OUTCROP
Newsletter of the Rocky Mountain Association of Geologists
OUTCROP
Newsletter
of the Rocky Mountain Association of Geologists
730 17th Street, B1, Denver, CO 80202 • 720-672-9898
The Rocky Mountain Association of Geologists (RMAG) is a nonprofit organization whose purposes are to promote interest in geology and allied sciences and their practical application, to foster scientific research and to encourage fellowship and cooperation among its members. The Outcrop is a monthly publication of the RMAG.
2025 OFFICERS
PRESIDENT
AND BOARD OF DIRECTORS RMAG STAFF
Matthew Bauer matthew.w.bauer.pg@gmail.com
PRESIDENT-ELECT Sandra Labrum slabrum@slb.com
1st VICE PRESIDENT
Nate La Fontaine nlafontaine@sm-energy.com
1st VICE PRESIDENT-ELECT Rachael Czechowskyj sea2stars@gmail.com
2nd VICE PRESIDENT Ali Sloan ali@sloanmail.com
2nd VICE PRESIDENT-ELECT Lisa Wolff lwolff@bayless-cos.com
SECRETARY Drew Scherer latirongeo@gmail.com
TREASURER
Astrid Makowitz astridmakowitz@gmail.com
TREASURER-ELECT
Walter Nelson wnelson@integratedenergyresources.com
COUNSELOR
John Benton jbenton@haitechinc.com
ADVERTISING INFORMATION
Rates and sizes can be found on page 39. Advertising rates apply to either black and white or color ads. Submit color ads in RGB color to be compatible with web format. Borders are recommended for advertisements that comprise less than one half page. Digital files must be PC compatible submitted in png, jpg, tif, pdf or eps formats at a minimum of 300 dpi. If you have any questions, please call the RMAG office at 720-672-9898.
Ad copy, signed contract and payment must be received before advertising insertion. Contact the RMAG office for details.
DEADLINES: Ad submissions are the 1st of every month for the following month’s publication.
The Outcrop is a monthly publication of the Rocky Mountain Association of Geologists
DESIGN/LAYOUT: Nate Silva | n8silva.com
EXECUTIVE DIRECTOR
Bridget Crowther bcrowther@rmag.org
LEAD EDITOR
Danielle Robinson danielle.robinson@dvn.com
CONTRIBUTING EDITORS
Elijah Adeniyi eadeniyi@slb.com
Nate LaFontaine nlafontaine@sm-energy.com
RMAG CODE OF CONDUCT
RMAG promotes, provides, and expects professional behavior in every engagement that members and non-members have with the organization and each other. This includes respectful and inclusive interactions free of harassment, intimidation, and discrimination during both online and in-person events, as well as any content delivered by invited speakers and instructors. Oral, written or electronic communications that contain offensive comments or demeaning images related to race, color, religion, sex, national origin, age, disability, or appearance are not appropriate in any venue or media. RMAG reminds members of the diversity and mission statements found on our website. Please direct any questions to staff@rmag.org
MEMBERS
EVENT ATTENDEES
WEBSITE VISITORS
OUTCROP READERS
EMAIL SUBSCRIBERS
NETWORKING EVENTS
CONTINUING EDUCATION EVENTS
FIELD TRIPS
COMMUNITY CONTACTS IN 2024YOUR SUMMIT SPONSORSHIP DOLLARS SUPPORTED: 1,200 1,200 8,000 8,000 5,000 4,000 23 13 10
October 30, 2024
Geoscience Community:
We sincerely appreciate the support every Summit Sponsor and Event Sponsor provided over the past year. Your contributions are vital to the success of the Rocky Mountain Association of Geologists (RMAG).
In 2024, the RMAG was proud to host a dynamic lineup of events, including the CCS Workshop, which provided an in-depth look at advancements in carbon capture and storage. Members explored the beauty and geological wonders of the Colorado Rockies with ten diverse field trips and shared our passion for geoscience with students across the region through classroom visits and community festivals. Additionally, we fostered connections among members through monthly lunches, coffees, happy hours, and our annual Golf Tournament.
Looking ahead to 2025, we are excited about new opportunities for RMAG. Your sponsorship will help RMAG realize a robust calendar of continuing education opportunities, an exciting season of field trips, high-impact short courses, and a dynamic lineup of luncheon speakers. In April 2025, we look forward to the North American Helium & Hydrogen Conference, building on the success of our 2023 North American Helium Conference. Your sponsorship empowers RMAG members to impact the next generation at outreach events throughout the community and provides invaluable networking opportunities for the geoscience community. Furthermore, your financial support plays a crucial role in our publication efforts, which include the monthly Outcrop newsletter and the quarterly Mountain Geologist journal.
In recognition of your financial commitment to supporting geoscience in the region we recognize our sponsors through in-person signage, advertising on our website, publications, and social media promotions leading up to each event. With a LinkedIn group of almost 3,000 members, we ensure our sponsors are visible to the geoscience community for both virtual and in-person events.
Thank you to our current Summit Sponsors; we look forward to your continued support in 2025. For those considering sponsoring, we encourage you to explore the many benefits included at each sponsorship level and consider how you can promote geoscience in the Rockies. If an annual sponsorship doesn’t suit your company’s needs or if you wish to sponsor a specific event, please inquire about our single-event sponsorship opportunities. Feel free to reach out to our staff with any questions about sponsorship at bcrowther@rmag.org or by phone at 720- 672-9898 ext. 102.
On behalf of the RMAG staff, volunteers, and myself thank you all for your continued support, and we look forward to connecting with you in 2025.
Sincerely,
Matthew Bauer
Bridget Crowther 2025 RMAG President RMAG Executive Director
RMAG 2025 SUMMIT SPONSORSHIP
All sponsor benefits event tickets follow RMAG event registration deadlines. All benefits end 12 months after registration.
RMAG 2024 ANNUAL SUMMIT SPONSOR OPPORTUNITIES
Platinum Sponsor
Gold Sponsor
Silver Sponsor
Summit Sponsorship benefit term is for 12 months! Specify type of payment on signed form, and send logo and advertisements to staff@rmag.org
Company:
Company Representative:
Address:
City: State: Zip Code:
Phone: Email:
Payment Method: Credit Card ACH Check
Credit Card Information:
Select Card: AMEX Mastercard VISA Discover
Name as it appears on Credit Card:
Credit Card #:
Expiration Date:
Signature:
Security Code:
ACH: contact the RMAG office at staff@rmag.org for directions.
Mail Checks payable to RMAG:
Rocky Mountain Association of Geologists (RMAG)
730 17th Street, B1 Denver, CO 80202
RMAG events are subject to change. Cancellation or rescheduling of events does not give the sponsor the right to refund. Summit Sponsors will receive benefits at any new events added into the RMAG schedule.
Thank you for your generous support!
P: (720)672- 9898 staff@rmag.org www.rmag.org
730 17th Street, B1 Denver, CO 80202
RMAG MARCH 2025 BOARD OF DIRECTORS MEETING
By Drew Scherer, Secretary flatirongeo@gmail.com
Spring has sprung here in the Rockies, and the RMAG board met via Zoom on April 23rd to keep the momentum rolling. With nearly a full house (with all but 4 board members in attendance) we covered a lot of ground.
March was on the quieter side for our usual gatherings, coffee, luncheons, and happy hours saw lighter attendance. But while the calendar may have taken a breather, your committees certainly didn’t. The Finance Committee noted that despite a welcome burst of membership renewals, net revenue dipped slightly in March. In light of current stock market jitters, the committee is proactively exploring lower-risk investment strategies to help preserve our solid financial standing.
On the brighter side, the Continuing Education
Committee is firing on all cylinders. Luncheons are booked through May, and speakers are being lined up well into the back half of the year. Even more exciting, they’re hard at work organizing a career fair alongside the RMS-AAPG meeting, complete with career development workshops and networking opportunities for geoscientists at every stage.
The Hydrogen-Helium Conference was a hit! Attendees enjoyed engaging, top-tier content and the event delivered a positive return for the organization, cheers to that.
The Membership Committee is cooking up summer fun, including a family-friendly hiking series and a sand volleyball day to help us all make the most of the warm weather ahead.
Meanwhile, the Publications Committee has The Outcrop scheduled through July and is finalizing a strong spring issue of The Mountain Geologist, which will feature five new articles hot off the press.
The Geoscience Outreach Committee has been busy with events throughout March and is now seeking volunteers for upcoming appearances at Juneteenth (June 15) and Pride (June 28–29). If you’ve got a passion for outreach, or just enjoy sharing rocks with curious minds, this is your moment.
Finally, the On The Rocks Committee is gearing up for an adventurous summer of field trips. First up: Glenwood Springs Cave and Carbonates, and the Dotsero Volcano in May. Dust off those boots!
From publications to public outreach, conferences to career fairs, RMAG is humming with activity. We hope to see you out there soon!
Denver, Colorado ~ April 9-10, 2025
PRESIDENT’S LETTER
By Matthew Bauer
Fellow Members,
I was approached by Dr. Steven Sonnenberg about supporting efforts to instate professional registration of geologist in Colorado, specifically for the adoption of the ASBOG© (National Association of State Boards of Geology) Model Licensure Law and associated Cooperative Reciprocity Agreement as foundation for regulating geologic practice in Colorado. Since the repeal of Colorado Revised Statutes §§ 34-1-201 and 341-202 in 2013 Colorado has not required licensure or registration of geologists. Personally, I find it odd that a state rich in geological resources and history prior to 2013 we utilized other states’ or professional organizations’ registration then repealed it in leaving nothing in its place.
The majority of states in our great nation use the
ASBOG examination to ensure competency and registration provides an avenue to enforce ethical behavior. Since the repeal of Colorado Revised Statutes §§ 34-1201 and 34-1-202 in 2013, there has been a notable gap in public protection and professional accountability in geoscience-related work. The absence of a licensure requirement places Colorado out of alignment with the majority of U.S. states and territories that require licensure for practicing professional geologists. As Colorado experiences rapid growth in industries that depend on sound geological science, this regulatory gap becomes increasingly problematic.
THE NEED FOR LICENSURE IN COLORADO
Colorado’s geological setting makes it a hub for industries that depend on rigorous geoscientific evaluation. These include:
• Carbon Capture, Utilization, and Storage (CCUS): Ensuring the longterm safety of CO₂ sequestration sites requires expert understanding of stratigraphy, structural geology, hydrogeology, and geomechanics.
• Geothermal Energy Development: Accurate subsurface modeling and project risk assessments are critical to economic and sustainable development.
• Hydrogen Energy & Helium Development: As these growing sectors continue to develop there is need for precise effort for exploration, development, and geologic storage.
• Mining and Resource Extraction: Accurate exploration ensures effective and economic domestic supplies of essential inputs to our modern society. The need for domestic supplies of metals including copper and rare earth elements (REEs) is essential to continued green energy and high technology
development. Proper oversight of responsible development mitigates environmental impacts, subsidence risks, and water contamination.
• Infrastructure and Engineering Projects: Geologic hazards such as landslides, swelling soils, radon, and fault zones pose risks to public safety.
• Groundwater Resource Management: Protecting aquifers from overuse and contamination requires skilled hydrogeologic assessment.
• Environmental Remediation and Site Characterization: Qualified professionals are needed to evaluate contamination and guide cleanups.
In each of these areas, the lack of a licensing framework allows unqualified individuals who may have histories of unethical behavior to submit geologic reports that may have significant impacts on public health, safety, and environmental integrity.
The recommendation that Colorado adopts the ASBOG® Model Licensure Law and participate in the ASBOG® Cooperative Agreement for reciprocity would place Colorado in alignment with the majority of U.S. states and territories. This model has been
successfully implemented across dozens of U.S. states and ensures a consistent, fair, and nationally recognized standard for licensure. Requiring PG licensure in Colorado will:
• Protect the public and environment from the risks of unqualified geological work
• Ensure accountability and enforceable standards of ethical practice
• Enhance Colorado’s credibility and competitiveness in geoscience-driven industries
• Allow for reciprocity and mobility of professional geologists across state lines
Taking action to require Colorado’s professional geology licensure framework through the ASBOG® model will supporting responsible resource extraction, development of green technology, and stewardship of our environment.
That said I’d like to hear from you about your thoughts on the benefit and/or cost of a Colorado PG at president@rmag.org.
Stay Curious and be Good to People, -Matthew
GEOLOGIC HYDROGEN POTENTIAL IN THE ROCKY MOUNTAIN REGION
BY JANE S. HEARON, SARAH E. GELMAN, GEOFFREY S.
U.S. Geological Survey, Denver, CO
WHAT IS GEOLOGIC HYDROGEN?
Geologic hydrogen, also known as natural hydrogen, is hydrogen gas that is naturally found below the surface of the Earth. Unlike hydrogen produced through industrial processes, geologic hydrogen is sourced by, and stored in, rocks in the ground, similar to oil and gas resources. Geologic hydrogen is a clean fuel, meaning that when it burns, it only produces water as a byproduct. This makes it an attractive alternative to hydrocarbon-based fuels, which release carbon dioxide when burned. Geologic hydrogen has the potential to be a sustainable and environmentally friendly energy source within the United States and around the world.
The U.S. Geological Survey (USGS) recently published an estimate that global, in-place hydrogen resources could be millions of metric tons (Mt) (Ellis and Gelman, 2024). The authors note that recovery of even a small fraction of that resource could
ELLIS
potentially supply the projected hydrogen needed to reach global net-zero carbon emissions for hundreds of years. Despite this potentially large resource, exploration for geologic hydrogen remains in an early stage and discoveries of high concentrations of subsurface hydrogen are still relatively rare.
HOW DOES IT FORM AND WHERE DOES IT OCCUR?
Geologic hydrogen is formed through natural processes within the Earth. One common mechanism is a reaction between water and certain iron-rich rocks, a process known as serpentinization. Another common mechanism is the process of radiolysis, where the natural radiation of rocks within the Earth breaks down water molecules to produce hydrogen. A third option is the outgassing of deep sources derived in the lower crust or possibly deeper in the Earth’s interior. A fourth mechanism is the metagenesis of organic matter in overmature, organic-rich
mud-gas logging tools do not routinely measure hydrogen. Additionally, hydrogen was commonly used as a carrier gas in laboratory gas analyses, preventing the analysis of natural concentrations. In a world that historically has sought petroleum, discoveries of hydrogen-saturated formation fluids, if recognized at all, were generally considered a failure, and were ultimately abandoned. Therefore, despite the millions of exploratory and production boreholes that have been drilled throughout the United States and globally, the possibility of hydrogen as a new potential fluid target remains.
WHAT IS THE HYDROGEN SYSTEM?
The geologic hydrogen system is analogous to the well-known model for petroleum systems. Both the geologic hydrogen and petroleum models contain the following components that are essential for subsurface accumulations: source, migration pathways, reservoirs, traps, seals, preservation, and timing. Both models assume that migration primarily occurs by buoyancy-driven flow, that reservoir quality is determined by porosity and permeability, and that accumulations are contained within structural and/or stratigraphic traps and seals. However, three key differences exist between the models which are specific to source, preservation, and timing.
The geologic hydrogen model has very different source rocks compared to the petroleum model. In the petroleum model, hydrocarbons are sourced from organic-rich, sedimentary rocks that have been thermally stressed to produce oil and/or gas during burial. In the geologic hydrogen model, hydrogen can be sourced by multiple processes including: serpentinization of ultramafic, iron-rich rocks; the natural radiolysis of water; degassing of deep, mantle sources; and metagenesis of over-mature, organic-rich sediments. The serpentinization process occurs when ultramafic, iron-rich rocks containing minerals such as olivine interact with water and produce hydrogen. The generalized serpentinization reaction can be written as follows:
3Fe2SiO4 + 2H2O Fe3O4 + 3SiO2 +2H2
Radiolysis of water occurs when water dissociates into its elements creating molecular hydrogen.
FIGURE 1: Reaction pathways associated with water radiolysis leading to the primary products including hydrogen (H2) (after Lousada et al., 2016).
This process occurs when water interacts with the natural radioactive decay of elements such as uranium, potassium, and thorium, which are commonly found in old, Proterozoic terranes or sediment- or crystalline-hosted uranium deposits. Radiolysis involves a complex series of reactions that includes hydrogen as a final product (Fig. 1) (Lousada et al. 2016).
The geologic hydrogen model also differs from the petroleum model in terms of gas preservation and seal capacity. Hydrogen is highly reactive in both biotic (Gregory et al., 2019) and abiotic (McCollom and Seewald, 2013) processes and is thought to be consumed before forming large accumulations. Hydrogen is also smaller in size than other hydrocarbons, which impacts the sealing capacity of potential accumulations. Finally, the timing of gas generation between the two models is different by orders of magnitude. Hydrogen generation can occur on a timescale of days to weeks during serpentinization, while hydrocarbon generation occurs on a timescale of millions of years (similar to radiolysis).
HYDROGEN PROSPECTIVITY IN THE UNITED STATES
The U.S. Geological Survey (USGS) recently published a methodology and a series of maps showing the estimated prospectivity of geologic hydrogen
United States (after Gelman et al., 2025).
resources throughout the conterminous United States (Fig. 2; Gelman et al., 2025). The prospectivity map integrates 21 layers of geological and geophysical data that are representative of hydrogen system components and combines them to determine the relative prospectivity for geologic hydrogen across the study area. Because there is uncertainty in the presence of these components in the subsurface, a chance of sufficiency (COS) methodology was used to establish fractional probabilities of each component’s presence and effectiveness. The COS for each layer was assigned based on interpretations of the geologic hydrogen model and broad knowledge of the geology of the conterminous United States. To learn more about the data and methods, including data layers used, risk analysis, and uncertainty quantification, see Gelman et al., (2025).
Results of the modeling effort indicate that there is relatively greater potential in areas such as the mid-continent of the U.S., the central California coast,
and northern Texas. The maps also highlight elevated prospectivity in the Rocky Mountain region, specifically in the areas in and around the Williston Basin in Montana and North Dakota, and the four-corners region of Colorado, Utah, Arizona, and New Mexico (Fig. 2).
HYDROGEN PROSPECTIVITY IN THE ROCKIES
The Rocky Mountain region has high prospectivity for geologic hydrogen accumulations due to numerous geologic factors. First, the region has the potential for all three types of geologic hydrogen sources described above (Fig. 3) (Gelman et al., 2025). It should be noted that potential sources from overmature, organic-rich rocks were not modeled. Specifically, there are serpentinization-type sources in Montana, Wyoming, and Idaho (Fig. 3A), and radiolysis and deep sources in nearly the whole region (Figs. 3B and 3C). Second, the Rocky Mountain
FIGURE 2: Map showing prospectivity of geologic hydrogen in the conterminous
A. Serpentinization COS
C. Deep sources COS
D. Combined Source COS
FIGURE 3:
Maps showing the composite chance of sufficiency (COS) for A) serpentinization sources, B) radiolysis sources, C) deep sources, and D) combined sources. See Gelman et al., 2025 for more information. The red rectangles highlight the Rocky Mountain region.
B Radiolysis COS
0
FIGURE 4: Maps of prospectivity of geologic hydrogen in the A) northern Rocky Mountain region and B) southern Rocky Mountain Region. The maps are overlain with orange and red circles that show occurrences of geologic hydrogen and helium greater than 0.5 and 0.3 mole percent, respectively. Hydrogen occurrences greater than 5 mole percent are labeled accordingly. Symbol sizes correlate with concentration. Data are from the U.S. Geological Survey, 2019, Zgonnik, 2020, and Brennan et al., 2021.
D eta ile d a nd ac c ura te g eo lo gy at yo u r fin g ertip s in Pe tra , Ge o Grap h ix, A rc GIS , A cc u Map , ge o S C OU T an d o th er d ig ital ma p pin g a p plica tion s
We ste rn USA
Geol ogi cal Edge Set
Ene rgy Al te rnati ve s & Cri ti cal Mine ral s - USA
We ste rn Cana da Geol ogi cal Edge Set
Ene rgy Al te rnati ve s & Cri ti cal Mine ral s - Ca nada
Ea ste rn USA & Ea st ern Ca nada
Geol ogi cal Edge Set
Cent ral USA
Geol ogi cal Edge Set
Me xi co
Geol ogi cal Edge Set
Map la ye rs p rov ided in s ha pe file fo rma t fo r ea sy impor t into a ll ma ppin g app lic at ions .
De liv er ab le s inc lude : f orma tion limits , o utc ro ps, su bc rop e dge s , O &G fie ld s, st ruc tu ra l eleme nt s, re ef s, sh ore lin es , c ha nne ls, pro duc tion f airw a ys , s ha le ga s tr en ds, st ru ct ure con tou rs , iso pa chs , g en era l cult ure , r ene w able & no n-r en ew ab le ene rg y pr ojec ts , min era l dep os it s, mine s, Pet ra T he mat ic Ma p pro je ct s, G eoG ra phix G e oA tla s pro je c ts , Ar cG IS M XD a nd La y er f ile s, re giona l c ro ss -s ec tion s, an d full te ch nica l s upp ort .
For mo re inf orma tio n: Joe l H a rding at + 1 4 03 87 0 8 12 2 joe lha rding@ g eoe dg es .c om ww w.ge oe dge s.c om
1988, Map of sedimentary basins in the conterminous United States: U.S. Geological Survey Oil and Gas Investigation Map OM–223, 1 sheet, scale 1:5,000,000, https://doi.org/10.3133/ om223
https://fuelcellsworks.com/news/helix-exploration-strikes-helium-and-hydrogen-at-ingomar-domes-first-well , August 28, 2024.
Gelman, S.E., Hearon, J.S., and Ellis, G.S., 2025, Prospectivity mapping for geologic hydrogen (ver. 1.2, January 22, 2025): U.S. Geological Survey Professional Paper 1900, 43 p., https://doi. org/10.3133/pp1900 .
Gregory, S.P., Barnett, M.J., Field, L.P., and Milodowski, A.E., 2019, Subsurface microbial hydrogen cycling—Natural occurrence and implications for industry: Microorganisms, v. 7, no. 2, art. 53, 27 p., https://doi.org/10.3390/ microorganisms7020053 .
Lousada, C., Soroka, I., Yagodzinskyy, Y., Tarakina, N.V., Todoshchenko, O., Hänninen, H., Korzhavyi, P.A., Jonsson, M., 2016, Gamma radiation induces hydrogen absorption by copper in water. Scientific Reports, v. 6, 24234, https://doi. org/10.1038/srep24234 .
Lundine, M.A., and Trembanis, A.C., 2021, Using convolutional neural networks for detection and morphometric analysis of Carolina Bays from publicly available digital elevation models: Remote Sensing, v. 13, no. 18, art. 3770, 27 p., https://doi.org/10.3390/rs13183770 .
Maiga, O., Deville, E., Laval, J., Prinzhofer, A.,
and Diallo, A.B., 2023, Characterization of the spontaneously recharging natural hydrogen reservoirs of Bourakebougou in Mali: Scientific Reports, v. 13, art. 11876, 13 p., https://doi. org/10.1038/s41598-023-38977-y
McCollom, T.M., and Seewald, J.S., 2013, Serpentinites, Hydrogen, and Life. Elements, v. 9, p. 129-134, https://doi.org/10.2113/ gselements.9.2.129 .
Milkov, A.V., 2022, Molecular hydrogen in surface and subsurface natural gases—Abundance, origins and ideas for deliberate exploration: Earth-Science Reviews, v. 230, art. 104063, 27 p., https://doi.org/10.1016/j. earscirev.2022.104063 .
U.S. Geological Survey [USGS], 2019, Energy geochemistry database: U.S. Geological Survey provisional database, https://certmapper.cr.usgs.gov/ data/apps/geochem-db/ .
Zgonnik, V., Beaumont, V., Deville, E., Larin, N., Pillot, D., and Farrell, K.M., 2015, Evidence for natural molecular hydrogen seepage associated with Carolina Bays (surficial, ovoid depressions on the Atlantic coastal plain, province of the USA): Progress in Earth and Planetary Science, v. 2, art. 31, 15 p., https://doi.org/10.1186/ s40645-015-0062-5
Zgonnik, V., 2020, The occurrence and geoscience of natural hydrogen—A comprehensive review: Earth-Science Reviews, v. 203, art. 103140, 51 p., https://doi.org/10.1016/j.e arscirev.2 020.103140
HYBRID LUNCH TALK
Speaker: Dr. Christine Griffith
Date: May 7, 2025 | 12:00 pm - 1:00 pm
Reconciling Depositional And Sequence Stratigraphic Models in the Upper Cretaceous Austin Chalk of the Texas Gulf Coast and the Niobrara Formation of the Western Interior Seaway
The Upper Cretaceous Austin Chalk in south and central Texas is the same age and has similar pelagic carbonate composition and thickness as the Niobrara Formation in the Western Interior Seaway, but the two formations have very different depositional and sequence stratigraphic models. Sequence stratigraphic interpretation is easier in the Texas Gulf Coast than in the Western Interior Seaway. The Austin Chalk is mainly pelagic carbonate, with a dip direction consistently toward the Gulf of Mexico. The Niobrara Formation has two directions of basinal dip and two types and sources of sediment: siliciclastic sediment, mainly from the west, and pelagic carbonate, from the east.
The Austin chalk was deposited as a carbonate ramp, with updip facies being thoroughly burrowed and downdip facies laminated and organic-rich. In contrast, the Niobrara stratigraphic model interprets the cleanest, most bioturbated chalk units as deposited in the deepest, most oxygenated water, and laminated and organic-rich marl units interpreted as regressive low-stand deposits. Thickness and facies variations in Niobrara sequences are attributed to structural movement, eustacy, and currents. The Austin Chalk was affected by
similar controls, but the asymmetry and angular truncation of the stratigraphic sequences indicates that structural movement was more important than eustacy.
A possible model to reconcile the Austin chalk and Niobrara observations emphasizes the similarity between the Texas Gulf Coast and the eastern flank of the Western Interior Seaway. Thoroughly burrowed, shallower water facies are represented by the basal trangressive Fort Hays Member; younger oxygenated chalk on the east flank is mostly eroded. Deeper water basinal chalk and marl sediments were oxygen deficient, due to restriction across a southern sill. Periodic movement of the axis of the Western Interior Seaway caused Niobrara facies variations. The Niobrara carbonate ramp extended downdip into intermittently anoxic water when thrust loading caused the basin axis to shift westward and siliciclastic input to diminish. As western highlands were eroded, regression shifted the axis of the basin eastward. Distal marl-rich units of the middle and upper Niobrara Formation were moved by bottom currents past the basin axis up onto the east flank of the Seaway where they transgressed over the normal east flank chalk sedimentation.
CHRISTINE GRIFFITH worked for Shell Oil as petroleum geologist and team leader in exploration and development projects onshore and offshore United States, Nigeria, and Brazil. After retirement, she received her Ph.D.in Geology from Texas A&M University with a dissertation on the regional sequence stratigraphy of the Upper Cretaceous Austin Chalk in south and central Texas. Christine’s previous degrees were a BS in Geology from the University of Illinois, and a MS in Geology from the University of Wisconsin. She is a longtime member of the AAPG and House of Delegates, a member of the Houston and South Texas Geological Societies, the Rocky Mountain Association of Geologists, and a licensed professional geologist in Texas.
Speaker: William R. Drake
Date: June 4, 2025 | 12:00 pm - 1:00 pm
A Mass-Balance Organic Geochemistry Approach To Characterizing Hybrid Unconventional Plays
Examples from the Montney and Green River Formations
Presenter: William R. Drake, Kimmeridge Energy
Unconventional oil and gas plays range from true source-rock mudstones with little to no reservoir lithofacies to tight conventional reservoirs with little to no source rock potential. Most unconventional systems fall somewhere along this spectrum and can be considered hybrid plays. Quantifying the degree of self-sourcing and/or hydrocarbon migration are critical for spatially characterizing the variability of hybrid systems. Several mass-balance organic geochemistry techniques are employed here to quantify
hydrocarbon generation for comparison to resource in place and to produced oils. Two disparate formations and basins are used as examples: the Triassic Montney Formation (marine) of the Western Canadian Sedimentary Basin and the Eocene Green River Formation (lacustrine) of the Uinta Basin. These case studies highlight the importance of correctly characterizing unconventional systems and suggest implications ranging from identifying migration pathways to horizontal well-placement strategy.
WILLIAM R. DRAKE is senior geologist with Kimmeridge Energy, focusing primarily on asset-scale to basin-scale characterization of stratigraphy, source rocks, and overall petroleum systems in most of the basins from Texas to western Canada. He holds a B.S. in geological science from the University of California, Santa Barbara and an M.S. in Geology from the University of Northern Arizona, where he researched the extensional tectonics and stratigraphy of Baja California Sur and the southern Gulf of California. Before Kimmeridge, Bill worked for Pioneer Natural Resources, QEP Resources, and Jonah Energy. Bill also served RMAG for five years as Executive Editor for the Mountain Geologist.
Veterans Memorial Scholarship
• Andrew Oordt, PhD Candidate, University of Oklahoma
Publication Grants
• Matthew Musso, PhD Candidate, Colorado School of Mines
• Ahmed Ahmed, PhD Candidate, Colorado School of Mines
C. Elmo and Kathleen W. Brown Field Camp Scholarship
• Grant Barnes, Colorado Mesa University
• Harper Peck, Fort Lewis College
• Connor Smith, Western Colorado University
MAY 10-11, 2025
Neil J. Harr Outstanding Senior Award
• Brendan Bialy, Metropolitan State University
• Annie Breyak, Colorado College
• Daniel Kotowski, University of Northern Colorado
• Juliana Kelley, University of Colorado
• Isaac Pope, Colorado School of Mines
• Logan Seymour, Colorado State University
• Morgan Sholes, Colorado Mesa University
• Zane Wasicko, Western Colorado University
• Sophia Werren, Fort Lewis College
IN THE PIPELINE
On the Rocks: Caverns, Hot Springs, Evaporite Collapse, & Karst Field Trip to Glenwood Springs Area Glenwood Springs Area, Glenwood Springs, CO. "With speleological experts Mark Maslyn, Harvey DuChene, and Richard Rhinehart."
MAY 15, 2025
RMAG Coffee Hour 10:00 am - 11:00 am, Little Owl CoffeeTremont, 401 17th St., Denver
MAY 17, 2025
On the Rocks: Dotsero Crater Meet at the Woolly Mammoth Park & Ride at 8:00 am. " Trip Leaders: Wendy Bohrson, Professor, Colorado School of Mines Coleader, Valerie Strasser, volcanology PhD candidate, Colorado School of Mines. Trip Coordinators: David Schoderbek and Ron Parker"
MAY 20, 2025
RMAG & AADE Happy Hour Barrels and Bottles, 1055 Orchard St., Golden, CO 80401
OUTCROP ADVERTISING RATES
Publish with…
Expanded geologic focus:
• Entire greater Rocky Mountain area of North America
• West Texas and New Mexico to northern British Columbia
• Great Plains and Mid-Continent region
Why contribute?
• Reach a broad industry and academic audience
• Quarterly peer-reviewed journal
• Permanent archiving includes AAPG Datapages
• Quick turn-around time
• Every subdiscipline in the geosciences
Email: mgeditor@rmag.org
https://www.rmag.org/publications/the-mountain-geologist/
RMAG & AADE Happy Hour
RMAG Coffee Hour
On the Rocks: Dotsero Crater
On the Rocks: Glenwood Springs