20-EPN2-121: Constraining the movement of groundwater and fluid expulsion within playa environments on Mars
Visit by Gene Schmidt, Università degli Studi Roma Tre (Italy) and Erica Luzzi, Jacobs University (Germany) to TA1.5 Makgadikgadi Salt Pans (Botswana). Dates of visit: 20-27 October 2021
Across the surface of Mars there is evidence of past lacustrine and evaporitic environments found within basins and craters, where often layered sedimentary deposits and hydrated minerals are observed. However, the intensity, duration and precise phases of water cycle activity during this period remain unresolved. Although several geological processes and locations on Earth have been previously proposed as examples to describe these deposits on Mars, we lack a strong visualisation of what water activity might have looked like during evaportic stages within basins and craters. The Makgadikgadi Salt Pans of Botswana, where once the Makgadikgadi Lake existed, is a present evaporitic environment rich in hydrated minerals and water activity. It is a depression located at the southwestern end of a northeast-southwest set of graben. Faults have been previously proposed to have been pathways for groundwater to enter basins and craters on Mars, which then contributed to both the deposition and alteration of the sedimentary deposits. Thus, imaging the subsurface of a similar environment on Earth can help us to better understand how water processes on Mars might have continued as the Martian global climate became drier.
By using the already established locations of the faults to the north of the pans, we used remote sensing techniques to trace the best location of the faults underneath the pans (Figures 1 and 2). We then used electrical resistivity surveys to image 70 – 150 m of the pans’ subsurface where the faults were deemed most likely to occur. This work allows us to better understand the possibilities of what the underlying lithology of rocks within filled basins and craters might look like. Furthermore, it demonstrates the scientific importance of future missions to employ subsurface imaging techniques on Mars.
From 29 September – 6 October 2021, researchers Daniel Toledo and Victor Apestigue (Instituto Nacional de Técnica Aeroespacial (INTA), Spain) were funded by the Europlanet 2024 Research Infrastructure (RI) Transnational Access (TA) programme to visit the Makgadikgadi Salt Pans in Botsawana. The trip was led by Fulvio Franchi (Botswana International University of Science and Technology (BIUST)) who is responsible for the Botswana Planetary Field Analogue for Europlanet 2024 RI. Ignacio Arruego, Javier Martinez-Oter and Felipe Serrano (INTA) also participated in the field trip.In this guest post, Daniel Toledo reports on the field trip.
The main goal of the field campaign in the Makgadikgadi Salts Pans was to study how dust is lifted into the air. For our investigation, we used the spare units of the Radiation and Dust Sensor (RDS) from the NASA Mars 2020 mission and the Sun Irradiance Sensor (SIS) from the ExoMars 2022 mission (see Figure 1), which are designed to study dust carried in the atmosphere of Mars by measuring how sunlight is scattered by the dust particles.
In addition to giving information about the properties of airbourne dust, these instruments are also sensitive to the presence of dust devils – swirling columns of sand and dust that are a common feature of desert areas on Mars and on Earth. RDS and SIS can detect the changes over time in the sky brightness produced by a dust devil, and this offers a unique opportunity for monitoring and studying such events during the Mars 2020 and ExoMars 2022 missions. However, to be able to characterise and interpret dust devil observations on Mars, we first need to understand how dust devils affect SIS and RDS signals by thorough testing and evaluation of the instruments in Mars-like conditions on Earth.
To achieve this goal, we planned a field campaign from 29 September to 6 October in the southern part of Makgadikgadi Salt Pans (see Figure 3), in the Pan near Mopipi town. This location is characterised by frequent dust devil events and conditions that promote the lifting of high levels of aerosols (dust and particles) into the atmosphere.
Each day of the campaign, we set up RDS and SIS at two different locations from sunrise to sunset, separated by about 25 m, along with:
Two cameras to record panoramic videos during the campaign period.
A Vaisala weather station to perform measurements of pressure, wind direction and intensity, temperature and relative humidity.
A ZEN radiometer to measure how much light was absorbed by the dust at different wavelengths.
The objective of having the two main instruments at two different locations was observe the dust lifting events from different perspectives.
During the campaign, we observed a large number of dust devils (many more than 10) and dust lifting events produced by wind gusts (over 10). For each dust lifting, we recorded the dust devil distance, the size, duration and direction. To do this, we marked out concentric circles with radii of 25, 50, 75, 100, 125 and 150 m on the ground. This information along with the videos made by the cameras, helped us to establish the amount of dust lifted by the dust devil as well as their distances from the instruments. All the data collected for each event was key to establish the RDS and SIS capabilities for dust lifting characterisation on Mars.
The first two days of the campaign were characterised by high dust-loading conditions and frequent formations of dust lifting events produced by dust devils or wind gusts. During these two days, each dust lifting event registered by the cameras was also detected by RDS and SIS, with signals showing a sharp peak at the time when the event passed within the sensors field of view. Preliminary analysis suggests that we can infer from RDS and SIS signals the difference between dust lifting events produced by dust devils and those produced by wind gusts – an important result for the observations on Mars.
The third day of campaign had to be cancelled due to rain. This resulted in a lower dust-loading conditions in the following days, and thus the amount of dust lifted by vortices or wind gusts was smaller compared to the first two days.
Upon return to BIUST in Palapye on 6 October, we held a seminar for staff and students titled Atmospheric science on Mars: from Earth analogues to future planetary networks.
In summary, the campaign was a complete success. Our observations have demonstrated the capability of the RDS and SIS sensors to detect and characterise dust devils on Mars. The analysis of the signals along with the information acquired by the other instruments will allow us to quantitatively establish the sensors limit of detection. In addition, the rainy episode offered us the chance to study dust lifting events in different aerosol loading conditions.
20-EPN2-046: Characterising dust lifting events using the ground-based Mars-2020-RDS and ExoMars-2022-SIS radiometers
Visit by Daniel Toledo, INTA (Spain) to TA1.5 AU Makgadikgadi Salt Pans (Botswana). Dates of visit: 29 September – 06 October 2021
On Mars, the airborne dust is a critical factor that drives the weather and climate of the planet. Dust devils are thought to account for the ~50 % of the total dust budget, and they represent a continuous source of dust, present even outside the dust storms period. For these reasons they have been proposed as the main mechanism able to sustain the observed dust haze of the martian atmosphere. However, additional dust devil surveys covering long diurnal periods are needed to place quantitative constraints on the cycles of these events. In this regard, the present and future observations of the Radiation and Dust Sensor (RDS) and the Sun Irradiance Sensor (SIS), which are part of NASA Mars 2020 and ESA/Roscosmos ExoMars 2022 missions, offer a unique opportunity to monitoring dust devils at high temporal resolution from sunrise to sunset, and with an excellent spatial coverage.
The main goal of the field campaign in the Makgadikgadi Salts Pans (20-EPN2-065) was to study dust lifting events using the spare units of RDS and SIS. During the campaign (29 Sept to 6 Oct 2021), a large number of dust devils (>10) and dust lifting events produced by wind gusts (>10) were observed by RDS and SIS sensors. For each case, information on distance, size, temporal duration and direction was registered. This information along with observations made by other instruments (e.g. wind speed and direction), have allowed us to study the potential RDS and SIS capabilities for dust lifting characterisation on Mars.
Glacial systems are interesting for studying habitability and limits of life. They are extreme environments where indigenous microorganisms may survive prolonged exposure to sub-zero temperatures and background radiation for geological timescales. Glaciers and the surrounding cryo-environments (permafrost, glacial lakes, or melting streams) arise as relevant scenarios for studying the development of functional microbial cryo-ecosystems and may have implications in the search for past or extant life in icy worlds beyond the Earth. In the Solar System, Europa and Enceladus have been recognized as the icy worlds with highest likelihood to harbor life, largely because liquid water could be in contact with rocks. Both satellites are believed to contain a global ocean of salty water under a rigid icy crust that would provide the scenario for an interaction between briny water and rocks, and the conditions for life to arise.
The permanent Greenland Ice Sheet (GrIS) represents a possible analog of such icy worlds, constituting an important long-term repository of psychrophilic microorganisms. Around the GrIS, different formations such as glacial lakes, permafrost, or further peat soils represent diverse degree of succession upon the influence of the GrIS and its thermal destabilisation.
We propose investigating molecular and isotopic lipid biomarkers of microorganisms inhabiting different cryo-ecosystems at and around the GrIS to obtain clues of a potential life development on analogous extraterrestrial cold environments (ice sheet), and learning how ecosystems evolves (biological succession) when the ice cover retreats and gets exposed to the atmosphere (glacier-melting streams, bedrock-erosion sediments, lake sediments, glacial soils).
Report Summary: The aim of this field campaign was to investigate the dynamics of aeolian mineral dust activity and organic carbon burial in western Greenland. Dust is an important component of the global climate system, and investigating its mobilisation, transport and deposition can reveal important information about regional climate and environmental development during the Holocene. Carbon burial in permafrost is one of the main mechanisms by which carbon is sequestered from the atmosphere, and may be linked to dust activity in high latitudes. The work focused on the area between the Greenland Ice Sheet margin and Kangerlussuaq, which represents a range of environmental conditions depending on distance from the ice sheet. We collected modern analogue samples of terrestrial windblown dust (loess) deposits to test and compare the performance of optically stimulated luminescence and radiocarbon dating. These samples were taken at a high-resolution from the surface of the deposits and thus represent recent aeolian activity. Furthermore, we targeted aeolian deposits containing palaeosol layers to be able to independently compare radiocarbon and luminescence ages, and to identify climate phases which were favourable for soil formation and carbon burial. In addition to purely aeolian sediments, peat bogs were also sampled.
These highly organic deposits complement the nearly purely minerogenic loess deposits because they effectively capture and preserve fine-grained wind-blown sediments. Further analysis of these samples and the use of different climate and carbon burial proxies will reveal important details of the regional climate history, dust-carbon burial dynamics, and provide insights into ice-proximal wind dynamics.
Report Summary: The Isunguata Sermia and Russell glaciers represent optimal analogues for the study of deformation in glacial environments and their comparison with deformation that affects the icy satellites of Jupiter and Saturn. The aim of UPSIDES project concerns the relation of tectonic structures from the outcrop to the regional scale with multi-scalar investigation which can provide significant support for planetary analysis. The collection of field data has been significant to find scaling laws between tectonic structures in glaciers and in icy satellite surfaces, and the behaviour at depth of their tectonic structures.
The successful fieldwork in the Kangerlussuaq area enabled the identification of tectonic structures in representative areas of the Isunguata Sermia (southern margin) and Russell glaciers (northern margin and terminus). More than 250 data have been collected from 31 field measurement stations including high dip- and low dip-structures, originated by different stress fields caused by the westward flow of both glaciers. We recognized high dip-extensional fractures approximately E-W and NE-SW trending at the Russell glacier. On the other hand, NNW-SSE trending fractures and low-angle faults, such as compressional thrusts/shear planes, have been detected at the Isunguata Sermia. From satellite imagery and aerial photos, we detected consistent structural orientations with the structures identified in outcrop. A similar correlation will be applied to the structures recognised by remote sensing on the icy satellites. Additionally, at the outcrop scale we identified structures acting as preferential way of fluid circulation. We performed measurements also in rock outcrops near the glacier to understand the relationship between bedrock morpho-tectonics and ice drainage that in turn control the measured glacial deformation.
20-EPN-017: LITRASV – Life in TRAvertine-Sinter Veins: a possible key to recognize extra-terrestrial life in tectonically-driven depositional systems.
Visit by Enrico Capezzuoli, University of Florence and Andrea Brogi, University of Bari (Italy) to TA1 – Iceland Field Sites, MATIS Dates of visit: 04-10 July 2021
Report Summary: Detailed study of travertine and sinter depositional systems and related feeder conduits (veins) in cold desertic setting (Lýsuhóll and Hveravellir sites- Iceland), as possible repository of subsurface life to be observed in extra-terrestrial setting. The performed field activity allows reconstruction of the structural control in these sinter/travertine depositional systems, with stratigraphic-sedimentological characterisation of the travertine-sinter lithofacies. 16 travertine/sinter samples were collected from the two sites, together with the basic physical characterization of the thermal springs (T, pH, Cond). Due to the local conditions, all the collected samples derive from fossil/inactive systems (veins and crusts samples). Among these, one sample derives from a sinter vein recognized in the Lýsuhóll site, while all other derive from fossil vents or close surroundings.
Samples returned to Italy for future petrographic and geochemical characterization in order to detect and define possible organic presence in such an extreme environment.