UTIG Brown Bag: Larry Lawver

Informal weekly presentations by UTIG students and researchers. Bring your lunch!

Speaker: Larry Lawver, Senior Research Scientist, UTIG

More info.

DeFord Lecture Series: Kenny Befus

UTIG Seminar Series: Caroline Morley, UT Austin

Speaker: Caroline Morley, Assistant Professor of Astronomy, UT Austin

Host: Krista Soderlund

Title: Prospects for Observing Exoplanets in the Coming Years with the James Webb Space Telescope

Abstract: As exoplanet astronomers, we currently stand at a threshold: with current and near-future discoveries from TESS, we have now discovered many of the nearby planets we share our neighborhood with. The Hubble and Spitzer space telescopes, as well as dedicated ground-based efforts, have provided a taste of the diversity of atmospheres these worlds have. The largest and hottest have atmospheres like stars, with metals and ions. Many have atmospheres that, like those in the solar system, are filled with clouds/hazes, but a much larger variety. Some of the smallest planets we’ve observed, the size of the Earth, may retain atmospheres, but at least some appear to have lost their atmospheres during their lifetimes. Armed with these hints (and our increasingly complete census of nearby planets), exoplanet astronomers are chomping at the bit for the next step, which will be facilitated by the launch of the James Webb Space Telescope (JWST): to characterize in detail the atmospheres of our neighbors, large and small. I will discuss some of the types of programs that can be done with JWST that will progress our knowledge of planetary physics the most. I will discuss what the prospects are for gas giants, including those much colder than any discovered to date; for sub-Neptunes, between Earth and Neptune in size, for which no solar system analogs exist, but which are among the most numerous planets; and finally, I will discuss the prospects for observing Earths (both hot and “habitable”) with JWST.

UTIG Brown Bag: Leah Turner, Jasmine Gulick, John Hash

Informal weekly presentations by UTIG students and researchers. Bring your lunch!

Speaker: Leah Turner, Jasmine Gulick, John Hash

More info.

DeFord Lecture Series: Chenguang Sun

DeFord Lecture Series: Emily Stewart

***CANCELLED*** UTIG Seminar Series: Kristine DeLong, Louisiana State

*** NOTE, THIS TALK HAS BEEN CANCELLED ***

Speaker: Kristine DeLong, Associate Professor of Geography, Louisiana State University

Host: Jud Partin

Title: The Alabama Underwater Forest: A Time Capsule from the Last Ice Age

Abstract: In 2004, energetic waves from Hurricane Ivan exposed the stumps of bald cypress trees (Taxodium distichum) preserved in their growth position below the seafloor on the northern Gulf of Mexico continental shelf. These in situ stumps located ~13 km offshore Gulf Shores, Alabama in ~18 m of water represents the only identified submerged Pleistocene forest assemblage found thus far. We dated the site using optically stimulated luminescence and radiocarbon dating yielding ages between 74–42 ka suggesting this wood was preserved for ~50 ka during falling sea levels of the last ice age and eventual transition to the Holocene marine environment. Phase 1 of the project mapped the site area with bathymetric and sub-bottom surveys, characterize the sediment and depositional environment using vibracores, and developed tree-ring, pollen, seed, and foraminifera chronologies to better understand the environment the trees lived in. Foraminiferal assemblage analysis reveals that the transitional layer of interbedded sand and mud above the Pleistocene floodplain facies is late Holocene in origin and is part of a lower shoreface or marine-dominated estuarine environment. Seeds recovered from the Pleistocene floodplain sediments, which also contains woody remnants, generally agrees with pollen results. Stratigraphy within the study area suggests paleo-topographic relief was established prior to 56 ka and persisted until Holocene transgression. This site is likely a bald cypress backwater swamp with little water mixing promoting anoxic conditions in sediments that lead to the preservation of organic materials for more than ~50 ka. We suggest that paleo-topographic relief created enough accommodation space for sediment infill to bury and preserve this forest during the late Pleistocene lowstand. We hypothesized that rapid increases in global sea level occurring ~60 ka and ~40 ka provided opportunities for local floodplain aggradation to bury the swamp thus preserving the tree stumps. We are developing a geophysical methodology to identify and map buried tree remains and a model to predict other forest sites on the continental shelf in Phase 2 that will start this year.

UTIG Seminar Series Online: Kirk Scanlan, UTIG

WATCH A RECORDING OF THE TALK
(Note: The first speaker is the talk's host, Don Blankenship.)

Speaker: Kirk Scanlan, Postdoctoral Fellow, UTIG

Host: Don Blankenship

Title: Radar: Planes, Trains, and Spacecraft(-mobiles)

Abstract: Radar geophysical methods are actively being applied in numerous disciplines across both science and engineering. In each instance, radar measurements are used in new and innovative ways in order to address key technical and societal questions within that field. The large diversification in radar applications yields a deep resource base from which techniques and approaches can be mined and adapted to new cross-discipline problems. In this seminar, I will explore how I have applied radar geophysics in the fields of geotechnical engineering, planetary science, and glaciology with the goal of building a cross-discipline experience base that can then be leveraged to new problems. In geotechnical engineering, I demonstrate how radar measurements have been used to monitor degradation conditions within ballasted railway track foundations. In planetary science, we will discuss how radar instruments on two different spacecraft have been used to characterize the Martian ionosphere. And in glaciology, we will investigate how radar measurements can be used to produce a more consistent estimate of ice thickness in regions of variable bed topography. Finally, I will present opportunities for cross-discipline radar geophysical research, where radar techniques developed for a particular application may be leveraged to help address problems in other fields.