The Deuterium to Hydrogen Ratio in the Water that Formed the Yellowknife Bay Mudstones in Gale Crater

A suite of isotope ratios of light elements in the present martian atmosphere (13C/12C, 15N/14N, 18O/16O, 38Ar/36Ar, and D/H) are all substantially enriched in the heavy element suggesting atmospheric loss to space over the past billions of years with preferential loss of the lighter isotope from each pair. In situ measurements from MSL's Sample Analysis at Mars (SAM) instrument [e.g. 1,2,3] have considerably refined previous measurements from the Viking mass spectrometers [e.g. 4], from remote spectroscopic observations [e.g. 5,6], and from martian meteorite studies [e.g. 7,8]. The persistence of habitable environments such as the ancient Yellowknife Bay lake recently revealed by measurements from the Curiosity rover [9] depends on the surface temperatures and the duration of an atmosphere thicker than that at present. Current and planned measurements from orbit with the Mars Express and MAVEN missions respectively intend to study the processes of atmospheric escape including solar wind interaction, sputtering, thermal escape, and dissociative recombination, and determine or refine the current rate of atmospheric loss caused by these and other mechanisms. The goal of these programs is to understand the physical processes sufficiently well so that robust extrapolations over the past billions of years can be made D/H is measured by both the Tunable Laser Spectrometer (TLS) and the Quadrupole Mass Spectrometer (QMS) of the SAM suite. to predict the atmospheric and surface conditions on early Mars. However, the study of the history of martian atmospheric evolution will be greatly facilitated if we are able to also directly measure the isotopic composition of volatiles captured in rocks that are representative of the ancient atmosphere. To date, D/H is one of the most promising candidates for this study since water is the most abundant volatile thermally released from the Yellowknife Bay phylosilicates discovered by the SAM and CheMin experiments of MSL and it

Abundance and Isotopic Composition of Gases in the Martian Atmosphere: First Results from the Mars Curiosity Rover

Repeated measurements of the composition of the Mars atmosphere from Curiosity Rover yield a (40)Ar/N2 ratio 1.7 times greater and the (40)Ar/(36)Ar ratio 1.6 times smaller than the Viking Lander values in 1976. The unexpected change in (40)Ar/N2 ratio probably results from different instrument characteristics although we cannot yet rule out some unknown atmospheric process. The new (40)Ar/(36)Ar ratio is more aligned with Martian meteoritic values. Besides Ar and N2 the Sample Analysis at Mars instrument suite on the Curiosity Rover has measured the other principal components of the atmosphere and the isotopes. The resulting volume mixing ratios are: CO2 0.960(+/- 0.007); (40)Ar 0.0193(+/- 0.0001); N2 0.0189(+/- 0.0003); O2 1.45(+/- 0.09) x 10(exp -3); and CO 5.45(+/- 3.62) x 10(exp 4); and the isotopes (40)Ar/(36)Ar 1.9(+/- 0.3) x 10(exp 3), and delta (13)C and delta (18)O from CO2 that are both several tens of per mil more positive than the terrestrial averages. Heavy isotope enrichments support the hypothesis of large atmospheric loss. Moreover, the data are consistent with values measured in Martian meteorites, providing additional strong support for a Martian origin for these rocks

Primordial argon isotope fractionation in the atmosphere of Mars measured by the SAM instrument on Curiosity and implications for atmospheric loss

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102170/1/grl51048.pd

The Search for Nitrates on Mars by the Sample Analysis at Mars (SAM) Instrument

Planetary models suggest that nitrogen was abundant in the early Martian atmosphere as N2 but it was lost by sputtering and photochemical loss to space, impact erosion, and chemical oxidation to nitrates. A nitrogen cycle may exist on Mars where nitrates, produced early in Mars' history, may have been later decomposed back into N2 by the current impact flux. Nitrates are a fundamental source of nitrogen for terrestrial microorganisms, and they have evolved metabolic pathways to perform both oxidation and reduction to drive a complete biological nitrogen cycle. Therefore, the characterization of nitrogen in Martian soils is important to assess habitability of the Martian environment, particularly with respect to the presence of nitrates. The only previous mission that was designed to search for soil nitrates was the Phoenix mission but N-containing species were not detected by TEGA or the MECA WCL. Nitrates have been tentatively identified in Nakhla meteorites, and if nitrogen was oxidized on Mars, this has important implications for the habitability potential of Mars. Here we report the results from the Sample Analysis at Mars (SAM) instrument suite aboard the Curiosity rover during the first year of surface operations in Gale Crater. Samples from the Rocknest aeolian deposit and sedimentary rocks (John Klein) were heated to approx 835degC under helium flow and the evolved gases were analyzed by MS and GC-MS. Two and possibly three peaks may be associated with the release of m/z 30 at temperatures ranging from 180degC to 500degC. M/z 30 has been tentatively identified as NO; other plausible contributions include CH2O and an isotopologue of CO, 12C18O. NO, CH2O, and CO may be reaction products of reagents (MTBSTFA/DMF) carried from Earth for the wet chemical derivatization experiments with SAM and/or derived from indigenous soil nitrogenated organics. Laboratory analyses indicate that it is also possible that <550degC evolved NO is produced via reaction of HCl with nitrates arising from the decomposition of perchlorates. All sources of m/z 30 whether it be martian or terrestrial will be considered and their implications for Mars will be discussed

The Abundance and Hydrogen Isotopic Composition of Water in SNC Meteorites: Implications for Water on Mars

The water in the current martian atmosphere contains ~5 times more deuterium (D) than water on Earth (corresponding to a δD value of ~+4000) resulting from preferential loss of hydrogen relative to deuterium from the martian atmosphere. This thesis places constraints on the D/H of other martian water reservoirs by measuring the D/H of water in hydrous phases within the SNC meteorites, thought to be samples of martian igneous rocks. Results from vacuum extractions of volatiles from bulk SNC samples by stepwise heating show the water yields to decrease and δD values to increase to well above terrestrial values with increasing temperature, indicative of mixing between terrestrial ~+2000 for Shergotty, the most Denriched sample. However, even the highest δD values measured may represent lower limits on the true values due to partial exchange with lighter terrestrial water. D/H and water contents of individual amphibole, biotite and apatite grains in several SNC meteorites were measured using an ion microprobe. The amphiboles contain an order of magnitude less water than previously assumed, suggesting that SNC parent magmas may have been less hydrous than previously proposed. The δD values of the phases range from ~+500 to +4300. The variability and D-enriched nature of these values imply that the primary igneous phases have not retained a martian magmatic water signature. Rather, the high and variable D/H of the water in these phases, like that released at high temperatures from bulk SNC samples, is concluded to result from the interaction of the samples with D-enriched martian crustal fluids after crystallization, probably in an environment similar to terrestrial magmatic hydrothermal systems. The data presented in this thesis represent the first direct evidence for ubiquitous crustal water-igneous rock interaction on another planet. Moreover, the results imply that a large amount of water must have been lost from the martian system since water in the martian crust, in addition to the atmosphere, appears to reflect D-enrichment processes.</p

Seeking Habitable Environments in Our Solar System: Curiosity on Mars

Exploring space is one of humankind’s great endeavors, leading to technological innovation and discoveries that have the potential to answer the most fundamental human questions such as: Are We Alone in the Universe? NASA’s Mars Curiosity Rover landed on Mars in 2012. With its highly advanced suite of cameras and sensors, Mars Curiosity has revealed an ancient Mars that billions of years ago would have been a hospitable habitat for simple life. Although we haven’t yet discovered that life previously existed on Mars, Curiosity continues to provide a window into our neighboring planet’s history that motivates expanded exploration by future robotic spacecraft as well as eventual crewed missions

Hydrogen isotope geochemistry of SNC meteorites

We report the yields and hydrogen isotopic compositions of water extracted by stepwise heating of eight whole-rock SNC meteorites. D/H values are consistent with terrestrial water at low temperatures and increase with temperature to values that far exceed terrestrial. The data are consistent with the water in the samples originating from two sources: a terrestrial component/contaminant, released largely at low temperature, and an extraterrestrial component, released at high temperature. The variation in δD values of the high-temperature hydrogen (∼+250 to +900 for the nakhlites, ∼+1200 to +2100 for the shergottites, and ∼+800 for ALH84001) could represent true variation of the δD of the extra-terrestrial water in the samples, or may reflect varying contributions of the terrestrial endmember, even at high temperature. The high δD values are consistent with a martian origin for the meteorites since the current martian atmosphere contains water with a δD of ∼+4000. The presence of alteration products in at least some of the samples suggests the D-enriched water was probably incorporated into the rocks through interaction at low temperature with aqueous crustal fluids that had exchanged with the martian atmosphere. Chassigny contains water that has terrestrial δD values at all temperatures (with the possible exception of the highest temperature step, with δD up to ∼+50), suggesting contamination of this sample by terrestrial water. Carbon and oxygen isotopic results for CO_2 extracted by stepwise heating are also reported. These data are consistent with formation of carbonates in the SNC meteorites by secondary processes on Mars (from fluids that had exchanged C and O with the atmosphere), perhaps in the same alteration events that formed the D-enriched minerals

UBC Science's 50th Anniversary Lecture – Science : The Gender Dimension

Women remain underrepresented in many fields of science, technology, engineering and mathematics (STEM). Esteemed panelists, planetary scientist and NASA Distinguished Public Service Medal winner Dr. Laurie Leshin, zoologist and MacArthur Genius grant winner Dr. Sally Otto, and Vice President, Response Biomedical Corp and UBC Science Alumna Dr. Barbara Kinnaird-Steen, with our moderator Dr. Simon Peacock, Dean of UBC’s Faculty of Science, as they discuss the STEM gender gap.Science, Faculty ofNon UBCZoology, Department ofUnreviewedFacultyOthe