LPI Seminar Series
2021
The LPI Seminar Series brings prominent scientists to the LPI to present on a broad array of scientific disciplines that advance our understanding of the solar system. The seminar series, which began in September 1969, has brought many notable contributors from numerous research and academic institutions to the LPI. Seminars are typically held on Thursdays from 3:00-4:00 p.m. US/Central, but dates and times are subject to change. All seminars will be held virtually until further notice.
Sign up for LPI Seminars to receive email notifications of upcoming seminars and details on how to join the virtual seminar. For more information, please contact Patrick McGovern ([email protected]) and Sam Crossley ([email protected]).
See also the Rice University Department of Physics and Astronomy Colloquia and the Department of Earth Science Colloquia pages for other space science talks in the Houston area.
View RecordingsJanuary 2021
Thursday, January 7, 2021 - Virtual, 3:30 PM
Craig Hardgrove, Arizona State University
Searching for Lunar Water with LunaH-Map: Tiny Interplanetary Spacecraft With Big Science and Exploration Goals
LunaH-Map is a new type of NASA planetary science mission manifested for launch on Space Launch System Artemis-1. Following in the footsteps of the MarCO cubesat's successful interplanetary mission, the LunaH-Map spacecraft is a miniaturized, shoebox-sized, interplanetary spacecraft that will use a small ion propulsion system to navigate into lunar orbit and a neutron spectrometer to map enrichments of hydrogen across the lunar South Pole. The maps produced by LunaH-Map will help constrain the amount of hydrogen within permanently shadowed regions, which will inform our understanding of sources and sinks for polar volatile deposits, as well as planning future lunar exploration missions. To R.S.V.P., visit http://ow.ly/JW5b50CZI4h
Thursday, January 14, 2021 - Virtual, 3:30 PM
David A. Kring, Lunar and Planetary Institute
A Subterranean Hydrothermal System and Microbial Nursery Beneath the Floor of the Chicxulub Impact Crater
An expedition sponsored by the International Ocean Discovery Program and International Continental Scientific Drilling Program recovered rock core from the peak ring of the ~180 km-diameter Chicxulub impact crater. Mineral assemblages in the core indicate the crater hosted a substantial and long-lived hydrothermal system. Furthermore, sulfur isotope compositions of pyrite framboids that precipitated in the hydrothermal system indicate it was inhabited by sulphate-reducing thermophilic organisms. The findings support the impact origin of life hypothesis, which posits prebiotic chemistry and the early evolution of life occurred in similar impact-generated systems during the Hadean on Earth and potentially in other planetary systems where similar hydrothermal systems are generated. To R.S.V.P., visit https://bit.ly/3ouPVuT
Thursday, January 21, 2021 - Virtual, 3:30 PM
Casey Honniball, Goddard Space Flight Center
A Tale of Lunar Water
For decades the lunar surface was believed to be anhydrous, however, reports by three independent spacecraft in 2009 changed this view when they detected a 3 µm hydration band on the Moon. The 3 µm absorption band is attributed to hydroxyl (OH) and possibly molecular water (H2O). The band exhibits variations with lunar time of day, temperature, soil maturity, and composition that has been interpreted as variations in water concentrations. Data from an infrared spectrometer, the Moon Mineralogy Mapper (M3) onboard the Chandrayaan-1 spacecraft, is widely used to study the 3 µm band, its spectral range, however, only covers half the hydration band. Due to the limited wavelength range of M3, variations of hydration has been called into question. To investigate the validity of variations in the 3 µm band we used the Spex infrared cross-dispersed spectrograph at the NASA InfraRed Telescope Facility (IRTF) at Maunakea Observatory in Hawaiʻi. Our improved data showed that the variation in hydration is real. But is hydroxyl or water responsible for the variations? Distinction between OH and H2O from spacecraft measurements at 3 µm is difficult due to their similar spectral properties. We have developed a new approach for unambiguous detection of the water molecule on the sunlit lunar surface. At 6.07 µm the fundamental H-O-H bend of H2O is exhibited and is strictly due to H2O without contribution by OH. The only current observatory capable of 6 µm observations of the Moon at 6 µm is the Stratospheric Observatory For Infrared Astronomy (SOFIA). Using data from SOFIA we report the first direct detection of the water molecule on the sunlit lunar surface. To R.S.V.P., visit Https://rb.gy/7z77ll
Thursday, January 28, 2021 - Virtual, 3:30 PM
Cecilia W.S. Leung, Jet Propulsion Laboratory
Regional Atmospheric Dynamics of Water in Valles Marineris, Mars
Water vapor in the planetary boundary layer is substantially influenced by local topographic gradients. Using a mesoscale atmospheric model, we investigate the convergence of regional moist air masses that forces asymmetries between the day-night concentrations of water in the canyon system. I will discuss the conditions under which water ice fogs may form inside Valles Marineris, and the implications for deliquescence and brines that may result from an atmospheric reservoir. To R.S.V.P., visit https://rb.gy/mql0ye
February 2021
Thursday, February 11, 2021 - Virtual, 3:30 PM
Yaray Ku, Harvard University
Potassium isotope anomalies in meteorites inherited from the protosolar molecular cloud
Potassium (K) and other moderately volatile elements are depleted in many solar system bodies relative to CI chondrites, which closely match the composition of the Sun. These depletions and associated isotopic fractionations were initially believed to result from thermal processing in the protoplanetary disk, but so far, no correlation between the K depletion and its isotopic composition has been found. In this talk, I will present our high-precision K isotope data correlated with other neutron-rich nuclides (e.g., 64Ni and 54Cr), suggesting the observed 41K variations of a nucleosynthetic origin. In addition, I will present new K isotope data from individual chondrules and matrix analysis during this talk. Our data support that K isotope anomalies are inherited from an isotopically heterogeneous protosolar molecular cloud, and were preserved in bulk primitive meteorites. To R.S.V.P., visit https://rb.gy/jtztzn.
Thursday, February 25, 2021 - Virtual, 10:00 AM
Jahnavi Punekar
Dept. of Earth Sciences
Jahnavi Punekar, IIT Bombay
The End-Cretaceous Planktic Foraminifera Crisis Linked to Ocean Acidification?
The Cretaceous-Palaeogene boundary event (K-Pg; ~66 Ma) is well known for the demise of >70% life on Earth, including the non-avian dinosaurs. It is one of the BIG FIVE mass extinctions of the Phanerozoic, the only one linked with two triggers- the Chicxulub impact (Yucatan peninsula, Mexico) and Deccan volcanism (India). Recent high-precision U-Pb ages constrain Deccan volcanism between ~66.3 Ma and ~65.6 Ma1. Mercury chemostratigraphy coupled with planktic foraminifera biostratigraphy have enabled unprecedented correlation of the timing, tempo and extent of the end-Cretaceous faunal, climatic and environmental perturbations with Deccan eruptions2. In the main Deccan province (India), the K-Pg boundary is now inferred to be at the top of the Poladpur Formation - a likely catastrophic high-volume eruptive event that lasted <100 kyr1. Proximal K-Pg sequences in the Krishna-Godavari basin intertrappeans (India) document >90% planktic foraminifera species going extinct in response to correlative lava megaflows3. The distal western Tethyan sites reveal a “poor-carbonate-preservation” interval4 with high planktic test fragmentation, increased abundance of opportunist taxa (Guembelitria spp.) and intraspecific dwarfing immediately preceding the K-Pg boundary. Experimental validation of preservation-based proxies lends support to this end-Cretaceous acidification hypothesis. Coeval bulk-rock low magnetic susceptibility and peak mercury signals firmly tie this acidification to ongoing Deccan volcanism5. The biological, taphonomic and geochemical evidence strongly support an ocean acidification interval that persisted for <52 kyr (~2 precession cycles) prior to the K-Pg boundary. The age, duration and nature of this acidification event are better explained by recurrent pulses of Deccan volcanism than the geologically instantaneous Chicxulub impact. To R.S.V.P., visit https://rb.gy/lgjqst.
March 2021
Thursday, March 4, 2021 - Virtual, 10:00 AM
Tim Lichtenberg, Oxford University
Bifurcation of planetary building blocks during Solar System formation
The origin of the Solar System shapes our understanding of the physical and chemical processes that drive planetary formation and early evolution. Geochemical analyses of meteoritic materials and astronomical observations of circumstellar disks provide evidence for a fragmented planet formation process. In the Solar System this manifested as two spatially and temporally separated reservoirs that accreted to form the inner, volatile-depleted and outer, volatile-rich planetary populations. The origin of this dichotomy is unknown. In this talk I will discuss our recent work on how the build-up and earliest evolution of the solar protoplanetary disk can influence the timing of protoplanet formation and their internal evolution. Migration of the water snow line during the Class I and Class II disk stage can generate two distinct bursts of planetesimal formation that sample different source regions of interstellar materials. These reservoirs evolve in divergent geophysical modes and develop distinct volatile contents, consistent with constraints from planetary accretion chronology and volatile composition, thermochemistry of extraterrestrial materials, and the mass divergence of inner and outer Solar System. Our simulations suggest that the compositional fractionation and isotopic dichotomy of the Solar System observed today was initiated by the interplay between disk dynamics, heterogeneous accretion, and internal evolution of forming protoplanets. To R.S.V.P., https://rb.gy/ctorbx
Thursday, March 11, 2021 - Virtual, 3:30 PM
Roger Fu, Harvard University
Understanding magnetism in the protoplanetary disk with high-resolution paleomagnetism
Magnetic fields are thought to govern the lifetime of protoplanetary disks by mediating the inward accretion of gas. At finer scales, magnetic instabilities may have led to the formation of turbulent eddies where the first planetesimals accreted. In recent years, a series of paleomagnetic studies on meteorites have produced the first laboratory constraints on the intensity of magnetic fields in the solar nebula, thereby providing a direct test of theories regarding nebular and planetesimal accretion. I will provide an overview of these experimental results, highlighting the role of new magnetic field imaging technologies and arguing that magnetic fields played a fundamental role in controlling nebular dynamics and may provide evidence for ring and gap structures in the solar nebula. To R.S.V.P., https://rb.gy/p4ge5t
Thursday, March 25, 2021 - Virtual, 3:00 PM
Mike Thorpe, Johnson Space Center
Exploring Mars with Curiosity and Earth for Sedimentary Clues
Preserved in the sedimentary rock record of Mars is an ancient (>3 Ga) history of rivers and lakes, depicting a rich water-lain past that persisted long enough to sculpt landforms and create thick stacks of fluviolacustrine rocks. This rock record illuminates a time when ancient rivers and streams on the surface of Mars physically and chemically altered the terrains and then transported and deposited sediments in downstream basins (i.e., source-to-sink). Since landing in Gale crater, the Mars Science Laboratory Curiosity rover has traversed over ∼400 m of one of these sedimentary basins, exploring mudstones, sandstones, and even conglomerates from the Bradbury and Mount Sharp groups. To help paint the picture of what the paleoenvironment of Mars looked like, we shift our focus to similar environments on Earth, searching for clues to piece together a complex sedimentary story. To R.S.V.P., https://rb.gy/2zmmzy
April 2021
Thursday, April 29, 2021 - Virtual, 3:00 PM
Molly McCanta, University of Tennessee
LPI Seminar: Surface alteration on Venus: How long does a basalt stay a basalt?
Venus surface-atmosphere conditions and compositions are unlike any terrestrial analogues and are therefore difficult to investigate or model without the use of experimental methods. Surface conditions are those of the terrestrial greenschist facies in an atmosphere composed predominantly of CO2, with elevated SO2 variations through time. The geochemical and mineralogic changes in basalts induced by these conditions are not well understood. I will discuss recent experiments to constrain the surface alteration chemistry of Venus as a necessary precursor to future missions that plan to return compositional data to elucidate the evolutionary history of the planet. To R.S.V.P., https://rb.gy/j8ehkr
May 2021
Thursday, May 6, 2021 - Virtual, 3:00 PM
Eva Scheller, Caltech
LPI Seminar: The fate of water on Mars: Tracing water-rock interactions through modelling, satellites, and rovers
There is abundant geological and mineralogical evidence for large volumes of liquid water forming hydrated minerals, fluvial features, and potential ocean shoreline features early in Martian history (~3-4 Ga). For present-day Mars, we observe that most water is stored in the polar cap or subsurface ice. Based on observation, liquid water availability on Mars has decreased over geological time. However, the processes dictating the loss of water remain unresolved. Previous studies suggested that the fractionation of atmospheric D/H can be explained by significant water loss on Mars due to atmospheric escape. We hypothesize instead that the sequestration of water into the crust during the first 1-2 billion years caused the long-term drying of Mars and explains the atmospheric D/H evolution. We model Martian water history through a new integrated hydrogen isotopic model that simulates the three key processes affecting the Martian water budget and hydrogen isotopic composition including crustal hydration or the sequestration of water into the crust, volcanic outgassing of water, and atmospheric escape of water. Our model results show that sequestration of ocean-scale volumes of water in the crust played a large role in the long-term drying of Mars, simultaneously explaining the hydrogen isotopic budget and geological observations of large past water volumes. This has tremendous implications for considerations with regards to understanding climate and the habitability potential of Mars on a geological time scale as aqueous environments are considered to provide both solvents and adequate thermophysical conditions for life. The models presented in this study presents a possible framework for experiments and sampling by the Perseverance rover. To R.S.V.P., https://bit.ly/3ebFMR5
Thursday, May 13, 2021 - Virtual, 3:00 PM
Elizabeth Frank, First Mode
LPI Seminar: Impacts of the Entrepreneurial Space Sector on Planetary Science
Over the past decade, the capabilities of the entrepreneurial space sector have begun to overlap with the interests of the planetary science community. The growth is creating new avenues for scientific investigation and collaboration but also brings challenges that the two communities will have to navigate. This talk will contextualize planetary science within the global space economy, explain the growing potential of smallsats, identify existing or potential challenges, and offer opportunities for scientists to get involved—all from the point of view of a planetary scientist working in commercial space. To R.S.V.P., https://bit.ly/3f69q9H
Thursday, May 20, 2021 - Virtual, 10:00 AM
Cyrena Goodrich, Lunar and Planetary Institute
LPI Seminar: Mixing of NC and CC Reservoirs in Polymict Ureilite Meteorites: Implications for Models of Early Solar System Dynamics
The first few million years of solar system history were characterized by two distinct isotopic reservoirs, NC and CC, interpreted to correspond to the inner and outer solar system, respectively. At some point, however, bulk CC and NC materials became mixed, and several dynamical models offer explanations for how and when this might have occurred. We use xenoliths in polymict ureilite breccias to test such models. Polymict ureilites represent regolith on ureilitic (NC) asteroids. They contain xenoliths of multiple chondritic and achondritic types that represent remnants of impactors. The first combined 54Cr and oxygen isotope data for carbonaceous chondrite-like xenoliths in these breccias show that they were derived from the CC isotopic reservoir. It has been suggested that such xenoliths were implanted into ureilites by outer solar system bodies migrating into the inner solar system ~3-5 Myr after CAI, as in the “Grand Tack” model. However, combined textural, petrologic, and spectroscopic observations suggest that they were added to ureilitic regolith at ~50-60 Myr after CAI, along with ordinary, enstatite, and Rumuruti-type chondrites, as a result of the breakup of multiple parent bodies in the asteroid belt at this time, consistent with the “Early Instability” model. C-type asteroids were already present in inner solar system orbits at this time. We discuss implications for competing dynamical models. To R.S.V.P., https://bit.ly/339Sj19
Thursday, May 27, 2021 - Virtual, 3:00 PM
Jim Bell, Arizona State University
LPI Seminar:
Delta Bound: Early Exploits of the Perseverance Rover in Jezero Crater
After a successful landing on Feb. 18, 2021, the NASA Mars 2020 mission's Perseverance rover science team has been conducting instrument checkout/calibration activities, support activities for the Ingenuity helicopter demonstration mission, and initial scientific reconnaissance of the floor of Jezero crater. That initial reconnaissance has revealed numerous puzzles about the nature and origin/evolution of the crater floor materials, some of which will eventually be sampled and cached for eventual return to Earth. Once the instrument and sampling system checkouts and initial reconnaissance activities have completed, the current plan is to guide the rover to the crater's western delta deposits (about 2 km from the landing site), which are also revealing puzzles and from which more samples are expected to be acquired from an environment that is hypothesized to have once been habitable for life. This presentation will review some of the early activities and key observations so far from the mission. To R.S.V.P., https://bit.ly/3eMuemI
June 2021
Thursday, June 10, 2021 - Virtual, 3:00 PM
Scott Sandford, NASA Ames Research Center
LPI Seminar: The Stardust Sample Return Mission
The NASA Discovery-class Stardust comet sample return mission collected samples from the coma of Comet 81P/Wild 2 and returned them to Earth for study in 2006. The samples were collected at hypervelocities using low-density aerogel as the spacecraft did a flyby of the comet’s nucleus. In this talk, I will begin by giving an overview of the mission that covers (i) the mission design, (ii) the spacecraft, and (iii) the spacecraft’s encounter with Comet/81P Wild 2 and its subsequent return to Earth. This will be followed by a discussion of many of the principal scientific discoveries that resulted from both the comet flyby and the study of the returned samples in terrestrial laboratories (discoveries that will continue to grow as the returned samples continue to be studied in the future). To R.S.V.P., https://bit.ly/3w3usx5
Thursday, June 17, 2021 - Virtual, 3:00 PM
Carolyn van der Bogert, University of Munster
LPI Seminar: Deep Time on the Moon: Development and Application of the Lunar Cratering Chronology
John McPhee used the term "deep time" to describe the vastness of terrestrial geological time in his classic book "Basin and Range" (1981). But, what do we know about deep time on the Moon? And how do we know it? This seminar outlines and discusses the development of the lunar cratering chronology and its applications. The lunar cratering chronology is a tool for connecting lunar geological events to an absolute time scale, and allows a deeper assessment of the geological history of the Moon, the Earth, and even other Solar System bodies. To R.S.V.P., https://bit.ly/2TRTPUo.
Thursday, June 24, 2021 - Virtual, 3:00 PM
Jessica Sunshine, University of Maryland
LPI Seminar: All Comets are Somewhat Hyperactive
Hyperactive comets, those that produce large amounts of water relative to their size, are one of many ways cometary activity is more complex than once thought. We will examine what hyperactivity on a comet entails, fully develop the A’Hearn Model for Hyperactivity based on the analyses of data collected for the Deep Impact encounter of comet 103P/Hartley 2, describe manifestations of hyperactivity suggested on many, if not all, comets, and provide implications of hyperactivity for future cometary exploration. To R.S.V.P., https://bit.ly/34YgYGT.
July 2021
Thursday, July 8, 2021 - Virtual, 3:00 PM
Scott Guzewich, NASA Goddard Space Flight Center
LPI Seminar: Volcanic Climate Warming: Implications for Terrestrial Planet Habitability
Massive volcanic flood basalt eruptions are contemporaneous with most of Earth’s mass extinction events and these types of eruptions appear common to all other terrestrial worlds in our Solar System. Through massive injections of climate-relevant gas species into an atmosphere, flood basalt eruptions can modify a planet’s habitability in complex ways. Using a sophisticated terrestrial climate model, we simulate the climate response of one phase of the Columbia River flood basalt eruption, the most recent such eruption (~15-17 Ma) and one of modest size relative to others in Earth’s history. Unexpectedly, we find a dynamically and radiatively driven climate warming in response to this massive injection of sulfur dioxide into the atmosphere. This has compelling implications for Earth’s history and the role of volcanic activity in the habitability of Mars, Venus, and terrestrial exoplanets. To R.S.V.P., https://rb.gy/axgcls.
August 2021
Thursday, August 5, 2021 - Virtual, 1:00 PM
Catherine Neish, The University of Western Ontario
LPI Seminar: Dragonfly: A Rotorcraft Lander at Titan
On June 27, 2019, NASA announced its next New Frontiers mission: Dragonfly. This audacious mission will send a rotorcraft to explore Saturn’s largest moon Titan, and evaluate its potential for prebiotic chemistry and (possibly) extraterrestrial life. The Dragonfly mission will also give us a countless high-resolution views of this strangely Earth-like moon, showing us how rivers and sand dunes form on an icy moon at 94 K. In this presentation, I will provide a summary of the history of the Dragonfly mission, its scientific goals, and the next steps forward, from launch in 2027 to landing in the mid-2030s. To R.S.V.P., https://bit.ly/3i9wPd9.
Thursday, August 12, 2021 - Virtual, 3:00 PM
Mallory Kinczyk, Johns Hopkins University Applied Physics Laboratory
LPI Seminar: Shaped by Impacts: Understanding the Evolution of Mercury Through Crater Formation and Degradation
Mercury’s surface has been scorched by the solar wind, marred by impact craters, and replaced by effusive volcanic events since its formation. To best understand how Mercury’s crust has changed over time, we can look at impact craters whose shapes, sizes, compositions, and spatial distributions hold clues about Mercury’s evolution and the timing of geological events. This presentation will summarize recent work to characterize impact crater morphology across the surface of Mercury. The results provide the first look at the global distributions of craters at various states of degradation and, therefore, a snapshot into Mercury’s impact cratering history. There is a dearth in the number of ancient craters, potentially indicating multiple ancient impact-related resurfacing events. We will also review the effort to generate the first global geological map of Mercury and insights gained from the process. To R.S.V.P., https://bit.ly/3iALHBB.
Thursday, August 26, 2021 - Virtual, 3:00 PM
Tasha Dunn, Colby College
LPI Seminar: To be (a CK) or not to be (a CK)?: The unusual case of Northwest Africa 10588
The CV and CK carbonaceous chondrites have similar mineralogies, bulk compositions, and oxygen isotopic compositions. These observations led Greenwood et al. (2010) to suggest that the CV and CK chondrite originated from the same parent body. However, compositions of magnetite, Cr-isotopic compositions, and the extent of metamorphism in each group support two separate parent bodies. A single meteorite containing CV and CK lithologies, or material transitional between the two, would provide strong evidence for the single parent body model. However, meteorites containing both lithologies have so far been elusive. We recently acquired a thin section of CK3 chondrite NWA 10588, which was originally described as being “intermediate between normal CV3 chondrites and typical CK4 chondrites” due to its fine-grained (CV-like) matrix and well-equilibrated (CK-like) olivine. Here, we revisit this classification using scanning electron microscopy (SEM) and electron microprobe analysis (EMPA) of the sample’s texture, mineralogy, and mineral chemistry. To R.S.V.P., https://bit.ly/3BNC2iC.
September 2021
Thursday, September 9, 2021 - Virtual, 3:00 PM
Sandra Siljestrom, Research Institutes of Sweden
LPI Seminar: Characterization of spatially resolved organic phases in martian meteorites and on Mars
Organic molecules are important building blocks and signatures of life. Their presence on the surface of Mars was recently confirmed by SAM (Sample analysis on Mars) on the Curiosity rover [1]. The origin of the SAM organic molecules, which is probably part of a large organic macromolecular, though uncharacterized, carbon structure, is unknown [1]. Possible sources include infall from space to the surface of Mars, abiotic origin on Mars and biogenic origin [1]. Martian meteorites, the only samples of Mars we have available on Earth, provide some information on the origin of carbon phases and organic molecules on Mars. These meteorites contain both reduced and oxidized carbon in the form of organic carbon and carbonates [2]. As part of a larger research effort into the organic geochemistry of Martian meteorites, we analysed fresh fracture surfaces of small grains of martian meteorites including Tissint, Nakhla and NWA7034 using in-situ techniques time-of-flight secondary ion mass spectrometry (ToF-SIMS), Scanning Transmission Electron Microscope (SEM)/Energy-dispersive x-ray spectroscopy (EDX) and Raman spectroscopy. The combined instruments provided spatially resolved molecular, elemental and mineral information without being destructive to sample beyond possible surface alteration which provided the opportunity to correlate this data set with other datasets taken. We are able to show that organic diverse phases are spatially resolved to specific mineral phases within the different meteorites providing clues to the origin, of these organic phases [3]. Additionally, in the process of investigating these samples we also developed new sample analysis protocols that can potentially be used on the future returned samples which currently is being collected by the Perseverance rover in Jezero Crater. These analyses, combined with the wealth of other techniques used as part of this study, provide guidance on how to interpret results collected by the rover on rocks in Jezero. The Perseverance rover landed in Jezero Crater in February 2021 where it is currently investigating the local geology with different instruments including spatially resolved ones such as SHERLOC and PIXL. The first rock core was recently successfully collected by Perseverance from the crater floor of Jezero. As a returned sample scientist on the Mars 2020 team, I provide expertise on which sample to collect especially ones that might contain organic matter. Jezero crater appears to contain several different geological units that have high potential for preserving organic matter such as the delta and the marginal carbonates. However, to really understand the Martian organic carbon cycle also other samples such as igneous and regolith samples need to be collected. To R.S.V.P., https://bit.ly/3se5JVG.
Thursday, September 23, 2021 - Virtual, 3:00 PM
Joseph O'Rourke, Arizona State University
LPI Seminar: Is Venus Cooling Quickly or Slowly?
Venus, like all planets, is an engine that converts heat into interesting phenomena. In this seminar, we will debate how fast this engine is running. Some models posit that Venus loses heat from its interior slowly in the absence of plate tectonics. However, recent work shows that many geologic features could be associated with high heat flow. We will explore the implications for the mantle dynamics, internal structure, and magnetic history of Venus. Fortunately, the newly selected missions to Venus will help resolve this debate. To R.S.V.P., https://bit.ly/3nPlgLq.
Thursday, September 30, 2021 - Virtual, 12:00 PM
Mark Fox-Powell, The Open University
LPI Seminar: Ocean-surface exchange at the icy ocean worlds: Combining insights from experimental and field analogue approaches
Ice-covered moons in the outer solar system contain vast oceans of liquid water, where ongoing water-rock interactions may provide the necessary conditions to support microbial life. While the oceans are locked under kilometres of solid ice, processes such as cryovolcanism can deliver ocean materials to the surface, where they are accessible by spacecraft. In this talk, I will present recent experimental insights into ocean/surface interactions at Saturn’s moon Enceladus, and the implications for how microbial biomass could be entrained in cryovolcanic plumes and delivered to space. I will also outline results from field work at unique brine springs in the Canadian High Arctic, which form large-scale deposits of salts analogous to those remotely detected on Europa’s surface. Investigating natural (bio)geochemistry in these springs provides insights into how such processes may be archived on the surface of Europa and other ocean worlds. I hope to convince you that the integration of experimental, modelling and analogue approaches is key to interpreting spacecraft observations, paving the way for upcoming missions such as NASA’s Europa Clipper and ESA’s Jupiter Icy moons Explorer (JUICE). To R.S.V.P., https://bit.ly/3CVf3SF.
October 2021
Thursday, October 7, 2021 - Virtual, 3:00 PM
Mark Panning, NASA Jet Propulsion Laboratory
LPI Seminar: Planetary Seismology: Nearly Three Years on Mars and a Return to the Moon
InSight has been recording seismic data nearly continuously since landing on Mars in November 2018. This mission has not been without challenges, including deploying the heat flow probe deep into the surface, and fighting to keep the solar panels clear in the absence of dust-clearing dust devils. While on the surface, we have observed hundreds of seismic events, which have let us determine key characteristics of the martian crust, mantle, and core. Meanwhile, NASA has recently selected a set of geophysical instruments, including the Farside Seismic Suite (FSS), that has instruments derived from InSight, to fly on a commercial lander to Schrödinger basin on the far side of the Moon. This will be the first seismic data recorded anywhere on the Moon since the Apollo instruments were turned off in 1977. FSS is the most sensitive seismometer ever to record on the Moon and the first-ever on the far side of the Moon. To R.S.V.P., https://bit.ly/3zFnBLn.
Thursday, October 21, 2021 - Virtual, 3:00 PM
Adeene Denton, Purdue University
LPI Seminar: Blown wide open: Searching for oceans in the outer solar system with giant impacts
Giant impacts have influenced many planetary bodies in our solar system. The massive basins left behind provide a critical probe into the subsurface of planetary bodies, as their morphology may directly reflect the thermal and mechanical structure of the target’s interior. Connecting giant impacts to their associated structural and tectonic features, which may be global in scale, provides a novel means to reconstruct the geologic history of worlds whose interiors remain difficult to access. In this talk, I will focus on Sputnik Planitia, Pluto's largest impact basin, and use impact simulations to investigate its formation conditions, morphology, and proposed association with geologic features elsewhere on the surface. By reproducing proximal and distal features associated with the giant impact that formed Sputnik Planitia, I will provide insights into improved constraints on Pluto's interior, including core composition, ice shell structure, and the possibility of a liquid subsurface ocean. To R.S.V.P., https://bit.ly/3ETC6ih.
November 2021
Thursday, November 18, 2021 - Virtual, 11:00 AM
Ke Zhu, Paris Globe Institute of Physics
LPI Seminar:Chromium Isotopic Insights into Early Solar System Evolution and Origin of Terrestrial Planets
Chromium (Cr) isotopes play an important role in cosmochemistry and planetary science because they are powerful tools for dating (53Mn–53Cr short–lived chronometry), tracing (54Cr nucleosynthetic anomalies) the origins of the materials, and studying the processes involved in volatile element fractionation and planetary differentiation (Cr stable isotopic fractionation). I combine these three approaches by using state-of-the-art mass spectrometry (TIMS and MC-ICP-MS). In this talk, I will mainly introduce the application of Cr isotopes for understanding the formation and origin of 1) chondrites; 2) chondrules; 3) Earth, Moon, Mars and other terrestrial planets in our solar system. To R.S.V.P., https://bit.ly/3EBbh1u.
