Glaciovolcanic hydrothermal environments in Iceland and implications for their detection on Mars

Volcanism has been a dominant process on Mars, along with a pervasive global cryosphere. Therefore, the interaction between these two is considered likely. Terrestrial glaciovolcanism produces distinctive lithologies and alteration terrains, as well as hydrothermal environments that can be inhabited by microorganisms. Here, we provide a framework for identifying evidence of such glaciovolcanic environments during future Mars exploration, and provide a descriptive reference for active hydrothermal environments to be utilised for future astrobiological studies. Remote sensing data were combined with field observations and sample analysis that included X-ray diffraction, Raman spectroscopy, thin section petrography, scanning electron microscopy, electron dispersive spectrometer analysis, and dissolved water chemistry to characterise samples from two areas of basaltic glaciovolcanism: Askja and Kverkfjöll volcanoes in Iceland. The glaciovolcanic terrain between these volcanoes is characterised by subglacially-erupted fissure swarm ridges, which have since been modified by multiple glacial outburst floods. Active hydrothermal environments at Kverkfjöll include hot springs, anoxic pools, glacial meltwater lakes, and sulfur- and iron- depositing fumaroles, all situated within ice-bound geothermal fields. Temperatures range from 0 °C - 94.4 °C, and aqueous environments are acidic - neutral (pH 2 - 7.5) and sulfate-dominated. Mineralogy of sediments, mineral crusts, and secondary deposits within basalts suggest two types of hydrothermal alteration: a low-temperature ( 120 °C) assemblage signified by zeolite (heulandite) and quartz. These mineral assemblages are consistent with those identified at the Martian surface. In-situ and laboratory VNIR (440 – 1000 nm) reflectance spectra representative of Mars rover multispectral imaging show sediment spectral profiles to be influenced by Fe2 +/3 + - bearing minerals, regardless of their dominant bulk mineralogy. Characterising these terrestrial glaciovolcanic deposits can help identify similar processes on Mars, as well as identifying palaeoenvironments that may once have supported and preserved life

Phosphorus: a Case for Mineral-Organic Reactions in Prebiotic Chemistry

The ubiquity of phosphorus (P) in modern biochemistry suggests that P may have participated in prebiotic chemistry prior to the emergence of life. Of the major biogenic elements, phosphorus alone lacks a substantial volatile phase and its ultimate source therefore had to have been a mineral. However, as most native P minerals are chemically un-reactive within the temperature-pressure-pH regimes of contemporary life, it begs the question as to whether the most primitive early living systems on earth had access to a more chemically reactive P-mineral inventory. The meteoritic mineral schreibersite has been proposed as an important source of reactive P on the early earth. The chemistry of schreibersite as a P source is summarized and reviewed here. Recent work has also shown that reduced oxidation state P compounds were present on the early earth; these compounds lend credence to the relevance of schreibersite as a prebiotic mineral. Ultimately, schreibersite will oxidize to phosphate, but several high-energy P intermediates may have provided the reactive material necessary for incorporating P into prebiotic molecules

Raman spectra of biomarkers of relevance to analytical astrobiological exploration: hopanoids, sterols and steranes

The aim of this work is to investigate the viability and potential of three groups of organic compounds as biomarkers in a future robotic analytical exploration of Mars. The three compounds have been identified as suitable candidates for potential biomarkers for extant or extinct life from the terrestrial fossil record. The three groups of compound were all similar in structure, being either tetra- or penta-cyclic compounds. The limits of detection for a sample were also tested to estimate what concentrations it would still be amenable to Raman spectroscopic investigation. This was investigated using both solid mixtures and liquid solutions. The spectra of these compounds are characterised so that they can be added to the Raman database for future Mars missions. This involved identifying functional group characteristics, assigning peaks for each individual sample and characteristic features which would categorise the samples. © 2010 Elsevier B.V. All rights reserved

Objective analysis of envelope curves for peak floods of European and Mediterranean flash floods

Flash floods rank highly among natural disasters in terms of number of affected people and number of fatalities. This paper analyzes the scaling of the highest flash flood peaks at multiple spatial scales for different hydro-climatic regions in Europe and in the Mediterranean.The analysis is based on an integrated, high-resolution dataset of discharges concerning a number of high-intensity flash floods that occurred in these regions from 1991 to 2015. Quantile regression has permitted to define regional envelope curves of unit peak discharge versus drainage basin area, which summarize the current bound to extreme flash floods in a given region. Mean and standard error of the envelope curves’ parameters are objectively derived, permitting to explore the similarities in the slopes of the regional envelope curves. Results indicate that the exponent of the envelope curves shows almost negligible variations among climatic region whereas the multiplier depends on the climatic regions

Citizen science for hydrological risk reduction and resilience building

In disaster risk management (DRM), an emerging shift has been noted from broad-scale, top-down assessments toward more participatory, community-based, bottom-up approaches. Arguably, nonscientist local stakeholders have always played an important role in knowledge risk management and resilience building within a hydrological context, such as flood response and drought alleviation. However, rapidly developing information and communication technologies such as the Internet, smartphones, and social media have already demonstrated their sizeable potential to make knowledge creation more multidirectional, decentralized, diverse, and inclusive. Combined with technologies for robust and low-cost sensor networks, a ‘citizen science’ approach has recently emerged as a promising direction in the provision of extensive, real-time information for risk management. Such projects work best when there is community buy-in, when their purpose(s) are clearly defined at the outset, and when the motivations and skillsets of all participants and stakeholders are well understood. They have great potential to enhance knowledge creation, not only for data collection, but also for analysis or interpretation. In addition, they can serve as a means of educating and empowering communities and stakeholders that are bypassed by more traditional knowledge generation processes. Here, we review the state-of-the-art of citizen science within the context of hydrological risk reduction and resilience building. Particularly when embedded within a polycentric approach toward risk governance, we argue that citizen science could complement more traditional knowledge generation practices, and also enhance innovation, adaptation, multidirectional information provision, risk management, and local resilience building