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9:00 am - Career Center Open House

Career Center Open House

  Start: December 1, 2014 at 9:00 am     End: December 1, 2014 at 12:00 pm
 Location:JGB 2.112 Martineau Career Services Suite
 Contact:Chelsea Ochoa, chelsea.ochoa@jsg.utexas.edu, 5122320893
Visit the Career Center for coffee and bagels.
Learn about upcoming events, internship opportunities and more!
Open to all JSG students.

12:00 pm - Soft Rock Seminar: Rebekah Simon

Soft Rock Seminar: Rebekah Simon

  Start: December 1, 2014 at 12:00 pm     End: December 1, 2014 at 1:00 pm
 Location:JGB 3.222
 Contact:Kealie Goodwin, kealiegoodwin@utexas.edu

4:00 pm - Student Internship Panel

Student Internship Panel

  Start: December 2, 2014 at 4:00 pm     End: December 2, 2014 at 5:00 pm
 Location:JGB 3.222
 Contact:Chelsea Ochoa, chelsea.ochoa@jsg.utexas.edu, 5122320893
Learn about internship opportunities for summer 2015 and hear from students about their experience with different programs. Geared toward undergraduate students.

12:00 pm - iPGST Seminar: Michelle Gevedon

iPGST Seminar: Michelle Gevedon

  Start: December 3, 2014 at 12:00 pm     End: December 3, 2014 at 1:00 pm
 Location:JGB 3.222
 Contact:Nikki Seymour, nikki.m.seymour@utexas.edu

9:00 am - BEG Friday Seminar Series

BEG Friday Seminar Series

  Start: December 5, 2014 at 9:00 am     End: December 5, 2014 at 10:00 am
 Location:BEG Main Conference Room; Building 130; PRC Campus
 Contact:Sophia Ortiz, sophia.ortiz@beg.utexas.edu, 512.475.9588
 URL:Event Link
Estibalitz Ukar
Research Associate
Bureau of Economic Geology
The University of Texas at Austin

The use of Dauphiné twins in quartz as paleostrain (stress) indicators

One of the fundamental challenges of structural analysis is determining the stresses that lead to the formation of geologic structures. For exploration and production, establishing the stress state history of hydrocarbon fields is essential because dynamic mechanisms governed by the stress state present drive oil and gas migration and accumulation. Therefore, paleostress history, rather than the present-day stress state, is responsible for most natural structures in a reservoir. Many paleopiezometers are used to study metamorphic rocks deformed at high temperatures and that underwent large penetrative deformation. In contrast, only mechanical twinning of calcite has been well studied for small strain in low temperature sedimentary rocks, but the results and limitations are hard to assess without independent approaches based on new assumptions. New techniques are needed for measuring paleostresses in low temperature and low strain sedimentary environments, and for developing techniques that compliment and that can be used to validate current methodologies.

Our research on quartz deposits in fractures in siliciclastic reservoirs of oil and gas reveals an opportunity to explore and potentially validate the use of Dauphiné twins in quartz as paleostress history indicators. Recent advancements in electron backscattered diffraction techniques (EBSD) show that Dauphiné twins are widespread in quartz fracture cements that show synkinematic textures. In these cements, the relative sequence of deformation events is recorded in a spatial pattern of crack-seal textures and Dauphiné twins that can be mapped using SEM-based technology. Thermal conditions can be measured from fluid inclusions, and absolute ages of deformation can be inferred quantitatively from known burial and tectonic histories.

Preliminary results from combined SEM-CL imaging and EBSD analyses of two tight gas sandstone formations -the Travis Peak Formation in East Texas and the Nikanassin Formation in the Alberta Foothills- indicate that Dauphiné twins are mechanical twins, and at least in some cases, synkinematic with respect to fracture opening. Contraction directions recorded by Dauphiné twins were estimated using the PT kinematic method of Marrett and Allmendinger (1990), and the orientation of maximum compression was estimated using the graphical P-dihedra method described by Angelier and Mechler (1977). Contraction/compression orientations estimated in this manner are compatible with the tectonic history of the area. These results demonstrate the potential for Dauphiné twinning to be a robust paleopiezometer for sedimentary rocks, in low temperature and pressure environments, during fracture opening and gas and/or oil charge.

10:30 am - UTIG Seminar Series: Graduate Student Presentations

UTIG Seminar Series: Graduate Student Presentations

  Start: December 5, 2014 at 10:30 am     End: December 5, 2014 at 11:30 am
 Location:PRC, 10100 Burnet Road, Bldg 196, Rm 1.603, Austin, TX 78758
 Contact:Sean Gulick/Craig Fulthorpe, sean@ig.utexas.edu/ craig@ig.utexas.edu, 512-471-0483/512-471
 URL:Event Link
Maureen Walton: "Updated Mapping and Seismic Reflection Processing along the Queen Charlotte Fault, Southeastern Alaska"

The Queen Charlotte Fault (QCF) is a dextral transform system that accommodates offset between the Pacific and North America plates in southeastern Alaska and western Canada. The seismically-active margin has recently ruptured in two large earthquake events, including a M7.7 thrust event near Haida Gwaii, Canada. Convergence along the QCF is highest south of 53.2°N due to a restraining bend in the fault, near where the Haida Gwaii thrust event occurred. The Haida Gwaii event is thought to have been caused by incipient underthrusting of the Pacific Plate related to the oblique convergence along the QCF in that region; however, the fault structure near the earthquake is poorly understood and the interface that slipped to cause the earthquake has yet to be explicitly imaged. Through updated seismic reflection processing, fault mapping, and seismic interpretation, we are able to better image and map the QCF along-strike and observe that strain manifestation could be related to fault geometry. We also observe downwarping of oceanic basement crust north of the Haida Gwaii event and suggest that this crust was once located in a more convergent regime, translated north along the QCF to its current position with its flexure “preserved” by sedimentary loading.
Jie Xu: "Sediment Input Pathways from North American Highlands to the Gulf of Mexico Based on Detrital Zircon U-Pb and U-Th/He Dating"


We have collected samples from outcrops across the northern Gulf, from Texas to Florida, in order to discriminate sediment pathways. Most of our data show a mixture of source terranes, including Oligocene volcanic centers, Cordilleran Arc, Laramide uplifts, Grenville, Mid-Continent, Yavapai-Mazatzal, and Appalachian-Ouachita as major provinces and Wyoming and Superior regions as minor provinces. However, major DZ age peaks vary greatly between different samples, providing a means to differentia drainage systems. Five major sediment input pathways are defined: the Paleo-Rio Grande, Paleo-Red, Paleo-Mississippi and Paleo-Tennessee rivers and a local river system in Florida draining from Appalachians. The Paleo-Rio Grande and Paleo-Red rivers show a significant sediment input from Oligocene volcanic centers, Laramide uplift regions and the Cordilleran Arc, whereas the Paleo-Tennessee River received most of its sediments from Appalachian-Ouachita and Grenville basement. The Paleo-Mississippi River lies within a transitional zone between western and eastern North American drainage systems.

12:00 pm - iPGST: Edgardo Pujols

iPGST: Edgardo Pujols

  Start: December 10, 2014 at 12:00 pm     End: December 10, 2014 at 1:00 pm
 Location:JGB 3.222
 Contact:Nikki Seymour, nikki.m.seymour@utexas.edu

9:00 am - BEG Special Seminar

BEG Special Seminar

  Start: December 11, 2014 at 9:00 am     End: December 11, 2014 at 10:00 am
 Location:BEG Main Conference Room; Building 130; PRC Campus
 Contact:Sophia Ortiz, sophia.ortiz@beg.utexas.edu, 512.475.9588
 URL:Event Link
Dr. Robert N. Erlich
President & CEO
PanAtlantic Exploration

Exploration for Cretaceous Deep-water Reservoirs Along the African and South American Equatorial Margins: A Petroleum Systems View

Cretaceous deep-water reservoirs deposited along the equatorial margins of African and South American have recently been the focus of industry interest and exploration spending. Activity has historically been focused on Campanian – Cenomanian fans and channels, sourced by Albian lacustrine and Cenomanian deep-water marine shales. Traps are formed by a combination of structural (normal faults and anticlinal drape) and stratigraphic (sediment bypass and permeability changes) factors. Seals are provided by regionally extensive Upper Turonian shales and limestones.

Key technical risks include:

Access to charge/charge focus and volume
• Genetic potential of the source
• Charge timing
Trap definition – where are the potential leak points?
• Poor seismic imaging – velocity control, calibration, and models
• Complex reservoir architecture – unconnected or overly connected
Reservoir presence and deliverability
• No/poor geologic modelling
• Discounting the impact of burial diagenesis
Hydrocarbon phase prediction
• Basin modelling – poor/lack of calibration to data points (wrong gradients)
• Geophysical rock properties – spotty success with AVO and attributes

In spite of the fact that >100 wells have been drilled for this play concept along the margins since 2007, only five commercial discoveries have been made. The key reasons for this are likely due to:
Structural deformation (secondary folding/faulting)
• Why? Traps are breached
Lack of clearly defined traps
• Why? Multiple seals/trapping points are required for large (commercial) columns Lack of direct access to charge/charge focus/charge volume
• Why? Complicated migration pathways allow for thief zones in 3D; functioning kitchens?
No significant sand-dominated river systems with high-maturity sands
• Why? There is an optimum distance where deliverability impacts commercial rates and column heights

The play has been expanded to the equatorial margin of South America with limited success to date. While the play will likely work in some geographies and geologic settings, it clearly cannot be transferred to other areas without acknowledging that significant additional risks may be encountered.

9:00 am - BEG Friday Seminar Series

BEG Friday Seminar Series

  Start: December 12, 2014 at 9:00 am     End: December 12, 2014 at 10:00 am
 Location:BEG Main Conference Room; Building 130; PRC Campus
 Contact:Sophia Ortiz, sophia.ortiz@beg.utexas.edu, 512.475.9588
 URL:Event Link
Peter Flaig
Research Associate, BEG-QCL
Bureau of Economic Geology

A potential high-latitude signature in the Prince Creek Formation (Early Maastrichtian) of greenhouse Arctic Alaska

The Prince Creek Formation (PCF) of Arctic-Alaska preserves a Maastrichtian lower delta-plain succession deposited at 82-85° north latitude, making it a true paleopolar greenhouse ecosystem. Distinctive, recurring facies and sedimentary-pedogenic structures found throughout the PCF coupled with carbon and oxygen isotope data from dinosaur tooth enamel, pedogenic siderite, and brackish-water clams provide potential evidence of a high-latitude signature on this Arctic coastal plain.

Strata record deposition in meandering and fixed (anastomosed) distributary channels, and on associated floodplains. Crevasse splay complexes and floodplain paleosols make up the bulk of the preserved stratigraphy. High suspended-load concentrations and frequent flooding may have driven repeated crevassing. Inclined heterolithic stratification (IHS) composed of rhythmically repeating sandstone-mudstone couplets found in all channels was initially thought to reflect tidal influence; however, ubiquitous roots in the IHS and on channel thalweg trough cross-bedding may also evidence a flashy system with regular, drastic reductions in discharge. Hyperpycnites identified in prodelta deposits of the Schrader Bluff Formation fed by PCF rivers also indicate regular floods and fluctuating discharge. In addition, several dinosaur bonebeds found on PCF floodplains exhibit a recurring facies pairing consistent with deposition by fine-grained, viscous hyperconcentrated flows. Paleo-histological data from bones shows seasonal variation in bone growth rates and indicate that the juvenile dinosaurs consistently died in spring. We propose that bonebeds record exceptional discharge events, possibly generated by seasonal snowmelt from the nearby Brooks Range and/or large storm events. Floods entrained abundant mud-ash stored on point bars and floodplains, increasing suspended sediment concentrations and generating hyperconcentrated flows that transported the remains of dinosaurs onto floodplains adjacent to distributary channels. Stable oxygen isotope analysis on dinosaur tooth enamel indicates that dinosaurs ingested 18O orographically depleted runoff from the Brooks Range. Analysis on pedogenic siderite also shows 18O depleted water proposed to result from increased rainout effects from an intensified hydrological cycle. Isotopes measured from umbo to shell-edge in PCF clams reveal full growth cycles of co-trending C and O isotopes. When compared with other isotopic data, results suggest that depleted meteoric water consistently mixed with sea water in clam-rich estuaries.

No evidence of cryogenic processes (e.g. involution, undulation, or rotation) is found in PCF paleosols, instead compound-cumulative paleosols similar to modern entisols and inceptisols exhibit well-defined horizonation. Soil-forming processes were repeatedly interrupted by alluviation, resulting in weak soil development. Paleosols contain abundant organics, carbonaceous root traces, Fe-oxide depletion-coatings, and zoned peds indicating periodic waterlogging, anoxia, and gleying. In contrast, Fe-oxide mottles, ferruginous-manganiferous segregations, bioturbation, and illuvial clay coatings in the same soils indicate recurring oxidation and drying-out of soils. Abundant pedogenic illite/smectite in paleosols is interpreted to result from the illitization of smectite derived from floodplain volcanic ash. Pedogenic clays like these typically form in soils subject to alternating wetting and drying. Evidence of repeated wetting and drying and frequent influx of alluvial material into paleosol horizons suggests a nearby alluvial system with variable discharge that is perhaps affected by seasonal flooding.

There is no modern analogue for an ecosystem that experiences warm temperatures under a polar-light regime. Although the recurring facies, sedimentary-pedogenic structures, and isotopes discussed here, when looked at individually, do not seem to exhibit a high-latitude signature, taken as a group these characteristics suggest a flashy system, with flashiness likely driven by extreme seasonality related to the paleopolar light regime. We suggest that this is the high-latitude signature in the PCF.

12:00 pm - Alumni Networking Reception in conjunction with AGU

Alumni Networking Reception in conjunction with AGU

  Start: December 17, 2014 at 12:00 pm     End: December 17, 2014 at 2:00 pm
 Location:Thirsty Bear Brewery, San Francisco CA
 Contact:Kristen Tucek, ktucek@jsg.utexas.edu, 512-775-6745