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1:00 am - Career Center Walk-in Hours

Career Center Walk-in Hours

  Start: September 3, 2015 at 1:00 am     End: September 3, 2015 at 4:00 am
 Location:JGB 2.112
 Contact:Maurine Riess; Jennifer Jordan, mriess@jsg.utexas.edu; jjordan@jsg.utexas.edu, 2-7673; 2-8093

3:30 pm - De Ford Lecture Series: Bayani Cardenas

De Ford Lecture Series: Bayani Cardenas

  Start: September 3, 2015 at 3:30 pm     End: September 3, 2015 at 5:00 pm
 Location:Boyd Auditorium
 Contact:Patrick Stafford, 512-471-5172

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10:30 am - UTIG Seminar Series: Roger Buck, Lamont-Doherty Earth Observatory

UTIG Seminar Series: Roger Buck, Lamont-Doherty Earth Observatory

  Start: September 4, 2015 at 10:30 am     End: September 4, 2015 at 11:30 am
 Location:PRC, 10100 Burnet Road, Bldg 196, Rm 1.603, Austin, TX 78758
 Contact:Luc Lavier, luc@ig.utexas.edu, 512-471-0455
 URL:Event Link
"The Mechanics of Extension in Very Different Areas of Plate Convergence: Reverse Subduction Exhuming Ultra-High Pressure Rocks in New Guinea, and Normal Faulting and Tsunami generation during the Tohoku-Oki Earthquake "

Abstract:

The controversy over the exhumation of ultra-high pressure (UHP) rocks centers on whether it involves rising of pieces of crust detached from subducted continental lithosphere or an entire subducted plate that undergoes "eduction", i.e. reverse subduction. A new thermomechanical model of continental subduction shows that these apparently contrasting mechanisms can occur together: Crust subducted deep enough is heated and weakened, causing limited diapiric rise, while crust subducted to shallower depths retains strength and is exhumed only by eduction. The model also shows for the first time how eduction followed by seafloor spreading can occur in a zone of regional convergence. This occurs spontaneously when subduction of buoyant crust causes a subduction zone to "lock up" in one place causing a new subduction zone to form in another. The model is consistent with many features of the youngest region of UHP rock exhumation on earth: the D'Entrecasteaux Islands of Papua New Guinea.

The Tohoku-oki earthquake was not only the costliest natural disaster in history it was the best monitored. Several observations suggest that the massive near-trench seafloor motion that produced the huge tsunami was linked to normal fault offset. Also, for the first time it was shown that a large subduction earthquake was followed by extensional aftershocks in a broad region of the upper plate. Inspired by the Tohoku data, researchers have searched for and found upper plate extensional aftershocks associated with several other subduction earthquakes that produced large tsunami. Numerical models show that a long-term reduction in slab dip can generate enough extensional stress to cause normal faulting over a broad region of the upper plate. During the inter-seismic period, when the subduction interface is locked, extensional fault slip is suppressed by the relative compression of the upper plate. The relief of compressional stresses during dynamic weakening of the megathrust triggers a release of bending-related extensional strain energy. This mechanism is analogous to the breaking of a pre-stressed concrete beam supporting a bending moment when the compressional pre-stress is removed.



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3:30 pm - De Ford Lecture Series: Marc Hesse

De Ford Lecture Series: Marc Hesse

  Start: September 10, 2015 at 3:30 pm     End: September 10, 2015 at 5:00 pm
 Location:Boyd Auditorium
 Contact:Patrick Stafford, 512-471-5172

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10:30 am - UTIG Seminar Series: Matthew Siegler, Planetary Science Institute

UTIG Seminar Series: Matthew Siegler, Planetary Science Institute

  Start: September 11, 2015 at 10:30 am     End: September 11, 2015 at 11:30 am
 Location:PRC, 10100 Burnet Road, Bldg 196, Rm 1.603, Austin, TX 78758
 Contact:Krista Soderlund, krista@ig.utexas.edu, 512-471-0449
 URL:Event Link
"Polar Ice and Physical Evidence of Lunar True Polar Wander"

Abstract:

The earliest dynamical and thermal history of the Moon is not well understood. Surprisingly, this history may be recorded by the hydrogen deposits near the Lunar poles. These deposits (likely water ice) can only survive if they remain in permanent shadow. If the Moon's orientation has changed, so have the location of the shadowed regions. The polar hydrogen deposits have been mapped by orbiting neutron spectrometers, and their observed spatial distribution does not match the expected distribution of water ice inferred from present-day lunar temperatures. This is in stark contrast to the volatile distribution observed within a similar thermal environment at Mercury's poles. Here we show that polar hydrogen preserves evidence that the Moon's spin axis has shifted - the hydrogen deposits are antipodal, displaced equally from each pole along opposite longitudes. From the direction and magnitude of the inferred reorientation, and analysis of the lunar figure, we find that this change in the spin pole, known as true polar wander, was caused by a low-density thermal anomaly beneath the Procellarum region. Radiogenic heating within this province resulted in major mare volcanism and altered the density structure of the Moon, changing its moments of inertia. This resulted in true polar wander consistent with the observed remnant polar hydrogen. This anomaly still exists and partly controls the current orientation of the Moon. Procellarum was most geologically active early in lunar history, implying that polar wander initiated long ago and that a large portion of the measured polar hydrogen is ancient, recording early delivery of water to the inner solar system. This hypothesis not only provides a uniquely viable explanation for the antipodal distribution of lunar polar hydrogen, but also connects polar volatiles to the geologic and geophysical evolution of the Moon and the bombardment history of the early solar system.

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5:00 pm - Annual Tailgate Party

Annual Tailgate Party

  Start: September 12, 2015 at 5:00 pm     End: September 12, 2015 at 7:00 pm
 Location:Holland Family Student Center, Jackson Geology Building on UT Campus
 Contact:Kristen Tucek, ktucek@jsg.utexas.edu, 512-471-2223

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10:00 am - Geosciences Career Fair

Geosciences Career Fair

  Start: September 14, 2015 at 10:00 am     End: September 14, 2015 at 3:00 pm
 Location:SAC 2.410 Ballroom
 Contact:Maurine Riess, mriess@jsg.utexas.edu, 512-232-7673
 URL:Event Link

12:00 pm - Soft Rock Seminar: Chris Omelon

Soft Rock Seminar: Chris Omelon

  Start: September 14, 2015 at 12:00 pm     End: September 14, 2015 at 1:00 pm
 Location:JGB 2.222

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5:15 pm - Career Info Session-BP

Career Info Session-BP

  Start: September 15, 2015 at 5:15 pm     End: September 15, 2015 at 6:15 pm
 Location:JGB 4.102

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3:30 pm - De Ford Lecture Series: Matt Jackson, UC Santa Barbara

De Ford Lecture Series: Matt Jackson, UC Santa Barbara

  Start: September 17, 2015 at 3:30 pm     End: September 17, 2015 at 5:00 pm
 Location:Boyd Auditorium
 Contact:Patrick Stafford, 512-471-5172

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10:30 am - UTIG Seminar Series: Chris Lowery, UTIG

UTIG Seminar Series: Chris Lowery, UTIG

  Start: September 18, 2015 at 10:30 am     End: September 18, 2015 at 11:30 am
 Location:PRC, 10100 Burnet Road, Bldg 196, Rm 1.603, Austin, TX 78758
 Contact: John Snedden, UTIG, jsnedden@ig.utexas.edu, 512-471-0452
 URL:Event Link
"Controls on the Development of Anoxia in the Cretaceous Western Interior Seaway, USA"

Abstract:

The Cretaceous Period (145-66 Ma) was a time of elevated global temperatures superimposed on fluctuating climate regimes and repeated biotic turnover. It recorded several major perturbations of the carbon cycle, characterized by widespread deposition of organic-rich black shale and benthic and photic zone dysoxia to euxinia, termed oceanic anoxic events (OAEs). The last two of OAEs, the Cenomanian-Turonian OAE2 and the Coniacian-Santonian OAE3 are well-preserved in the Western Interior Sea (WIS) of North America. The expression of these OAEs in the WIS differs both from each other and from contemporaneous open-ocean sections. Despite decades of research, questions remain about the role of oceanographic parameters (sea level, water mass source and character, terrestrial runoff, stratification, productivity, circulation) on the development (or not) of organic-rich shales and anoxic to dysoxic conditions in the WIS. This study utilizes the paleoecology of planktic and benthic foraminifera (marine protists with a hard shell, or "test," that is commonly preserved in the geologic record) and bulk rock geochemical data to address the broad question "How did oceanographic changes effect the development of OAEs in the Western Interior?"

A transect of sites in the Eagle Ford Shale of Texas is used to understand the connection between the well-studied OAE2 interval of the WIS (Greenhorn Formation) and the open ocean, which appears to have been controlled by a sill at the SE aperture of the WIS that was overcome by rising sea level in the late Cenomanian, ventilating the sea. The poorly understood development of OAE3 in the central Western Interior is studied in the Niobrara Formation in Colorado, Kansas, and New Mexico and equivalent rocks further west. Foraminiferal trends through this interval show a slow increase in dysoxia prior to the "onset" of OAE3 recorded by other proxies. Above this level, benthic foraminifera disappear and a stressed planktic assemblage remains unchanged for ~3 million years. This suggests a threshold for anoxia that, once exceeded, pushed the WIS into a new equilibrium. Trends observed during OAEs suggest that sea level change is the principle control on the redox state of the sea: transgressions are associated with continually improving oxygenation due to increasing ventilation of the sea, and regressions are associated with deteriorating oxygenation and the deposition of organic carbon due to greater stratification.


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12:00 pm - Soft Rock Seminar: Chenglin Gong

Soft Rock Seminar: Chenglin Gong

  Start: September 21, 2015 at 12:00 pm     End: September 21, 2015 at 1:00 pm
 Location:JGB 2.222

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6:00 pm - Alumni Reception during GCAGS in Houston

Alumni Reception during GCAGS in Houston

  Start: September 22, 2015 at 6:00 pm     End: September 22, 2015 at 8:00 pm
 Location:Andalucia Tapas Restaurant & Bar-1201 San Jacinto Ste. 161 in Houston
 Contact:Kristen Tucek, ktucek@jsg.utexas.edu, 512-471-2223
All members of the Jackson School community are invited! So whether you are living and working in Houston, attending GSAGS, or just in town on business, we hope you will join us to connect and network.

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3:30 pm - De Ford Lecture Series: Mike Blum, Univ of Kansas

De Ford Lecture Series: Mike Blum, Univ of Kansas

  Start: September 24, 2015 at 3:30 pm     End: September 24, 2015 at 5:00 pm
 Location:Boyd Auditorium
 Contact:Patrick Stafford, 512-471-5172

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9:00 am - Friends and Alumni (FANs) Board Meeting

Friends and Alumni (FANs) Board Meeting

  Start: September 25, 2015 at 9:00 am     End: September 25, 2015 at 4:00 pm
 Location:Jackson Geology Building, UT campus
 Contact:Kristen Tucek, ktucek@jsg.utexas.edu, 512-471-2223

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12:00 pm - Soft Rock Seminar: Steven Goldstein

Soft Rock Seminar: Steven Goldstein

  Start: September 28, 2015 at 12:00 pm     End: September 28, 2015 at 1:00 pm
 Location:JGB 3.222

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