Events

Tailgate - UT vs. West Virginia

Join us for the Jackson School of Geosciences Annual Tailgate Party!

UT v. West Virginia
WHEN: Saturday, October 1 | 4:30-6:30pm (kick-off) 
WHERE: Holland Family Student Center and Munib & Angela Masri Family Courtyard at the Jackson Geological Sciences Building at 23rd & San Jacinto

RoKafe

Faculty Meeting

DeFord Lecture | Brad Foley

Planetary interior controls on the habitability of rocky exoplanets by Brad Foley, University of Pennsylvania

Abstract: An essential factor for the habitability of rocky exoplanets is climate regulation via the carbonate-silicate cycle. Without such regulation, uninhabitably hot or cold climates can form, even for planets lying within their host star’s habitable zone. The planetary interior plays a critical role in driving the carbonate-silicate cycle, as it controls how volatiles are cycled between surface and interior over time. I will explore these links between interior dynamics and climate evolution considering the role of a planet’s tectonic state, thermal evolution, and area of exposed land. While it has long been thought that plate tectonics might be essential for the carbonate-silicate cycle to regulate climate, I show that the same stabilizing feedbacks can also operate on planets lacking plate tectonics. However, these results point to the importance of active volcanism, which is in large part controlled by the budget of radiogenic elements (U, Th, and K) a planet acquires during formation. Radiogenic heat producing element (HPE) abundances are not directly measurable in other planets, but estimates can be made based on the composition of stars planets orbit. I therefore use measured HPE abundances in stars to determine the likely range of heat budgets for rocky exoplanets and estimate how long they can stay volcanically active in a stagnant-lid regime. The results show many known exoplanets, including the Trappist system, may be too old to still be volcanically active today. Finally, I discuss the role of exposed land in sustaining habitable surface conditions. Whether sea floor weathering provides a climate regulating feedback, like weathering of exposed land, has been long debated. Based on recent estimates of the seafloor weathering rate and its dependence on temperature, ocean pH, and spreading rate, I show that planets lacking exposed land can potentially regulate their climates better than planets with land. This result opens up the possibility of habitable climates on waterworld planets.

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.

UTIG Seminar Series: Kiki Schulz, UT Oden Institute

Speaker: Kiki Schulz, Research Fellow, UT Oden Institute for Computational Engineering and Sciences

Host: Patrick Heimbach

Title: Mixing in a changing Arctic Ocean

Abstract: The Arctic Ocean is a distinct and beautiful marine environment, and severely affected by the ongoing climate crisis. A nearly perennial ice cover in most regions of the Arctic has maintained a very specific structure of the underlying ocean, characterized by low nutrient availability and light-limitation, which favored the development of a highly specialized ecosystem featuring many species exclusively found at high latitudes. In response to anthropogenic warming, which is strongly amplified in the Arctic compared to the global average, sea ice cover is further and further retreating in the summer months, and the local ice-free seasons become longer. Without a separating layer of ice in between, energy transfer from the atmosphere to the ocean is facilitated, providing the kinetic energy to transport both heat and nutrients from deep water layers of Atlantic origin to the ocean surface. There, enhanced nutrient availability – in combination with longer open water seasons – can alter the structure of the ecosystem, allowing invasive Atlantic species to out-compete the endemic Arctic species. Despite its importance for the coupled Arctic system, the spatial and temporal distribution of enhanced vertical mixing, and the underlying energy conversion mechanisms, are still not conclusively mapped. This talk will start with a brief outline of the history and current state of oceanographic research in the Arctic Ocean, before summarizing recent advances in the understanding of turbulent mixing and transport in the Siberian Seas.

Alumni Reception at GSA in Denver, CO

Join the Jackson School of Geoscience for an alumni reception at GSA’s annual meeting in Denver, Colorado.

WHEN: Monday, October 10 | 5:30-7:30pm local time
WHERE: Henry’s Tavern | 500 16th St Mall Suite 184B, Denver, 80202, CO, USA

UTIG Seminar Series: Jonathan Delph, Purdue University

Speaker: Jonathan Delph, Assistant Professor, Department of Earth, Atmospheric and Planetary Sciences, Purdue University

Host: Shuoshuo Han

Title: Linking heterogeneous expressions of subduction along the Cascadia margin

Abstract: Spatial correlations between lateral heterogeneity in geophysical, seismogenic, and tectonic features is observed along the Cascadia margin. Both the overriding and downgoing plate have been invoked to play the dominant role in controlling along-strike correlations between seismogenic behavior, potential field measurements, morphological/tectonic characteristics, and seismic structure; however, significant feedbacks likely exist between the two. Our recent seismic images suggest that zones of basal accretion of material from the downgoing plate to the overriding plate may link the seismogenic, geological, and morphological expression of subduction in Cascadia. In the northern and southern portions of the forearc, this “subcreted” material is also characterized by thick (~10 km) anomalously low shear-wave velocity zones. The thickness, high internal reflectivity, and low Bouguer gravity signatures likely indicate that this subcreted material is composed of dominantly (meta)sedimentary material that has been emplaced through successive subcretion events over geologic timescales. Furthermore, the anomalously low velocities and spatial correlation with high non-volcanic tremor (NVT) density and short slow slip recurrence intervals indicate that these regions are fluid-rich. While 1st order variations in the fluids that control NVT and slow slip likely result from differences in the permeability of the downgoing slab as inferred from its stress state and the distribution of intraslab seismicity, these subcreted packages likely represent thick, vertically-impermeable regions in the lower crust that further accentuate this correlation. Variability in the amount of subcretion explains patterns of exhumation and uplift along the Cascadia margin and the resulting forearc topography over geologic timescales, and is likely controlled by some combination plate interface geometry/rheology and overriding plate architecture.

Doctoral Defense | Sophie Goliber

The final doctoral examination for SOPHIE GOLIBER has been scheduled for OCTOBER 14; 10AM; JGB 4.102 (Barrow Family Conference Room) and VIRTUAL.

The PhD project “Controls on terminus change of marine terminating glaciers in Greenland over the last 40+ years ” was supervised by Dr. Ginny Catania.

Committee members include: Timothy Goudge, Jamin Greenbaum, Patrick Heimbach, Kyle Spikes

ZOOM link:  https://utexas.zoom.us/j/6340999132

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

RoKafe

DeFord Lecture | Elowyn Yager

It’s not always rainbows and butterflies: vegetation influences on rivers beyond sediment deposition and meander formation by Elowyn Yager, University of Idaho

Abstract: Vegetation is ubiquitous in river and delta systems and is often used to restore river channels with the assumption that vegetation addition will cause sediment deposition and stabilize channel banks. Uncertainties remain as to whether vegetation actually enhances sediment deposition because of the competing influences of vegetation drag and vegetation induced turbulence. Vegetation can also cause significant spatial variability in deposition/erosion that complicate common correlations between vegetation and channel planform. We use laboratory experiments at a wide range of spatial scales (stem to river reach) to understand the mechanics of turbulence and sediment transport through vegetation, and the impact of vegetation and flow hydrographs on channel morphology. We demonstrate that complex feedbacks between flow hydraulics, channel morphology, and sediment transport during flow hydrographs control whether vegetation causes local deposition or erosion. The role of vegetation in promoting a certain type of channel planform (e.g., meander) may depend on vegetation location within the channel and the upstream sediment supply.

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.

UTIG Seminar Series: Sean Peters, Naval Postgraduate School

Speaker: Sean Peters, Assistant Professor, Naval Postgraduate School

Host: Duncan Young

Title: Passive Radar Investigations for Terrestrial and Planetary Radio Glaciology

Abstract: Traditional ice-penetrating radars transmit a powerful electromagnetic pulse and record the echo’s delay time and power to measure ice sheet thickness and subsurface conditions of glaciers. Such observations are critical for understanding and predicting future ice sheet behavior and contribution to global sea-level rise; however, existing ice-penetrating radar systems are resource-intensive in terms of cost, power, and logistics when continuously monitoring ice sheets at both their evolving spatial (local to continental) and temporal (daily to multiannual) scales. In this seminar, I will describe our developed passive radar system and signal processing techniques that leverage ambient radio noise sources (instead of transmitting a powerful radio signal), in efforts to enable cost-effective, low-resource, and ubiquitous monitoring of ice sheets at the desired spatiotemporal scales. First, I present the results of our passive radar sounding demonstration using the Sun to measure ice sheet thickness at Store Glacier, Greenland. I then project the passive radar’s performance and ability to provide valuable glaciological observations (such as melt rates, bed reflectivity changes, and englacial water storage) across Greenland and Antarctica.

In the second part of my presentation, I then extend this technique to enable passive synthetic aperture radar (SAR) imaging using radio-astronomical noise sources (e.g., the Sun and Jupiter’s radio emissions). I conclude by highlighting applications of this technique to planetary remote sensing, such as (1) analyzing solar radio burst candidates for passive sounding using the Mars Reconnaissance Orbiter (MRO) Shallow Radar (SHARAD) and (2) using Jupiter’s HF radio emissions alongside an active VHF radar to correct for ionospheric dispersion and characterize Europa’s ionosphere during a flyby mission.

Mark Helper retirement celebration

Help us celebrate our incredible retiring faculty!

WHEN: Friday, October 21 | 5:00pm – 7:00pm
WHERE: Holland Family Student Center at the Jackson Geological Sciences Building at 23rd & San Jacinto

RoKafe

DeFord Lecture | Jessica Guo

Sensitivity of plant water use to a changing environment by Jessica Guo, University of Arizona

Abstract: The global carbon and water cycles are inextricably linked through plant stomata, as water loss is an inescapable consequence of photosynthesis. Characterizing the sensitivity of plant processes to environmental controls becomes even more urgent as climate warms and precipitation regimes change. As a dryland plant ecophysiologist, I study the sensitivity of water use strategies to seasonal variability and the consequences for ecosystem productivity. In well-watered riparian ecosystems, desert trees differ in their stomatal sensitivity to cumulative atmospheric dryness, which is associated with differences in xylem anatomy. Among dryland species such as creosote bush and Utah juniper, regulation of midday water potential shifts rapidly to allow for greater productivity under episodic precipitation. Broadening our understanding of plant water use strategies as temporally dynamic has the potential to explain why dryland ecosystems are largely responsible for high inter- and intra-annual variability in the terrestrial carbon cycle.

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.

UTIG Seminar Series: Andreas Fichtner, ETH Zurich

This is a hybrid seminar. Join us in the UTIG Seminar Room for coffee, snacks and Dr. Fichtner’s live streamed talk.

Speaker: Andreas Fichtner,  Professor of Seismology & Wave Physics, Institute of Geophysics, ETH Zurich

Host: Sean Gulick

Title: Fiber-optic seismology in volcanic, glacial and other challenging environments

Abstract: Fiber-optic deformation sensing provides new opportunities for seismic data acquisition with high spatio-temporal resolution. The relative ease of deploying fiber-optic cables, or the possibility to piggyback on existing telecom infrastructure make this technology particularly attractive for environments where large numbers of conventional seismic instruments may be difficult to install. These include active volcanoes, glaciers or densely populated urban centers.

In the first, more observational part of this talk, we will present a series of case studies where Distributed Acoustic Sensing (DAS) greatly improved the location of glacial icequakes, enabled the observation of previously unknown volcanic tremor and resonance phenomena, and increased the number of detected seismic events by two orders of magnitude – all relative to data from existing seismometer networks.

In the second, more theoretical part, we will report on the development of a novel fiber-optic sensing system that is based on the transmission of microwave-modulated laser pulses. While being more than 10 times cheaper than most DAS systems, the microwave system allows for interrogation distances of hundreds or thousands of kilometers. We show theoretically that different segments of the fiber can have different sensitivities for deformation sensing, largely depending on fiber curvature. Data from a large-scale experiment in Athens support this theory, thereby suggesting that tomographic imaging in remote regions and in the oceans should be possible.

Doctoral Defense | Yanyao Zhang

The final doctoral examination for YANYAO ZHANG has been scheduled for OCTOBER 28; 2PM; JGB 4.102 (Barrow Family Conference Room).

The PhD project “Elasticity Across The Post-Stishovite Transition In Subducted Basalt” was supervised by Dr. Jung-Fu (Afu) Lin.

Committee members include:

Stephen P Grand

James E Gardner

Jianshi Zhou

Chenguang Sun

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