Calendar
AGS HOLIDAY SEASON PARTY
All Members are invited to the Berrys’
5000 Beverly Hills Drive 78731
Saturday, December 8th at 5.00 pm
RSVP 512-452-8068 by 5TH Dec. please
William Ambrose, Iulia Olariu, Jinyu Zhang (BEG)
and
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 jlbassoc@gmail.com; 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.
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.
Biography
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.
Leaders: Pete Rose, Chock Woodruff, and Jeff Paine
Stops include:
- 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 charlotte.sullivan@pnnl.gov
Photograph from Hill and Vaughn, 1895
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
ABSTRACT
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.
Bio:
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.
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.
Biography:
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.
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/
Full house of AGS members attended the annual ethics meeting by Dr. Prentice.
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.
Biography:
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.
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.
References:
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
Biography
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 &
INTRAPLATE DEFORMATION
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.
COLLABORATIONS
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.
Formal Education
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:
Bureau of Economic Geology- PRC Campus
10100 Burnet Road
ROC, Building 196
Austin, Texas 78758
512-471-0302
Registration link: http://www.cvent.com/events/fgim-2018-austin-meeting/event-summary-8c11fce15f3442c5bd58d944d38b89ca.aspx
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):
Undergrads:
Early Career Grads:
Late Career Masters:
Late Career Ph.D.:
A few pictures from AGS Poster Sessions of the past:
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.
Biography
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.
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.
Biography
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.
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.
Biography
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.
