educational program available for all to use: https://ethicsunwrapped.utexas.edu/
Diamond Exploration in Kalimantan, Indonesia
Anaconda Minerals performed a heavy mineral diamond exploration program in the jungles of Indonesia during the mid-1980’s. Alluvial diamonds were known from the area and we were searching for the primary source of these diamonds. This photo log of the exploration shows the initial evaluation visit through the establishment of a “base camp” and use of various exploration methods. Many interactions with the native population are photo documented. One story tells of an emergency helicopter landing in a village of “headhunters”. Ultimately, the diamonds were traced from the alluvial terraces back to various older deposits. Some intrusives were tested, but all proved barren of diamonds. Abundant gold recovered led to the prospecting license being sold to an Australian Gold Company.
Dennis was born in Philadelphia, PA and received a B.S. in Geology from Penn State University and a M.S. from Arizona State University. He worked in diamond exploration with Anaconda /Arco both domestically and in the jungles of Indonesia in the early 1980’s. Dennis continued his interests in diamond exploration in Arkansas during the late 1980’s when he was appointed as a technical advisor to the Arkansas State Parks commission on commercial mining at the “Crater of Diamonds” State Park. In 1993, he designed a regional diamond exploration program in Labrador, Canada which resulted in the discovery of the Voisey’s Bay Ni-Cu-Co deposit valued at over $100 billion. Early in 1995, Dennis opened the Diamond Fields office in St John’s, Newfoundland to oversee the exploration drilling and initiate the baseline studies for the project’s Environmental Impact Studies (EIS). In 1996, he returned to Arkansas to complete the economic evaluation of the “Crater of Diamonds” State Park. Dennis completed a Ph.D. on the Arkansas diamondiferous lamproites at the University of Texas at Austin in December 2002. From 2004, Dennis taught geology and environmental sciences at Austin Community College. In 2008, he was hired by the University of Texas at Austin to help write the earth sciences curriculum for a discovery-based course for future elementary teachers. He continues to modify and teach this ground-breaking curriculum at UT Austin.
May 7: Ouachita-Marathon Orogenic Belt Yields New Zircon U/Pb Data Revealing Two Episodes of PЄ-Є Rift Magmatism on the Buried S. Laurentian Margin
Ouachita-Marathon Orogenic Belt Yields New Zircon U/Pb Data Revealing Two Episodes of PЄ-Є Rift Magmatism on the Buried S. Laurentian Margin
Patricia Wood Dickerson
American Geosciences Institute & Jackson School of Geosciences
Structures and strata of south-central Laurentia record supercontinent interactions from Grenvillian orogenesis and assembly of Rodinia, to its fragmentation by rifting, to the amalgamation of Pangaea. Much of the critical evidence, however, lies deeply buried beneath Ouachita thrust sheets and younger strata. Late Proterozoic–Cambrian intraplate magmatism occurred along the eastern, western, and northern margins of the Laurentian craton. Whether similar igneous activity occurred prior to the rift-drift transition along the southern margin had remained uncertain. Our emerging zircon U/Pb data from the Marathon fold-thrust belt and the Devils River Uplift reveal that there were indeed Cryogenian (700-780 Ma) and Eocambrian (600-500 Ma) episodes of intraplate magmatism in this region (Hanson et al., 2016).
Deformed as Pangaea was born, the Marathon belt thus provides new insight into the last days of Rodinia. Debris-flow deposits in Lower-Middle Ordovician sedimentary strata contain cobbles to boulders of unmetamorphosed basalts, trachyandesites and trachytes with intraplate geochemical signatures. A felsic tuff and a bentonite bed from the Marathon Fm. yielded zircons dated at 750-700 Ma (U-Pb, LA-ICPMS), consistent with the average crystallization age of ~706 Ma (U-Pb, SHRIMP, zircon) for trachytic/trachyandesitic clasts from the Ft. Peña Fm. The tuff and bentonite also contained 580- to 520-Ma grains, a suite not represented in the lavas. Detrital zircon analyses are under way to determine the source(s) of the oldest known sediments in the Marathon succession, the Upper Cambrian Dagger Flat Sandstone.
New zircon LA-ICPMS data from Devils River Uplift core samples record both formation and fragmentation of Rodinia (Rodríguez et al., 2017). Zircons from Mesoproterozoic felsic gneisses yield uniform U-Pb crystallization ages of ~1230 +/- 5 Ma [cf. protolith ages of 1238-1232 Ma for Grenvillian granitic orthogneisses in Llano Uplift]. U-Pb data for overlying Lower-Middle Cambrian metasediments/metavolcanics, exhibit pronounced peaks at 700-780 Ma and at 500-600 Ma, as in the Marathon volcanic rocks. In sum, in southern Laurentia two episodes of intraplate magmatism, coeval with those on the eastern margin, contributed to Rodinia rifting and the opening of Iapetus.
Richard E. Hanson, Jonathon M. Roberts, Patricia W. Dickerson, and C. Mark Fanning, 2016, Cryogenian intraplate magmatism along the buried southern Laurentian margin: evidence from volcanic clasts in Ordovician strata in the Marathon uplift, west Texas: Geology, v. 44, no. 7, p. 539-542. DOI:10.1130/G37889.1
Rodríguez, E., Stockli, D. F. and Dickerson, P. W., 2017, New zircon U/Pb geochron-ology from the Devils River Uplift – insights into the Neoproterozoic and early Paleozoic evolution of the southern margin of North America (abs): Geological Society of America, South-Central Section, Paper 1-2. PPT: https://gsa.confex.com/gsa/2017SC/webprogram/Paper289330.html
Patricia Wood Dickerson
Reconstructing the tectonic history of southern Laurentia is Dickerson’s research focus: seeking the diagnostic evidence for Rodinia assembly and fragmentation (West Texas, Argentine Precordillera), Pangaea amalgamation (Marathon/Solitario fold-thrust belt, Ancestral Rocky Mts.), Laramide foreland deformation (Big Bend), and Rio Grande riftng/transform faulting. She draws from those investigations in leading geological and natural history field seminars for students and professional scientists, as well as for Smithsonian groups. Pat has also served on task forces to develop scientific strategies for exploring the Moon and Mars. Research sponsors include NPS and NASA.
RODINIA ASSEMBLY & FRAGMENTATION
Hanson, R. E., Roberts, J. M., Dickerson, P. W., and Fanning, C. M., 2016, Cryogenian intraplate magmatism along the buried southern Laurentian margin: Evidence from volcanic clasts in Ordovician strata, Marathon uplift, west Texas: Geology, v. 44, no. 7, p. 539-542. doi:10.1130/G37889.1
Dickerson, P. W., 2012, The circum-Laurentian carbonate bank, the Ouachita-Cuyania Basin, and the prodigal Llanoria landmass, in J. L. Wilson and J. R. Derby, The Great American Carbonate Bank: American Association of Petroleum Geologists, Memoir 98, chapter 38, p. 959-984. PANGAEA AMALGATION &
Dickerson, P. W., 2003, Intraplate mountain building in response to continent-continent collision – the Ancestral Rocky Mountains (North America) and inferences drawn from the Tien Shan (Central Asia): Tectonophysics, v. 365, p. 129-142.
RIO GRANDE RIFT & TRANSFORMS
Dickerson, P. W., 2013, Tascotal Mesa transfer zone – an element of the Border Corridor Transform System, Rio Grande rift of West Texas and adjacent Mexico, in Hudson, M. R., and Grauch, V. J. S., New Perspectives on the Rio Grande rift: From Tectonics to Groundwater: Geological Society of America, Special Paper 494, p. 475-500.
D. F. Stockli, I. W. D. Dalziel, E. W. Collins (Jackson School of Geosciences, University of Texas, Austin); R. E. Hanson (Texas Christian University); C. M. Fanning (Australian National University); P. Bauer (New Mexico Bureau of Geology); V. J. S. Grauch (U. S. Geological Survey); B. R. Hall (Texas Parks & Wildlife Department). Education & Outreach
SMITHSONIAN INSTITUTION INSTRUCTION on Smithsonian Journeys to Patagonia, Andes (Peru, Chile), Iceland, Galápagos
NASA ASRONAUT FIELD TRAINING
Dickerson, P. W., 2004, Field geophysical training of astronauts in Taos valley – A brief synopsis: New Mexico Geological Society, 54th field conference guidebook, p. 278-281
GRADUATE, UNDERGRADUATE RESEARCH COMMITTEES (UT, TCU, SRSU) TEXTBOOK CONTRIBUTIONS
Dickerson, P. W., 2012, Hotspots, rifts, reefs, deltas, and cratonic basins – Views from space, in Roberts, D. and Bally, A. W., editors, Regional Geology and Tectonics: Principles of Geologic Analysis: Elsevier, chapter 9, p. 246-295.
Muehlberger, W. R., and Dickerson, P. W., 2012, Geological methods, in Roberts, D. G. and Bally, A. W., editors, , in Roberts, D. and Bally, A. W., editors, Regional Geology and Tectonics: Principles of Geologic Analysis: Elsevier, chapter 8, p. 217-244.
B.A. – Geology and classical archaeology (UT-Austin, 1970) Ph.D. – Geology/tectonics (UT-Austin, 1995)
The 54th Forum on the Geology of Industrial Minerals (FGIM) annual meeting is being hosted by the Bureau of Economic Geology at the University of Texas at Austin and co-sponsored by the Texas section of the Society for Mining, Metallurgy & Exploration (SME). The conference will be held April 16–20, 2017. Events include presentations, excursions following half-day technical sessions, mixers, and 2 separate full-day field trips.
Technical Sessions include:
- Advancements in industrial mineral technology
- Geology of Industrial minerals
- Transportation, regulation and logistics of industrial minerals
- Mining and processing of industrial minerals
Bureau of Economic Geology- PRC Campus
10100 Burnet Road
ROC, Building 196
Austin, Texas 78758
Conference Excursions and Field Trips Itinerary
Monday April 16th
- 8:00 am to 12:00noon Technical Session Presentations
- 12 noon to 3:00pm Excursion and Tour at Acme Brick Company in Elgin, TX
- 3:00pm to 5:00pm Excursion to Mount Bonnell & Presentation of Austin Area Geology
- 6:00pm-8:30pm Social Mixer at the Dogwood at the Domain in north Austin, within walking distance of the Hotel
Tuesday April 17th
- 8:00 am to 12:00noon Technical Session Presentations
- 12:00 to 1:00pm lunch
- 1:00pm to 5:00pm Technical Session Presentations
Wednesday, April; 18th
- 8:00 am to 12:00noon Technical Session Presentations
- 12 noon to 3:00pm Excursion and operations tour of Old Castle (formerly Capitol Aggregates Inc.) dolomitic limestone aggregate quarry in Marble Falls, TX
- 3:00pm to 5:00pm Excursion to Austin White Lime quarry and Plant in Austin, TX
- 6:00pm-8:30pm Banquet dinner will be at Yard House in north Austin, within walking distance of the Hotel
Thursday April 19th
- 8:00am to 12am Travel to San Antonio and Cemex cement plant operation in New Braunfels, TX
- 12:00 to 1:00pm Lunch at old cement quarry site, now a Japanese Tea Garden
- 1:00 to 2:00 Alamo quarry market – 1908 cement site; Belknap place oldest existing concrete street in Texas
- 2:00pm to 5:00pm Martin Marietta’s Rio Medina limestone aggregate quarry west of San Antonio, and back to Austin
Friday April 20th
- 8:00am to 11:00am Travel to JM Huber underground limestone mine in Marble Falls, TX
- 11:00 to 12:00noon Coldsprings granite dimension stone quarry in Marble Falls, TX
- 12:00noon to 3:00pm Travel to U.S. silica industrial and frac sand quarry in Voca, TX
- 3:00pm to 5:00pm Travel back to Austin
Guest/Spouse Conference Excursions and Field Trips Itinerary (Suggested timing)
Monday April 16th
- 8:00 am to 11:00am Bullock Museum
- 11:00am to 1:00pm Capitol of Texas walking Tour
- 1:00pm to 4:00pm Blanton Museum
- 6:00pm-8:30pm Social Mixer at the Dogwood at the Domain in north Austin, within walking distance of the Hotel
Tuesday April 17th
- 8:00 am to 12:00noon Travel to Waco, TX and visit the Dinosaur State Park
- 12:00 to 1:00pm Lunch and visit at Magnolia Farms / Silos
- 1:00pm to 3:00pm Options of Waco Mammoth site, Dr. Pepper Museum or Texas Ranger Museum 3:00pm to 5:00pm Travel back to Austin, TX
Wednesday, April; 18th
- 8:00 am to 11:00am Zilker Botanical Garden Tour
- 11:00am to 1:00pm Lunch and Town Lake walking paths
- 1:00pm to 4:00pm Ladybird Johnson Wildflower Center Tour
- 6:00pm-8:30pm Banquet dinner will be at Yard House in north Austin, within walking distance of the Hotel
Thursday April 19th
- 8:00 am to 12:00noon Travel to San Antonio, TX and visit the Witte Museum
- 12:00 to 1:00pm Lunch at old cement quarry site, now a Japanese Tea Garden
- 1:00pm to 3:00pm Visit the Alamo and Riverwalk
- 3:00pm to 5:00pm Travel back to Austin, TX
Friday April 20th
- 8:00 am to 12:00noon Travel to Fredericksburg, TX and visit the Nimitz Museum
- 12:00 to 1:00pm Lunch and local winery tour (tentatively)
- 1:00pm to 3:00pm Visit the Pioneer Museum
- 3:00pm to 5:00pm Travel back to Austin, TX
AGS will host it's annual poster session that will include the category winners from the UT Symposium. Titles and authors listed below (not a comprehensive list):
- Heat Transport in the Streambed of a Large Regulated River - Sebastian Munoz
- Pyroclastic Flows from Mount St. Helens: The Effects of Topography on Flow Behavior and Deposition on the Leeward Slope - Elizabeth Davis
Early Career Grads:
- Constraints on Mantle Dynamics During Jurassic Rifting in the ENAM Area from Seismic and Petrological Modeling of the Oldest Oceanic Crust - Brandon Shuck
- Rheological Properties and Heterogeneities Along the Down-Dip Extent of a Subduction Megathrust: Insights from the Congrey Mountain Schist, Northern California - Carolyn Tewksbury-Christ
Late Career Masters:
- Provenance and Geochronological Insights into late Cretaceous-Paleogene Foreland Basin Developments in the Subandean Zone and Oriente Basin of Ecuador - Evelin Gutierrez
- Missing Well Log Data Interpolation and Semiautomatic Seismic Well Ties Using Data Matching Techniques - Sean Bader
Late Career Ph.D.:
- Length Scales and Types of Heterogeneities Along the Deep Subduction Interface: Insights from an Exhumed Subduction Complex on Syros Island, Greece - Alissa Kotowski
- Testing Models of Orogenic Development in Ecuador: Multi-Proxy Provenance Analysis of the Hinterland Cuenca Basin - Sarah George
- Plagioclase-Dominated Seismic Anisotropy in the Eastern Mojave Lower Crust - Rachel Bernard
A few pictures from AGS Poster Sessions of the past:
Hydrocarbon Accumulations in Igneous and Metamorphic Reservoirs
Mark W. Shuster and Christopher K. Zahm
Bureau of Economic Geology, Jackson School of Geosciences, The University of Texas at Austin
Although oil and gas resources in crystalline reservoirs are not ubiquitous, they may comprise an under-explored resource globally. More than 100 fields with recoverable hydrocarbons in basement or volcanic reservoirs are documented in the literature. This estimate of the number of fields is likely a minimum because information on single well fields and fields in regions such as Russia and parts of the Middle East was not readily accessible. The first reported instance of oil recovered from igneous or metamorphic rocks is from an 1881 test of the Matembo Field in Cuba. Exploration and production of these reservoirs continues today with recent discoveries in the West of Shetlands, offshore U.K.. Of the fields and discoveries with reported volumes, we estimate a total recoverable resource of more than six billion barrel of oil equivalent (boe) from crystalline reservoirs with 13 of these fields each having more than 100 mmboe recoverable.
Trap types include geomorphic-origin “buried hills” and volcanic mounds; structural fault blocks, intrusive sills and laccoliths, “stratigraphic traps” of volcanic deposits and rarely, meteor impact structures. Of these, the “buried hills” are most common with some showing later structural modification. Productive reservoirs are largely dependent on the presence of conductive fractures and fault zones with a lesser component of inter-particle and secondary porosity reflecting diagenetic alteration associated with weathering and fluid flow. Top and lateral seals for most of the accumulations are marine or lacustrine shales with a few cases where impermeable volcanic, evaporite or tight limestone deposits have acted as seals. In some cases the sealing rock directly overlaps the crystalline reservoirs but in many cases, a sedimentary reservoir may overlie the crystalline rocks and in turn be overlain by the ultimate top seal (e.g. shale).
Single well production rates from fractured crystalline reservoirs are field-specific and variable, but maximum oil production rates of individual wells can be high, for example, > 15,000 bopd. Similarly, hydrocarbon column heights vary but many of these fields have hydrocarbon columns exceeding 2000 feet. Many of the fields show pressure connectivity between wells, and these fields show tank-like characteristics which suggests that the fracture systems are connected. Average field porosity is typically 1-2% or less in basement accumulations typified by fractures but in volcanics and where diagenetically enhanced, local porosities can be higher. Field-specific porosities degrade with depth which may indicate a reduction in open fracture density or increased precipitation of cement in fractures. Interestingly, the porosity and permeability profiles for “buried hill” hydrocarbon fields are similar to present day basement aquifers that supply water in many parts of the world (e.g. sub-Saharan Africa, India). These basement aquifers typically show deep weathering profiles as a function of prolonged exposure and surficial or near-surficial weathering. These similarities suggest that the basement oil and gas reservoirs had similar origins.
Key controls on basement oil and gas accumulations include proven hydrocarbon charge with adjacency to mature oil or gas kitchens, timing overlap of hydrocarbon expulsion and tectonic deformation/structural reactivation, and pre-conditioning of ‘basement’ by paleo-weathering.
Mark Shuster (Associate Director: Energy Division) is responsible for managing the Bureau of Economic Geology’s energy-related research. Prior to joining the Bureau in 2016, Mark worked for Shell and affiliates for over 30 years in upstream oil and gas roles around the world includingexploration and appraisal projects in Latin America, Australia, the Middle East/North Africa, Southeast Asia, and North America including the Gulf of Mexico and Alaska. Mark received his Bachelor of Science degree in Geology from the University of the Pacific and his PhD in Geology from the University of Wyoming.
Feb 5: Eogenetic diagenesis of Chinle sandstones, Petrified Forest National Park (Arizona, USA): A record of Late Triassic climate change
Eogenetic diagenesis of Chinle sandstones, Petrified Forest National Park (Arizona, USA): A record of Late Triassic climate change
Steve Dworkin, Baylor University
Fluvially derived tuffaceous Chinle sandstones from Petrified Forest National Park provide a well-preserved Late Triassic archive of climate information. This study focuses on the relationship between climate and meteoric diagenesis as a guide for constraining climate change in western equatorial Pangea during the Late Triassic. Petrographic analysis of Chinle sandstones reveals their wide range of textural attributes, as well as pedogenic and shallow burial diagenetic features that occurred during the Late Triassic. These diverse petrological characteristics are indicative of the evolving Late Triassic climate, when placed into a well-constrained stratigraphic and geochronological framework. The stratigraphic succession is characterized by variations in the abundance of framework grains, detrital matrix, weathering intensity of feldspar and volcanic rock fragments, and the mineralogy of clay cements. Climate records from Chinle paleosol geochemistry indicate a progression from wet to dry conditions. This trend is also reflected in the meteoric diagenetic features of Chinle sandstones. During deposition of the lower Chinle, elevated rainfall promoted the weathering of labile volcanic detritus to kaolinite, whereas feldspars (especially plagioclase) were partially or completely dissolved. In the upper Chinle, a trend towards drier conditions favoured the formation of smectite and less feldspar dissolution resulting in a higher abundance of well-preserved plagioclase grains. Shallow burial meteoric weathering reactions in Chinle sandstones reflect the evolving climate during the Late Triassic.
I did my Master’s at Michigan State University in glacial geology and my Ph.D. at UT Austin under the mentorship of Lynton Land, Earle McBride and Luigi Folk. I have been teaching sedimentary petrology and geochemistry at Baylor University since 1991. My research focuses on terrestrial climate reconstructions and the geochemistry of black shales.
Jan 8: Multiphase pre-Andean deformation guides Cenozoic mountain building in the central Andes, southern Peru
Multiphase pre-Andean deformation guides Cenozoic mountain building in the central Andes, southern Peru
Nicholas D. Perez, Texas A&M
The central Andes are the locus of the highest magnitude shortening and crustal thickening along the Cenozoic Andean margin. In southern Peru, pre-Andean shortening and extension during the Paleozoic and Mesozoic, respectively, guided subsequent deformation. Late Permian shortening is evidenced by folds and reverse faults of variable orientation, potentially reflecting fold interference or changing stress orientation. These folds are covered unconformably by volcanic and non-marine siliciclastic rocks of the Triassic Mitu Formation. Lateral variations of facies, thickness, and fault patterns within the Mitu Formation suggest it is the stratigraphic archive of crustal extension overprinting Permian shortening. Although the magnitude and geodynamic drivers of these deformation phases remain debated, inherited structures from both events were selectively reactivated. During Andean orogenesis, the deformation front jumped from the Western Cordillera to the Eastern Cordillera in the Eocene, and potentially localized near pre-existing Triassic extensional structures. Thin-skinned shortening within the Eastern Cordillera reactivated inherited normal and reverse faults. One key structure is the Ayaviri fault, which defines the eastern Altiplano margin, and preserves growth strata constraining Oligocene fault motion. This structure has been variably interpreted as accommodating reverse or strike-slip offset, a reactivated pre-Andean fault, and as a boundary between suites of different volcanic products potentially reflecting contribution from different lithospheric blocks. Structural and magmatic observations from other segments of the Andean margin support variable influence from inherited structural architecture. These results emphasize how pre-Andean deformation may condition the crust for future deformation, as well as the continued need to characterize the role of inheritance on orogenesis.
Nick’s research focuses on basin analysis and tectonics. His expertise is in non-marine siliciclastic sedimentology/stratigraphy, integration of U-Pb geochronology and provenance techniques, structural mapping and balanced cross-sections, and low-temperature thermochronology. His research topics include basin dynamics and sediment routing during deformation, the role of structural inheritance on subsidence and deformation, and the integration of sedimentology, geochronology, and kinematics.
Nick is developing new research projects in the Peruvian Andes, Ancestral Rocky Mountains, Morocco, and the Cascades. Motivated students are encouraged to contact him if interested in M.S. or Ph.D. tectonics research.
This fall is Dr. Jack Sharp's last semester to teach Hydrogeology at UT, and we would like to celebrate his spectacular career.
Join us December 8 (Friday) at the Hydro Brown Bag seminar at the UT Jackson School of Geosciences and/or the BBQ Reception at the Pierce home to share exciting thoughts and reflections on our experiences with Jack.
Hydro Brown Bag Seminar: Reflections and Roasting of Dr. Sharp
Where: UT campus, JGB room 3.222
When: December 8, 12:00 – 1:00
Where: Pierce home, 5903 Deep Spring Cove, Austin, TX
When: December 8, 4:00 – 9:00 PM
The Global Energy Scene: A Few Things You Might Not Read in the Times
Scott W. Tinker
Over the past few decades, a story of “good” and “bad” energy has evolved: renewable good, fossil and nuclear bad. Schoolkids are taught “facts” about energy that often violate economic and even physical principles. Passionate evangelists, Hollywood actors, activist investors, and even national newspapers present slanted “ideal world” scenarios. As the United States considers its position in energy—from climate and carbon, to poverty and immigration, to renewable energy and reregulation of electricity markets—it is vital to understand the facts, real costs and benefits, and global implications of various policies in order to minimize politics and maximize lasting impact. I’ll review a few global-energy realities that you are unlikely to read in the Times, and pose a few questions whose answers might challenge what you think. As Mark Twain is credited with saying, “It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so.”
Dr. Scott W. Tinker is director of the Bureau of Economic Geology, the State Geologist of Texas, a professor holding the Allday Endowed Chair and acting Associate Dean of Research in the Jackson School of Geosciences at The University of Texas at Austin. Scott is past president of the American Association of Petroleum Geologists, the Association of American State Geologists, the Gulf Coast Association of Geological Societies, and the American Geosciences Institute. Scott is a Halbouty Leadership Medalist, a Boyd Medalist, and a Fellow of the Geological Society of America. He has given over 650 keynote and invited lectures to government, industry, academic, and general audiences, and visited nearly 60 countries. Tinker serves on many private, public, academic, and government boards and advisory councils and co-produced and is featured in the award-winning energy documentary film, Switch, which is on thousands of college campuses and has been seen by over 15 million people. He is working on another film project, Switch ON, focused on energy poverty.
Field trip to Lake Georgetown spillway--Albian Rudist buildup
The fieldtrip participants will meet Saturday, November 18 at 9am at the small parking lot outside the entrance gate to the Corps of Engineers Cedar Breaks Park on the south side of Lake Georgetown. Cost per participant is $10 and can be paid on site. Bring field shoes, hat, sunscreen, and water; we will provide a printed field guide. Rest rooms are available in the park but not at the spillway. We will spend at least three hours on the excellent exposures of Albian rudist buildups in the spillway, but there is more of the Edwards/Comanche Peak section exposed to explore on your own.
Please contact Charlotte Sullivan at: charlotte.sullivan(at)pnnl.gov
Nov. 6: Systems Thinking for Macroeconomic Modeling: Energy, Debt, Dynamics, and Economic “Structure”
Systems Thinking for Macroeconomic Modeling: Energy, Debt, Dynamics, and Economic “Structure”
Carey W. King
Macroeconomic modeling needs to consider a wide range of economic factors (employment, wages, economic output, capital, debt, income distribution) and physical factors (population, rate of energy consumption, capital). Most economic models focus on the former factors much more than the latter. The Long-term models also need to consider dynamics that have the ability to understand how the rate of change in the energy system interacts with the rest of the economy. In this talk, Dr. King discusses data and analysis that provide insight into the long-term (100+ years) changes in size and structure of the world and U.S. economy in the context of the size of the energy system. This topic has implications for modeling a transition to a low-carbon economy, a task for which many mainstream economic models (e.g., general equilibrium models) are ill-equipped.
Dr. Carey W King performs interdisciplinary research related to how energy systems interact within the economy and environment as well as how our policy and social systems can make decisions and tradeoffs among these often competing factors. The past performance of our energy systems is no guarantee of future returns, yet we must understand the development of past energy systems. Carey’s research goals center on rigorous interpretations of the past to determine the most probable future energy pathways.
Carey is Research Scientist at The University of Texas at Austin and Assistant Director at the Energy Institute. He also has appointments with the Center for International Energy and Environmental Policy within the Jackson School of Geosciences and the McCombs School of Business. He has both a B.S. with high honors and Ph.D. in Mechanical Engineering from the University of Texas at Austin. He has published technical articles in the academic journals Environmental Science and Technology, Environmental Research Letters, Nature Geoscience, Energy Policy, Sustainability, and Ecology and Society. He has also written commentary for American Scientist and Earthmagazines as well as major newspapers such as the Dallas Morning News, Houston Chronicle, and Austin American-Statesman. Dr. King has several patents as former Director for Scientific Research of Uni-Pixel Displays, Inc.
Core Workshop: Shelf-to-Basin Architecture, Depositional Systems, and Facies Variability of the Southern Eastern Shelf of the Permian Basin
Presented by The University of Texas at Austin, Bureau of Economic Geology: State of Texas Advanced Oil and Gas Resource Recovery (STARR) Program
Sponsored by the Austin Geological Society
October 24, 2017 9:00 a.m. - 3:00 p.m.
Location: Austin Core Research Center, 10100 Burnet Road, Austin, Texas 78758; (512) 471-1534
Registration: Please contact Sigrid Clift at firstname.lastname@example.org; Limited to 30 participants; Registration fee: $30.00 (Includes morning refreshments and lunch plus presentations on CD and handouts, but not $3 parking fee).
This all-day workshop offers an in-depth overview of shelf, shelf-edge, and slope depositional facies characteristics, stratigraphic variations, and sedimentation trends of the Missourian Canyon Group and Virgilian–Wolfcampian Cisco Group across the southern Eastern Shelf and the adjacent Midland Basin. Regional depositional features of equivalent strata of the northern half of the Eastern Shelf are well documented in the works of Frank Brown and others. However, the facies architecture of the southern half of this major petroleum province previously had been only incompletely examined. This study is based on detailed analysis of more than 2,200 well logs and approximately 10 cores within a 19-county area of West Texas. Attendees can get a hands-on view of key cores with a detailed review of depositional environments from source to sink—fluvial incised valley fill, shelf, shelf edge, slope, and slope-to-basin-floor transition. Core descriptions, cross sections, and lithofacies maps document temporal and spatial variations in progradational sediment wedges and indicate that significant volumes of sediments were delivered into the Midland Basin where a thick succession of both siliciclastic and carbonate reservoirs offers numerous opportunities for oil and gas production.
Tucker F. Hentz, William A. Ambrose, Robert W. Baumgardner, and Fritz Palacios
Geology at the Cross Roads: Big Bend Ranch State Park: Geology, Landscape, Culture, History
by Blaine R. Hall, TPWD, Ret.
Big Bend Ranch State Park (BBRSP), is the largest of the Texas State Parks covering an area of over 300,000 acres (~1200 square kilometers). The scenery is magnificent and the landscape varies from river lowlands, through deep canyons, across high plateaus, and up steep mountains. Ultimately all of this is controlled by the character and variety of the underlying geology and the processes that created it over millions of years.
But why a Crossroads of Geology?
Because, the park’s southern boundary follows the Rio Grande from about 10 miles below Presidio through a series of Basin and Range grabens for some 40 miles down-river to Lajitas at the northwest corner of Big Bend National Park. Extensive Cenozoic-age volcanics and intrusives make up the Bofecillos Mountains in the central part of the Park, while the Solitario Dome covers the northeastern corner where early Cretaceous-age limestone mark the flank of the dome and Paleozoic-age chert, sandstone, limestone, novaculite, and shale are exposed in its core. And finally, in southeastern BBRSP early Cretaceous-age shale, marl, and limestone are exposed along the Fresno-Terlingua Monocline.
Furthermore, four of the major orogenic events that mark the development of North America converge in BBRSP. 1) The Ouachita/Marathon foldbelt extends through the Marathon Basin and can be seen in the interior of the Solitario Dome, where exceptional exposures of highly deformed Siluro-Devonian Caballos Novaculite occur. 2) The Laramide foldbelt is also represented in the Park, particularly where the lower Cretaceous Santa Elena, Del Rio, and Buda Formations are asymmetrically folded along the Fresno-Terlingua monocline. 3) Undoubtedly, the most dramatic geological event represented in the Park is the mid-Cenozoic volcanism that built up the Bofecillos Mountains as part of the very extensive Trans-Pecos volcanic province. 4) And finally, along the south edge of BBRSP, the route of the Rio Grande follows Basin and Range age sediment-filled grabens, marked by long, continuous normal to oblique slip faults exposed along very prominent fault scarps.
And Not the Least, the geology and climate have determined the character of the landscape, which in turn greatly influenced the cultural development of the area, and the cultural development through time determines the history of the region.
So, come on out to Big Bend Ranch State Park and watch for the evidence of all four events. Revive your appreciation for the geological enormity of time and scale and the resulting variety of landscape and scenic beauty, both natural and historical, here at the Crossroads.
Blaine Hall joined Texas Parks and Wildlife in 2010 as an Interpretive Ranger at Big Bend Ranch State Park where he used a hands-on approach in explaining the natural and cultural history of the park. In particular, he helped visitors understand the geology of the park, how the geology controls the development of the park’s landscape, and how the landscape has affected the cultural and historical development of the park. He was uniquely suited for this position because he was able to utilize his wide ranging industry experience, substantial teaching experience, and strong academic background. Blaine completed his B.S. in Geology at UT El Paso, received his M.Sc. in Geological Oceanography from Dalhousie University, and carried out research in marine geology and geophysics while at Lamont-Doherty Earth Observatory of Columbia University. His industry experience began with Superior Oil in minerals exploration for Proterozoic placer gold (South African type) and Kimberlites (Diamonds) in the Rockies, Canada, Kansas, and Arkansas. He then shifted to petroleum, beginning with studies of heavy oil reservoirs in California for Mobil Oil and continued with exploration and production programs in southern South America for Mobil while based in Buenos Aires. He went back to Argentina for Parker and Parsley and consequently, Pioneer Natural Resources. After leaving industry, Blaine returned to his native West Texas and spent the next ten years teaching Geology and Mathematics at Sul Ross State University. While at Sul Ross, he was also very active with the Chihuahuan Desert Research Institute where he developed a permanent exhibit on the geology of the surrounding Davis Mountains and presented workshops for teachers and many other youth and continuing education programs.
Since his retirement from TPWD in 2015, Blaine, now residing in Fort Davis, has continued studying the geology of Big Bend Ranch State Park and guiding the work of others there. He is helping direct the thesis research of Master’s students from Sul Ross State University on differing aspects of the Cenozoic volcanism and tectonics in the park, as well as, special projects for undergraduate McNair Scholars. Blaine is also actively involved with UT Austin faculty and staff in studies of the lower Paleozoic units now exposed in the core of the Solitario, an uplifted and eroded intrusive dome in the park.
September 15-17, 2017
Cave Without a Name, 325 Kruetzberg Road Boerne, Texas
Join us in the field for a weekend of learning and fun with leading researchers and practitioners from across the nation. More than 30 modules will be offered including:
- Stream Gauging
- Water Level Measurements
- Data Collection
- Drilling Demonstrations
- Tracer Testing
- Karst Feature Evaluation
- Surface & Borehole Geophysical Surveys
- Field Instrument Use
More information can be found here: http://caves.org/grotto/bexargrotto/HydroGeo/
Austin Geological Society Annual Ethics Training for 2017
Presented by Will Boettner, P.G. (AGS President)
All licensed geoscientists in the State of Texas are required to complete annual ethics training as part of their Continuing Professional Development. Given that all or most of the practicing geoscientists in Texas are honorable and dedicated at their profession, the question arises of what exactly are ethics in geoscience practice, what purpose do they truly serve and why are they required.
Making ethical decisions about geoscience serves to protect the public we serve, society in general, and protects the good name of the geoscience profession. Working with a Code of Conduct standardizes expectations and actions of practicing geoscientists in a manner that is dependable and reliable for society at large. Approaches to making ethical decisions can be mapped out and followed to provide reproducible results. In the end, ethical practice and a professional code of conduct serve the interests of society, science and our professional standing.
Note this meeting was rescheduled from August 28, 2017 due to Hurricane Harvey. Our thanks to Will for stepping in to provide an Ethics talk and get the year started.
May 1 AGS Meeting: Mudrocks (shales, mudstones) at the Scale of Grains and Pores: Current Understanding
Mudrocks (shales, mudstones) at the Scale of Grains and Pores: Current Understanding
Dr. Kitty Milliken, Bureau of Economic Geology
The fine-grained sediments and rocks that constitute most of the sedimentary record have received tremendous research attention in the past decade. This talk reviews some of the technologies that have supported these advances and summarizes current knowledge of the diagenetic processes that drive the evolution of bulk rock properties of mud in the subsurface. Electron microbeam instrumentation has been central to improving our understanding of fine-grained materials. In particular, improvements in resolution offered by field-emission electron guns and advances in sample preparation by various ion-milling techniques have allowed researchers to see tiny grains and pores in unprecedented detail. Grain assemblages in mudrocks vary across a very broad compositional range and the beginning compositions in muds have significant implications for the evolution of properties relevant to reservoir quality in mudrocks. It is now clear that the principal diagenetic processes of sandstones and limestones, compaction and cementation, also operate in mudrocks. Research efforts to quantify the roles of compaction and cementation are central in the quest to refine a predictive understanding of the evolution of mudrock properties in the subsurface.
Kitty L. Milliken received a B.A. in geology (1975) from Vanderbilt University and M.A. (1977) and Ph.D. (1985) degrees from the University of Texas at Austin. Currently she is a Senior Research Scientist at the Bureau of Economic Geology in Jackson School of Geosciences. Her research focuses on the diagenesis of siliciclastic sediments and the evolution of rock properties in the subsurface. She has authored and co-authored around 90 peer-reviewed papers, over 100 abstracts, and also digital resources for teaching sandstone and carbonate petrography. She served as Associate Editor of the Journal of Sedimentary Research (1993-2000) and as Co-Editor (2004-2008). In 2006 she toured as a J. Ben Carsey Distinguished Lecturer for the AAPG; she was elected a Fellow of the Geological Society of America (2008). Her current work is focused on the application of electron microbeam imaging and analysis to interpret chemical and mechanical histories of mudrocks (oil and gas shales).
Panel Discussion: "Whatever possessed you to become a geologist?" or"How and why I became a Geoscientist, and what that decision led to."
The theme of the next meeting will be the interview of three distinguished geologists, John Berry, Pat Dickerson, and Ernie Lundelius. The discussion will center around the same topics as were on the member survey that we conducted at the last meeting.
Specifically, we will be asking them about: 1) when they knew they wanted to geologists, 2) what about geology appealed to them, 3) who influenced them the most, 4) what they would have become, if not geologists, and 5) what their best jobs were. We will also be releasing the results of the member survey covering the same questions.
A Scenic Tour of the Subsurface of the Austin Area (Bastrop-Marlin); Milano Fault Zone and Cretaceous to Eocene Stratigraphy
By Thomas E. Ewing, Frontera Exploration Consultants, San Antonio TX 78259
A recent project in support of groundwater modeling in the area east and northeast of Austin has allowed a good look at regional stratigraphy and structure in the eastern capitol area. Noteworthy items include:
- Shelf edges of the Lower and Upper Edwards
- Northeast thickening of the Eagle Ford
- Austin carbonate bank and the Waco Channel
- Enigmatic shelf sandstones
- Milano Fault Zone - en echelon grabens
- Simsboro Sand - Thickens in graben fill indicating fault movement
This talk will be a preliminary overview, a paper on the fault system will be presented at GCAGS in the fall.
Dr. Thomas Ewing is a geoscientist with over 33 years of experience in hydrocarbon exploration and research. He is a Registered Professional Geoscientist in the State of Texas (#1320) and an AAPG/DPA Certified Petroleum Geologist (#4538), and holds certification #1610 from SIPES. He received a B.A. in Geology from the Colorado College (1975), an M.S. in Geochemistry from New Mexico Institute of Mining and Technology (1977), and a Ph.D. in Geological Sciences from the University of British Columbia (1981).
Dr. Ewing was a research geologist for four years at the Texas Bureau of Economic Geology in Austin, working on Gulf Coast geopressured reservoirs, serving as a co-author of the "Atlas of Texas Oil Reservoirs", and compiling the Tectonic Map of Texas. He is now a partner in Yegua Energy Associates, LLC
Tom has published over 75 papers and abstracts. Among other awards, he has twice received the Gulf Coast Section AAPG Levorsen Award (1982 and 1999), and has received the AAPG Distinguished Service Award. He has written articles on Gulf Coast geology and hydrocarbons, the geology and tectonics of Texas, and history and urban geology of the San Antonio area. He wrote the popular guidebook “Landscapes, Water and Man: Geology and Man in the San Antonio Area” published by the South Texas Geological Society in 2008.
In his spare time, he leads field trips in South Texas, and directs a 60-voice German men’s chorus, the San Antonio Liederkranz.
Trip Leaders: Alan Cherepon, Sylvia Pope, and Scott Hiers
Sign up with Charlotte Sullivan ph: 512.809.0656 email: charolotte.sullivan(at)pnnl.gov
Assembly point: Pickle Research Center, 10100 Burnet Road, Austin 78758; Meet bus in visitor parking lot on North side of Burnet Rd entrance.
The next field trip of the AGS is scheduled for 2/25/17 from 7 AM to 5:30 PM in the greater Austin area, and will be a bring-your-own-box-lunch event so as to get the most out of the day. Six springs and seeps will be visited; one in each of the water bearing spring units, from the Glen Rose up through the Quaternary Terrace Deposits. This trip will emphasize that there are small springs and seeps all over Austin if you know where to look. These springs are less studied as compared to Barton or Seider’s Spring. The span of hydrogeology to be covered will compare and identify the reasons why specifying units in the Austin area springs can often be difficult. Some outstanding fossils, faults, scenery, and history will be seen and discussed. WARNING: Some of the sites are difficult to access, will require traversing steep slopes and slippery creek beds, water in the creek beds and getting feet wet. The suggested footwear is waterproof hiking boots or knee high rubber boots. The sites are unique and will be well worth the effort. Come join us for a field trip that promises to be worth your while.
The Rio Grande Delta and its Surroundings: Frontiers of Geoscience and Development
Saturday-Sunday, February 11-12, 2017
Sponsored by the Corpus Christi Geological Society; Leaders:
- Thomas E. EWING, Frontera Exploration Consultants, San Antonio, TX
- Juan L. GONZALEZ, Dept. of Env. Sciences, UT-Rio Grande Valley, Edinburg, TX
Join your colleagues on a two-day exploration of the Rio Grande Delta, a unique delta-shoreline complex at the southern tip of Texas. The Rio Grande delta is one of the major deltas of North America. Over 1,600,000 people live on the Holocene delta plain and its Pleistocene ancestors, yet geologic knowledge is limited.
The delta was formed by the sediment-rich Rio Grande/Rio Bravo during the Altithermal. The river carried huge but irregular flows into a semiarid environment. Eolian activity has extensively modified the delta plain. Human settlement and infrastructure has exploited the delta and its river, such that recovering natural conditions and values is a present challenge. Major historical developments, including Mexican War and Civil War battle sites, will be addressed as well.
Combining available geologic information with global satellite photography gives a balanced view of an important delta. But a lot of work remains to be done! Come help define the problems and the ways we can resolve them. We will visit:
- The South Texas eolian sand sheet and Sal del Rey, an historic salt deposit
- Lagunas, esteros, and distributary channels in the Holocene floodplain
- Clay dunes and the 'hilly delta'; erosion and accretion
- Transgressive shoreline at Boca Chica and South Padre
- Irrigation and drainage features, and preserved battlefields
- Thick Oligocene ash in the upper valley-side bluffs near Rio Grande City
Logistics: Trip departs from Corpus Christi, TX 9am Saturday (place TBA), and returns to Corpus Christi, TX about 6:30 pm Sunday. Bus transportation, hotel (double occupancy), guide materials, breakfast burritos, lunches, and water are provided. You cover: dinner, personal items.
Cost: Estimated at $300, minimum 15 participants. More details to follow.
Contact: If you're coming, please contact the trip leaders:
Thomas Ewing email@example.com
Juan Gonzalez firstname.lastname@example.org
Dawn Bissell email@example.com