Abstract_EANA2024-63

Abstract EANA2024-63

TAneZrouft sALt flat dEposits (SAhara Desert): a priority target for a Mars Sample Return mission (AZALEA)

Adel Abdelali (1), Monica Pondrelli (2), Giorgio Gasparotto (1), Youceff Sellam (4), Sakina Khalleff (5), Yelena Caddeo (2), Francesca Mancini (2), Barbara Cavalazzi (1)

(1) Dipartimentio di Scienze Biologiche, Geologiche e Ambientali-BIGEA, Alma Mater Studiorum - Università di Bologna, Bologna, Italy; (2) International Research School of Planetary Science-IRSPS, Università di Chieti-Pescara, Pescara, Italy; (3) Space Research and Planetary Sciences, Physics Institute, University of Bern, Bern, Switzerland; (4) Département des Sciences Biologiques, Université Kasdi Merbah Ouargla, Ouargla, Algeria 

The understanding of Mars planetary evolution and its implication on global changes and the related development of conditions suitable for the development of life are the main objectives for space agencies to plan their exploration for in situ human and robotic missions. From this perspective brines and evaporites are regarded as key exploration targets for the astrobiological exploration of Mars. Mars hosts salt deposits as identified from orbital imagery, including deposits in settings resembling terrestrial evaporitic sabkhas (REF). The key to plan, develop, and perform effective in-situ exploration is to deepen the scientific understanding and optimize the procedures and operational sequences in appropriate planetary field analogues. In this framework, the ‘Tanezrouft salt flat deposits (Sahara Desert): a priority target for a Mars Sample Return mission’ (AZALEA) project aims to perform a detailed study of the Tanezrouft Basin in the context of a simulated MSR-like mission.

Situated along the borders of Algeria and Mali, west of the Hoggar Mountains. The Tanezrouft is considered one of the most arid parts of the Sahara Desert. In the selected area, the stratigraphic succession is the one of the Pharusian chain built during the Pan-African orogeny (600-550 Ma).  Here metamorphic Precambrian formations are unconformbly covered to the north by the Paleozoic sedimentary succession. The Quaternary deposits unconformably on top of this successions consists of alluvial, sabkha, and aeolian deposits, an environmental association very similar to the one observed in several areas on Mars. A systematic sampling of the sabkha deposits was performed to characterize their astrobiological potential (1) and at the same time to standardize a protocol for sampling, storage, and analysis (2). Under this framework, it is essential to define a geological context in order to define the base to compare the planetary field analogues to their potential Martian counterparts because of the different scale of observation of the two settings. The sabkha evaporites appear to postdate the alluvial deposits similarly to what generally observed on Mars.

The detail mapping of alluvial deposits is in progress with the following goals

1. understand whether they were formed in a single phase or reflect different climatic conditions;

2. define the climatic condition(s) during which they were deposited.

This mapping is performed using remote sensing techniques, but ground truth observations were and will be performed to constrain the remote observations and define the lithological suites in the different units to compare them from the results of the spectral observations.