Mineralogical Investigation of Mg-Sulfate at the Canaima Drill Site, Gale Crater, Mars

For the first time on Mars, the crystalline magnesium-sulfate mineral starkeyite (MgSO4‧4H2O) was definitively identified using the CheMin X-ray diffraction instrument at Gale crater. At the Canaima drill site, starkeyite along with amorphous MgSO4‧nH2O are among the “polyhydrated Mg-sulfates” interpreted in orbital reflectance spectra. Mg-sulfates are good climate indicators as they are very responsive to changes in temperature and relative humidity. We hypothesize that, through evaporation, Mg-sulfates formed at the end of brine evolution when ion concentrations became saturated and precipitated on the surface or near sub-surface as either epsomite or meridianiite. These minerals were subsequently dehydrated later to starkeyite and amorphous MgSO4‧nH2O in response to a drier Mars. At Canaima, starkeyite is stable and would form during the warmer Mars summers. Due to very slow kinetics at the low Mars winter temperatures, starkeyite and amorphous MgSO4‧nH2O would be resistant to recrystallize to more hydrous forms and thus likely persist year-round. During the course of analyses, starkeyite transforms into amorphous MgSO4‧nH2O inside the rover body due to the elevated temperature and greatly reduced relative humidity compared to the martian surface at the Canaima drill site. It is possible that crystalline sulfate minerals existed in earlier samples measured by CheMin but altered inside the rover before they could be analyzed. Starkeyite is most likely prevalent in the subsurface, whereas both starkeyite and amorphous MgSO4‧nH2O are likely present on the surface as starkeyite could partially transform into amorphous MgSO4‧nH2O due to direct solar heating. © 2023. The Authors.Open access articleThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Anecdotal to actual: identifying users of learning development to inform future practice

With increasing pressure on universities to ensure their students are graduating with a good honours degree, understanding where Learning Development sits in the university and its impact is arguably becoming more important. The Centre for Learning and Study Support (CLaSS) at De Montfort University, Leicester, has investigated data, collected since 2010, on student engagement with our Learning Development Service. The study aimed to discover the diversity of students availing of learning development, with regards to characteristics such as: gender, ethnicity, disability, age, parental education and module marks. The data presented shows how CLaSS can justifiably engage in university wide discussions about retention and achievement, as well as widening participation agendas. It compares, where possible, who is using CLaSS to the diversity of students within the university. Initial findings are presented, with discussion about how findings have impacted practice, with a particular focus on the attainment gap. From close analysis of the findings which demonstrate a lack of engagement by males with learning development, the paper proposes why this may be the case and offers insight into recent activities to try and reduce the gender gap. Overall, the paper recognises how interpretation of and greater awareness of our user diversity has informed our team strategy and future direction