Events

Habitability Seminar: Dr. Ken Wisian, University of Texas at Austin

A seminar from the Center for Planetary Systems Habitability

Speaker: Dr. Ken Wisian, Associate Director, Environmental Division, Bureau of Economic Geology, and Research Scientist, Center for Space Research, Cockrell School of Engineering, University of Texas at Austin

Title: Geothermal Energy in the Outer Solar System

https://habitability.utexas.edu/events/

UTIG Discussion Hour: Joshua Russell, Brown University

Speaker: Joshua Russell, Brown University

Title: Rift-to-Drift: Uncovering the relic lithospheric signature of continental breakup offshore eastern North America

Special Seminar Online: Surui Xie, Scripps Inst. of Oceanography, UCSD

Speaker: Surui Xie, Scripps Institution of Oceanography, UC San Diego

Host: Shuoshuo Han

Title: Geodesy at The Land Margins: Challenging yet Rewarding

Abstract: High precision space geodetic techniques have been widely used in measuring Earth changes due to slow or rapid processes. While they continue to provide important observations for a variety of geophysical studies, technical limitations have hampered their applicability in monitoring several key Earth processes in critical zones, such as tidal-timescale or shorter timescale variations of the outlet glaciers and mélange in the polar regions, as well as strain accumulation and release processes in the offshore portion of subduction zones. Continued development of terrestrial and marine geodetic techniques can overcome some of the difficulties and thus complement existing methods. However, they can be technically challenging. In this talk I will present several examples of space, terrestrial, and marine geodetic techniques in observing some key Earth processes at the marginal zones, including: 1) observing marine-terminating glacier and mélange motion in Greenland with terrestrial radar interferometry; 2) measuring subduction zone interface locking and transient events with GPS; and 3) shallow water seafloor motion and water level monitoring with a GPS spar-buoy.

LEO Seminar Series: Krista Soderlund and Maria Nikolinakou

UT Paleontology Seminar: Jasmine Nelson

Jasmine Nelson (Jackson School of Geosciences, Clarke Lab)

Title: Phylogenetic Proxies for Hearing in Extinct Reptiles.

DeFord Lecture: Laurel Larsen

Multiscale flow-vegetation feedbacks in low-gradient landscapes

About Dr. Laurel Larsen (UC Berkeley)

How flowing water structures the form and function of landscapes, with emphases on the Florida Everglades, wet meadows across the US, and intermittent streams in coastal California; forefront of surface processes, ecology, and hydrology

DeFord Lecture Series
Since the 1940’s, the DeFord (Technical Sessions) lecture series, initially the official venue for disseminating EPS graduate student research, is a forum for lectures by distinguished visitors and members of our community. This is made possible through a series of endowments.

Dr. Wei Yu - UTA, Petroleum & Geosystems Engineering

Hot Science At Home "The Fate of Food"

What will we eat in a bigger, hotter and smarter world? Climate models show that global crop production will continue to decline due to drought, heat, and flooding. Meanwhile, the world’s population is expected to grow another 30 percent by midcentury. So how, really, will we feed nine billion people sustainably in the coming decades? Hear how Amanda Little spent three years traveling through a dozen countries and as many U.S. states in search of answers to that question.

For additional information visit http://www.hotsciencecooltalks.org.

UTIG Discussion Hour: Zachary Sickmann, UTIG

Speaker: Zachary Sickmann, Postdoctoral Fellow, UTIG

Title: Thinking about sand mining from source to sink

Special Seminar: Benjamin Keisling, Lamont-Doherty Earth Observatory

To watch the recorded talk online please request a link from costa@ig.utexas.edu.

Speaker: Benjamin Keisling, Lamont-Doherty Earth Observatory, Columbia University

Host: Tim Goudge

Title: Past as prologue: how archives help us predict the fate of Earth’s ice sheets and the future of our discipline

UT Paleontology Seminar: Dr. Pamela R. Owen

Dr. Pamela R. Owen (Texas Memorial Museum, The University of Texas at Austin)

Presentation topics: The role of paleontology for informal science education and public outreach, Capromeryx, Slaughter Creek site

DeFord Lecture: Jennifer Druhan

Isotopic reactive transport: Towards improved quantitative models for the fate of metals and carbon in near surface environments

About Dr. Jennifer Druhan (University of Illinois Urbana-Champaign)

Identifying the underlying processes contributing to chemical variability during reactive transport through porous media using measurements and modeling of associated stable isotope fractionations. My recent work has involved integrating stable isotope systems in numerical models of reactive flow and transport for a variety of field and laboratory experiments.

DeFord Lecture Series
Since the 1940’s, the DeFord (Technical Sessions) lecture series, initially the official venue for disseminating EPS graduate student research, is a forum for lectures by distinguished visitors and members of our community. This is made possible through a series of endowments.

Dr. Matthew A. Malkowski - Stanford University

UTIG Seminar Online: Xiaohua Xu, Scripps Inst. of Oceanography

Speaker: Xiaohua Xu, Scripps Institution of Oceanography, UC San Diego

Host: Harm Van Avendonk

Title: Probing Earth’s Shallow Crust with Space Geodesy

Abstract: Contemporary earthquake hazard models hinge on an understanding of how strain is distributed in the crust and the ability to precisely image the earthquake rupture. The development in these fields is driven by the newer generation of space geodetic tools. In this presentation, I’ll be focusing on the shallow most part of the Earth’s crust, and bridge the mechanisms of reduced shallow rupture (shallow slip deficit) with the widely distributed shallow faulting. I show that a large part of the shallow slip deficit is due to incomplete data coverage near the fault when combined with a regularized inversion, and thus the associated seismic hazard may have been underestimated. Thus, near-fault geodetic observations are indispensable to fully image large strike-slip events. I’ll then present our newest findings associated with the 2019 Ridgecrest earthquake sequence, where we found numerous previously unmapped strain concentrations (fractures) with an InSAR phase-gradient technique. Most fractures are displaced in the direction of tectonic stress (prograde), while a number of them are displaced in the opposite direction (retrograde). Our analysis shows that both types of fractures are caused by the stress change from the main rupture – prograde fractures are triggered slip while retrograde fractures are strain concentrations in a weak compliant fault zone. The different mechanisms can be understood if the shallow part of the faults are always critically stressed. And a major implication is that shallow tectonic strain is widely distributed in diffuse strike-slip areas like the Mojave shear zone, which also explains the larger deficit in the shallow earthquake ruptures near Ridgecrest.

Bio: Xiaohua Xu received his B.S. degree in geophysics from the University of Science and Technology of China in 2012 and his Ph.D degree in Earth Sciences at University of California San Diego in 2017. Since then he’s been working as a postdoctoral researcher at Scripps Institution of Oceanography. His research interest broadly lies in imaging earthquakes, understanding strain/moment accumulation, crustal deformation and plate tectonics, InSAR processing techniques, GNSS InSAR integration, etc. He is one of the core developers of the open source InSAR processing software GMTSAR.

Special Seminar Online: Tian Dong, UT Jackson School of Geosciences

Speaker: Tian Dong, Department of Geological Sciences, UT Jackson School of Geosciences

Host: John Goff

Title: Sediment Dispersal Dynamics at a Tectonically Active River Delta

Abstract: River deltas build land in coastal regions mainly by the process of lobe avulsion. Through multiple avulsion cycles, deltas grow basinward. However, many studies on delta building often assume time continuous subsidence. In nature, deltas residing at active margins are affected by discrete subsidence events. These events can drive adjustments in delta morphology, avulsion dynamics, and development of stratigraphy. To explore such impacts, detailed measurements of delta and basin morphology, spanning one and half centuries, were collected using remote sensing and field surveys, from the Selenga River delta, residing along the active Baikal Rift Zone, Russia. At the Selenga Delta, over multiple millennia, earthquake associated tectonic subsidence events lower portions of the topset below mean lake surface elevation, creating shallow embayments near the coast. We find that Selenga Delta lobe avulsion is triggered predominately by the newly created accommodation from the partially subsided lobe. Our results also indicate that gravel is arrested near the coast on the subaerial delta, while only mud is transported to the basin, as confirmed by core data. As active rift basins are perennial sediment sinks, impacts of discrete subsidence events on stratigraphy at Lake Baikal could be used to inform more generalized basin-evolution models. Leveraging the data and findings derived from the Selenga Delta, we also develop a practical method, based on graph theory, that uses remotely sensed variables to predict partitioning of water discharge and total sediment discharge in distributary coastal networks. This method have broad modeling applications for large-scale delta systems worldwide, where field data may be limited.

Dr. Frank Peel - A Jurassic Lost World Revealed...

A Jurassic Lost World Revealed; Spectacular Images of the Base of the Louann Salt Reveal a Drowned Topography

Frank J Peel and Gillian M Apps

We care how giant evaporites were deposited because they tend to be formed at times of global crisis, such as extreme climate events, supercontinent breakup, oceanographic upheaval, etc. Understanding these critical times helps us to understand how the global geosystem works.

But for giant salt deposits, the present is NOT the key to the past; there is no modern analog! Past workers have used modern salt basins as analogs to these giants of the past, but they are fundamentally different in scale and process.

Some salt deposits, such as the Zechstein, contain interbedded non-salt sediment layers that can reveal the paleogeography of the salt basin and the water depth, and show how those evaporites were deposited. But the Jurassic Louann Salt of the Gulf of Mexico is different; it contains no such layers, and there has been no obvious way to investigate the basin paleogeography.

As a result, there have been many uncertainties – was the basin shallow-water, or a deep marine basin? Was it deposited slowly, over millions of years, or extremely rapidly, over thousands of years? When salt deposition ended, was an exotic tectonic subsidence mechanism required to get to the depths seen in later sediments, or was it already a deep basin?

Now, for the first time, there is hard evidence that answers some of these questions. A unique seismic data set shows, in exquisite detail, the nature of the landscape on the floor of the basin on the eve of salt deposition. The data reveals beautiful images of a semi-arid pre-salt world, with wadis and rivers draining from rugged, mountainous highlands, flowing across what is now the bottom of the basin, into a large pre-salt lake in the middle of the basin. The mid-basin lake, which we have named Lake Jackson in honor of Martin Jackson, was deep; at least 750m within our data set, probably much deeper in the middle. The pre-salt lake margin was steep, with fault scarps that were eroded above lake level, and fan-deltas deposited below lake level. Water level in the lake lay about 1km below global sea level.

Flooding of this pre-salt world was rapid, possibly catastrophic, creating the Louann Sea, a body of water several km deep. The shallow-water depositional model for the Louann is disproved.

Combined with geochemical information, we can infer a depositional model in which the salt was precipitated in deep water, with evaporation matched by seawater influx. Deposition was extremely rapid, possibly the fastest documented episode of sustained sediment deposition known to science.

With this knowledge, we can now explain the post-salt evolution of the basin, and we can begin to constrain the nature of the pre-salt sediments within the basin, which remain untested and unknown.

UTIG Seminar Online: Jessie Pearl, United States Geological Survey

To watch the recorded talk online please request a link from costa@ig.utexas.edu.

Speaker: Jessie Pearl, United States Geological Survey

Host: Chris Lowery

Title: Multiproxy reconstructions of late Holocene coastal climate and extreme events

Abstract: The densely populated coastlines of the United States face unique natural hazards and are at the forefront of global change phenomena, and including sea level rise, rising global temperatures, changing storm frequency and intensity, and growing anthropogenic pressures. Adaptation to, and mitigation of, the impacts of these phenomena rely on extensive and accurate records of coastal stressors and an understanding of their secondary ecological effects. Instrumental data of physical and biological changes along the coast extend, at best, about 120 years and are usually much shorter. Thus, longer high-resolution records of coastal phenomena are essential to determine the potential range and return interval of storms, floods, droughts, and earthquakes. Multi-centennial to multi-millennial length tree-ring records are annually-resolved proxies for environmental change that fill these critical data gaps. These records ultimately improve coastal management and hazard planning, as well as detect and attribute trends in regional climate phenomena. Using climate field reconstructions, a network of subfossil ‘drowned’ forests and co-located sediment records, radiocarbon, and paleoecology studies I show how we can date and characterize both long term trends and punctuated extreme events along the northeast and northwestern coastlines of the United States.

Habitability Seminar: Josh Krissansen-Totton, UC Santa Cruz

A seminar from the Center for Planetary Systems Habitability
 
Title: Anticipating exoplanet biosignatures with coupled atmosphere-interior evolution models 

Speaker: Josh Krissansen-Totton, NASA Sagan Fellow, Department of Astronomy and Astrophysics, University of California, Santa Cruz

https://habitability.utexas.edu/events/

UTIG Discussion Hour: The GeoVISION RTX Mentor Experience

Speakers: Dana Thomas, Dan Breecker, Evan Ramos and Michelle Tebolt, UT Jackson School of Geosciences

Title: JSG: The GeoVISION RTX Mentor Experience

Doctoral Defense: Junwen Peng

Please join the Department of Geological Sciences for the final doctoral examination of Junwen Peng’s PhD project, “Heterogeneity characterization and genetic mechanism of deepwater fine-grained sedimentary rocks during Icehouse Period: A case study.” This PhD was supervised by Dr. Xavier Janson and Dr. Qilong Fu; committee members include: William L Fisher, Timothy M Shanahan, Kitty L Milliken, and Ronald J Steel.

The defense is open to all members of the University community and the public.

https://gradschool.utexas.edu/academics/theses-and-dissertations/doctoral-candidacy/oral-examinations/upcoming

UT Paleontology Seminar: Sinjini Sinha

Sinjini Sinha (Jackson School of Geosciences, Martindale Lab)

Research Interests: Lagerstatten taphonomy, Early Jurassic, Ichthyofaunal diversity

Dr. Saad J. Saleh - Rice University

Fleets of Autonomous Vehicles for Enhanced Geophysical Sensing:

The Role of Formation Control Systems

The development of autonomous vehicles has revolutionized geophysical and geochemical sensing.  However, most of the current deployments employ such vehicles simply as individual platforms.  Yet, many of the new emerging applications require deployment of a large fleet of unmanned vehicles moving collectively in a formation constrained to maintain a fixed geometric shape while maneuvering.  This added complexity can be quite challenging for any geophysical data acquisition program, but it is particularly formidable for underwater platforms where GPS signals are unavailable and alternative localization strategies can be rather costly or inaccurate.

The advent of Formation Control Theory in recent years has provided a theoretical foundation for understanding and controlling formations and swarms through simple localized inter-vehicle exchange of information.  In this talk, we present recent results from an analytical and numerical feasibility study to explore applicability of formation control theory to geophysical data acquisition.  Specifically, we consider the problem of conducting a streamer-free mobile marine seismic survey.  To this end, we examine a typical marine seismic survey layout, focus on the possibility of replacing the cable-linked receivers by sensor-carrying autonomous vehicles, and address the questions of inter-vehicle sensing and control algorithms required to robustly maintain the desired acquisition geometry while maneuvering.  We present numerical simulation results to demonstrate the feasibility of this approach and to address the resulting tradeoff between cost and complexity on the one hand and robustness in the face of potential sensor failures on the other hand.

UTIG Seminar Series: Ram Tuvi, UTIG

Speaker: Ram Tuvi, Postdoctoral Fellow, UTIG

Host: Zeyu Zhao

Title: Imposing physics-based sparsity in large scale inversion algorithms

Abstract: Inversion algorithms provide a way to estimate physical properties of an unknown object from a data set. There are numerous applications for these algorithms in medical imaging, computational seismology, target identification, electromagnetic inverse scattering, and subsurface imaging. However, these problems are nonlinear and ill-posed. Exact numerical algorithms are limited to small scale problems in terms of wavelength. With the increasing computational power, inversion techniques are becoming more efficient for realistic and large-scale problems. To tackle the challenges above, one uses some physical approximations. Still, these problems are often formulated as iterative schemes and contain large data sets. An a priori knowledge of the data is essential to address these algorithms correctly. This utilization must rely on a proper understanding of the wave propagation physics and physics-based signal processing.

In this talk, we present a physics-based sparse data approach for large scale inversion algorithms. Recent developments in wave technology have enabled us to gather reliable data, which provides a high degree of spatial resolution of the propagation environment. We present both forward and inverse models including a derivation of analytical models for the measured data. We show a direct relationship between the data and specific targets. This relation enables an a-priori sparse representation of the inverse problem, which leads to fast, robust, and efficient algorithms. We demonstrate these features with several numerical examples.

UTIG Discussion Hour: Eric Goldfarb, JSG (PhD Talk)

Speaker: Eric Goldfarb, Graduate Student Fellow, UT Jackson School of Geosciences

Title: Predictive Digital Rock Physics