JGR Planets: Constraining Ancient Magmatic Evolution on Mars Using Crystal Chemistry of Detrital Igneous Minerals in the Sedimentary Bradbury Group, Gale Crater, Mars

V. Payré, K. L. Siebach, R. Dasgupta, A. Udry, E. B. Rampe, S. M. Morrison

Abstract

Understanding magmatic processes is critical to understanding Mars as a system, but Curiosity’s investigation of dominantly sedimentary rocks has made it difficult to constrain igneous processes. Igneous classification of float rocks is challenging because of the following: (1) the possibility that they have been affected by sedimentary processes or weathering, and (2) grain size heterogeneity in the observed rock textures makes the small‐scale compositions measured by rover instruments unreliable for bulk classification. We avoid these ambiguities by using detrital igneous mineral chemistry to constrain models of magmatic processes in the source region for the fluvio‐deltaic Bradbury group. Mineral chemistry is obtained from X‐ray diffraction of three collected samples and a new stoichiometric and visual filtering of ~5,000 laser induced breakdown spectroscopy (LIBS) spots to identify compositions of individual igneous minerals. Observed mineral chemistries are compared to those produced by MELTS thermodynamic modeling to constrain possible magmatic conditions. Fractionation of two starting primary melts derived from different extent of adiabatic decompression melting of a primitive mantle composition could result in the crystallization of all minerals observed. Crystal fractionation of a subalkaline and an alkaline magma is required to form the observed minerals. These results are consistent with the collection of alkaline and subalkaline rocks from Gale as well as clasts from the Martian meteorite Northwest Africa 7034 and paired stones. This new method for constraining magmatic processes will be of significant interest for the Mars 2020 mission, which will also investigate an ancient volcaniclastic‐sedimentary environment and will include a LIBS instrument.

Future Texas hurricanes: Fast like Ike or slow like Harvey?

– JULY 6, 2020

Climate change will make fast-moving storms more likely in late 21st-century Texas

Climate change will intensify winds that steer hurricanes north over Texas in the final 25 years of this century, increasing the odds for fast-moving storms like 2008’s Ike compared with slow-movers like 2017’s Harvey, according to new research.

Hurricane Harvey as seen from the International Space Station on Aug. 28, 2017

Hurricane Harvey as seen from the International Space Station on Aug. 28, 2017. (Photo courtesy of Randy Bresnik/NASA)

The study published online July 3 in Nature Communications examined regional atmospheric wind patterns that are likely to exist over Texas from 2075-2100 as Earth’s climate changes due to increased greenhouse emissions.

The research began in Houston as Harvey deluged the city with 30-40 inches of rain over five days. Rice University researchers riding out the storm began collaborating with colleagues from Columbia University’s Lamont-Doherty Earth Observatory (LDEO) and Harvard University to explore whether climate change would increase the likelihood of slow-moving rainmakers like Harvey.

“We find that the probability of having strong northward steering winds will increase with climate change, meaning hurricanes over Texas will be more likely to move like Ike than Harvey,” said study lead author Pedram Hassanzadeh of Rice.

Pedram Hassanzadeh

Pedram Hassanzadeh

Harvey caused an estimated $125 billion in damage, matching 2005’s Katrina as the costliest hurricane in U.S. history. Ike was marked by coastal flooding and high winds that caused $38 billion damage across several states. It was the second-costliest U.S. hurricane at the time and has since moved to sixth. Ike struck Galveston around 2 a.m. Sept. 13, 2008, crossed Texas in less than one day and caused record power outages from Arkansas to Ohio on Sept. 14.

Hassanzadeh, a fluid dynamicist, atmospheric modeler and assistant professor of both mechanical engineering and Earth, environmental and planetary sciences, said the findings don’t suggest that slow-moving storms like Harvey won’t happen in late 21st century. Rather, they suggest that storms during the period will be more likely to be fast-moving than slow-moving. The study found the chances that a Texas hurricane will be fast-moving as opposed to slow-moving will rise by about 50% in the last quarter of the 21st century compared with the final quarter of the 20th century.

Suzana Camargo

Suzana Camargo

“These results are very interesting, given that a previous study that considered the Atlantic basin as a whole noticed a trend for slower-moving storms in the past 30 years,” said study co-author Suzana Camargo, LDEO’s Marie Tharp Lamont Research Professor. “By contrast, our study focused on changes at the end of the 21st century and shows that we need to consider much smaller regional scales, as their trends might differ from the average across much larger regions.”

Hassanzadeh said the researchers used more than a dozen different computer models to produce several hundred simulations and found that “all of them agreed on an increase in northward steering winds over Texas.”

Steering winds are strong currents in the lower 10 kilometers of the atmosphere that move hurricanes.

Map depicting total rainfall from 2017's Hurricane Harvey

Map depicting total rainfall from 2017’s Hurricane Harvey. (Image courtesy of NOAA)

“It doesn’t happen a lot, in studying the climate system, that you get such a robust regional signal in wind patterns,” he said.

Harvey was the first hurricane Hassanzadeh experienced. He’d moved to Houston the previous year and was stunned by the slow-motion destruction that played out as bayous, creeks and rivers in and around the city topped their banks.

“I was sitting at home watching, just looking at the rain when (study co-author) Laurence (Yeung) emailed a bunch of us, asking ‘What’s going on? Why is this thing not moving?’” Hassanzadeh recalled. “That got things going. People started replying. That’s the good thing about being surrounded by smart people. Laurence got us started, and things took off.”

Laurence Yeung

Laurence Yeung

Ebrahim Nabizadeh

Ebrahim Nabizadeh

Yeung, an atmospheric chemist, Hassanzadeh and two other Rice professors on the original email, atmospheric scientist Dan Cohan and flooding expert Phil Bedient, won one of the first grants from Rice’s Houston Engagement and Recovery Effort (HERE), a research fund Rice established in response to Harvey.

“Without that, we couldn’t have done this work,” Hassanzadeh said. The HERE grant allowed Rice co-author Ebrahim Nabizadeh, a graduate student in mechanical engineering, to work for several months, analyzing the first of hundreds of computer simulations based on large-scale climate models.

The day Harvey made landfall, Hassanzadeh also had reached out to Columbia’s Chia-Ying Lee, an expert in both tropical storms and climate downscaling, procedures that use known information at large scales to make projections at local scales. Lee and Camargo used information from the large-scale simulations to make a regional model that simulated storms’ tracks over Texas in a warming climate.

Chia-Ying Lee

Chia-Ying Lee

“One challenge of studying the impact of climate change on hurricanes at a regional level is the lack of data,” said Lee, a Lamont Assistant Research Professor at LDEO. “At Columbia University, we have developed a downscaling model that uses physics-based statistics to connect large-scale atmospheric conditions to the formation, movement and intensity of hurricanes. The model’s physical basis allowed us to account for the impact of climate change, and its statistical features allowed us to simulate a sufficient number of Texas storms.”

Hassanzadeh said, “Once we found that robust signal, where all the models agreed, we thought, ‘There should be a robust mechanism that’s causing this.’”

He reached out to tropical climate dynamicist Ding Ma of Harvard to get another perspective.

“We were able to show that changes in two important processes were joining forces and resulting in the strong signal from the models,” said Ma, a postdoctoral researcher in Earth and planetary sciences.

Ding Ma

Ding Ma

One of the processes was the Atlantic subtropical high, or Bermuda high, a semipermanent area of high pressure that forms over the Atlantic Ocean during the summer, and the other was the North American monsoon, an uptick in rainfall and thunderstorms over the southwestern U.S. and northwestern Mexico that typically occurs between July and September. Hassanzadeh said recent studies have shown that each of these are projected to change as Earth’s climate warms.

“The subtropical high is a clockwise circulation to the east that is projected to intensify and shift westward, producing more northward winds over Texas,” he said. “The North American monsoon, to the west, produces a clockwise circulation high in the troposphere. That circulation is expected to weaken, resulting in increased, high-level northward winds over Texas.”

Hassanzadeh said the increased northward winds from both east and west “gives you a strong reinforcing effect over the whole troposphere, up to about 10 kilometers, over Texas. This has important implications for the movement of future Texas hurricanes.”

Models showed that the effect extended into western Louisiana, but the picture became murkier as the researchers looked further east, he said.

Map depicting total rainfall from 2008's Hurricane Ike

Map depicting total rainfall from 2008’s Hurricane Ike. (Image by Hal Pierce/SSAI/NASA

“You don’t have the robust signal like you do over Texas,” Hassanzadeh said. “If you look at Florida, for instance, there’s a lot of variation in the models. This shows how important it is to conduct studies that focus on climate impacts in specific regions. If we had looked at all of North America, for example, and tried to average over the whole region, we would have missed this localized mechanism over Texas.”

Bedient is the Herman Brown Professor of Engineering and department chair of civil and environmental engineering and director of Rice’s Severe Storm Prediction, Education and Evacuation from Disasters Center. Cohan is an associate professor of civil and environmental engineering. Yeung is the Maurice Ewing Career Development Assistant Professor in Earth Systems Science in the Department of Earth, Environmental and Planetary Sciences.

The research was supported by the National Science Foundation, NASA, the Gulf Research Program of the National Academies of Sciences, Engineering and Medicine’s Early-Career Research Fellowship Program, Rice’s Houston Engagement and Recovery Effort Fund, Columbia’s Center for Climate and Life Fellows Program, the National Oceanic and Atmospheric Administration and the New York State Energy Research and Development Authority. Computational resources were provided by the National Science Foundation’s Extreme Science and Engineering Discovery Environment, the National Center for Atmospheric Research’s Computational and Information Systems Lab and Rice’s Center for Research Computing.

EEPS’s Stand Against Systemic Racism

EEPS Virtual Graduation Ceremony

The most unattainable part of Earth

THREE EEPS GRADUATES RECEIVE COVETED NSF EARTH SCIENCES POSTDOCTORAL FELLOWSHIPS

Three Earth, Environmental and Planetary Sciences 2020 Ph.D. graduates are awarded prestigious National Science Foundation (NSF) Postdoctoral Fellowships – a record for the department. Brandee Carlson, Tian Dong and Andrew Moodie, all from the same laboratory group, receive the highly competitive grant after submitting research proposals to the Division of Earth Sciences at NSF.  The scope of the evaluation considers the scientific merits of the proposal, and the potential for transformative research as well as professional development by training recipients for research and leadership positions.  The grants provide two years of salary and research support at an institution of the fellows choosing.

These postdoctoral fellowships are only offered to early-career scientists, so student supervisors are relied upon to discuss fellowship opportunities with their students during their graduate careers.  Assistant professor Jeff Nittrouer, primary advisor for Carlson, Dong, and Moodie, strongly encouraged them to apply to the NSF program and is thrilled with the results.

“I could not be more proud of them,” says Nittrouer. “Collectively, they’ve shown how a laboratory raises the bar and thrives, demonstrating that scientific success comes from collaborations with fellow students and colleagues, both here at Rice and globally.”

 

EEPS 2020 Ph.D. graduates (L to R) Tian Dong, Brandee Carlson and Andrew Moodie all receive NSF Earth Sciences Postdoctoral Fellowships

 

 

 

“In the past six years, Brandee, Andrew, Tian, and Chen Wu [PhD, 2020] have cultivated a special culture: inclusiveness and sharing of ideas and resources, typifying the mantra that the sum of the parts is greater than the whole.” -Dr. Jeff Nittrouer

 

 

 

 

 

In terms of their upcoming research ventures, they’ll rely on recent experiences, in particular, working in far-flung localities and remote environments.

Brandee Carlson heads to the University of Colorado, Boulder, to collaborate with Prof. Irina Overeem in the Institute of Arctic and Alpine Research. Dr. Carlson is exploring delta front processes of Arctic rivers, focusing research in Greenland, where under warming climate conditions, river sediment supply is increasing due to rapidly retreating glaciers and thawing permafrost. Dr. Carlson plans to investigate how failures on multiple Arctic deltas vary by water and sediment discharge.  Her work includes several field campaigns combined with CU’s extensive remote sensing capabilities. The project dovetails with her previous work on the Yellow River delta but will ultimately expand her expertise to include sediment transport at a variety of delta fronts and climate conditions.

Tian Dong will study how physical processes shape river morphology, working with Dr. Timothy Goudge at the University of Texas at Austin. Tian will develop new metrics to distinguish between meandering and braided river patterns, from sediment deposits, drill cores, remote sensing, and the rock record. The goals are to identify the prevalence of these river types for the past eon of earth’s history and improve groundwater reservoir models.  Ultimately, the metrics may be translatable to the paleoclimate record of other terrestrial planets, including Mars.

Andrew Moodie will collaborate between Stanford University and the University of Texas, working with Drs. Jef Caers and Paola Passalacqua, respectively. Dr. Moodie’s project seeks to improve an understanding of subsurface delta sediment distribution and ground fluid movement, using machine learning algorithms.  The aim is to distinguish how multiple natural and anthropogenic factors, including as sea level change and infrastructure development, influence delta systems.

According to Andrew, “Our understanding of subsurface fluid transport in river deltas is limited.  Improving our ability to manage water resources and mitigate pollutant transport lowers risk to societal health.  And predicting ground-fluid transport relies on models to constrain subsurface composition, however due to the complexity of river-delta environments, accurate assessments are difficult. Using machine learning to better constrain environmental heterogeneity will benefit society and the cultures that live on deltas globally”.

Although the group splits at the end of the academic term, all agree that their experiences at Rice have collectively enhanced their future as scientists and mentors.

“Lessons learned abroad were brought back here” [to Rice] says Brandee. “Countless hours of discussion, sharing ideas on white boards and helping write each other’s codes all enhanced our scientific successes.”

Nittrouer concludes, “Rice’s motto is ‘Unconventional Wisdom’.  When I view the accomplishments of these students, I can’t help but applaud their unconventional generosity, humility, and determination.  These students selflessly helped one another, and thanks to the support here at Rice, there was no lack for opportunity”.

JGR Planets: The solidus and melt productivity of nominally anhydrous Martian mantle constrained by new high pressure-temperature experiments – Implications for crustal production and mantle source evolution

Shuo Ding, Rajdeep Dasgupta, Kyusei Tsuno

 

Abstract: We constrained the solidus of a model Martian composition with low bulk Mg# (molar MgO/(MgO + FeOT) × 100 ~75) and high total alkali (Na2O + K2O = 1.09 wt.%) concentration at 2 to 5 GPa by experiments. Based on the new solidus brackets, we provide a new parameterization of the solidus temperature as a function of pressure of Martian mantle: Ts (°C) = − 5P (GPa)2 + 107P(GPa) + 1,068. The newly constrained solidus of the Lodders and Fegley (1997; https://doi.org/10.1006/icar.1996.5653) model Martian composition (LF composition) is 20 to 90 °C lower than the previous solidus of model Martian mantle with lower total alkali (~0.54 wt.%). The supersolidus experiments yield an average isobaric melt productivity, dF/dT, of 20 ± 6 wt.%/100 °C. We also bracketed the solidi of model Martian mantle compositions with low Mg# (~75) and low alkali (~0.54 wt.%), and with high Mg# (~80) and low alkali (~0.54 wt.%) at a constant pressure of 3 GPa. We find that bulk Mg# enhances the solidus temperature and bulk total alkalis suppress it. A parameterization that estimates the effect of bulk Mg# and total alkalis on peridotite solidus, including Mars and Earth, at 3 GPa can be described as: Ts(°C) = 4.23Mg # − 85(Na2O(wt. %) + K2O(wt. %)) + 1,120. Based on the new solidus parameterizations, 10–40 km more Martian crust would be produced by columnar decompression melting for LF model composition compared to the low Mg#‐low alkali model composition. The quantitative constraints on the solidus shift with Mg# and total alkalis from this study can be used to assess the Martian mantle solidus change through melting and melt extraction over time and the role of mantle heterogeneity in crustal production.

 

Ding, S., Dasgupta, R. & Tsuno, K. (2020). The solidus and melt productivity of nominally anhydrous Martian mantle constrained by new high pressure-temperature experiments – Implications for crustal production and mantle source evolution. Journal of Geophysical Research – Planets 123, e2019JE006078. doi:10.1029/2019JE006078

AGU Monograph: The effect of variable Na/K on CO2 solubility in slab-derived rhyolitic melts

The effect of variable Na/K on CO2 solubility in slab-derived rhyolitic melts

 

Michelle Muth, Megan S. Duncan, Rajdeep Dasgupta

 

Abstract: We conducted high pressure, high temperature experiments to investigate the effect of variable alkali ratio on the CO2‐rich fluid solubility in hydrous rhyolitic melts at sub‐arc depths. Experiments were performed at 3.0 and 1.5 GPa, 1300 °C on rhyolitic compositions similar to low‐degree partial melts of subducted slab lithologies, with fixed total alkalis (Na2O+K2O ~11.5 wt.%, volatile‐free), but Na# (molar Na2O/[Na2O+K2O]) varying from 0.15 to 0.88. In the experimental glasses, total dissolved CO2 (CO2tot.) ranged from 2.14 ± 0.07 to 3.20 ± 0.07 wt.% at 3.0 GPa, and from 0.70 ± 0.02 to 1.19 ± 0.02 wt.% at 1.5 GPa. Experiments showed a general positive correlation between Na# and CO2tot., with the exception of the highest Na# experiment at 1.5 GPa. Carbon was dissolved as molecular CO2 (CO2mol.) and carbonate (CO32‐). As Na# increased, CO2mol./CO2tot. decreased from 0.94 to ~0.00 in the 1.5 GPa experiments and from 0.65 to 0.05 in the 3.0 GPa experiments. Variability in CO2 concentration is larger and more clearly correlated with Na# at 3.0 GPa, indicating that this effect is pressure dependent. Our results show that compositional variability in silicic melts must be considered to accurately place constraints on the limit of CO2 transfer in subduction zones.

 

Muth, M., Duncan, M. S., Dasgupta, R. (2020). The effect of variable Na/K on CO2 solubility in slab-derived rhyolitic melts. In Manning, C., Lin, A., and Mao, W. (Eds.) Carbon in Earth’s Interior, Geophysical Monograph 249, 195-208. doi:10.1002/9781119508229.ch17

Kirsten Siebach’s Reading The Martian Record: Stories of a previously Habitable World

Climate prompts change at Rice