Martian dunes indicative of wind regime shift in line with end of ice age

Abstract

Orbital observations suggest that Mars underwent a recent ‘ice age’ (roughly 0.4–2.1 million years ago), during which a latitude-dependent ice-dust mantle (LDM)1,2 was emplaced. A subsequent decrease in obliquity amplitude resulted in the emergence of an ‘interglacial period’1,3 during which the lowermost latitude LDM ice4–6 was etched and removed, returning it to the polar cap. These observations are consistent with polar cap stratigraphy1,7, but lower- to mid-latitude in situ surface observations in support of a glacial–interglacial transition that can be reconciled with mesoscale and global atmospheric circulation models8 is lacking. Here we present a suite of measurements obtained by the Zhurong rover during its traverse across the southern LDM region in Utopia Planitia, Mars. We find evidence for a stratigraphic sequence involving initial barchan dune formation, indicative of north-easterly winds, cementation of dune sediments, followed by their erosion by north-westerly winds, eroding the barchan dunes and producing distinctive longitudinal dunes, with the transition in wind regime consistent with the end of the ice age. The results are compatible with the Martian polar stratigraphic record and will help improve our understanding of the ancient climate history of Mars9.

Alkali Trace Elements Observed by MarSCoDe LIBS at Zhurong Landing Site on Mars: Quantitative Analysis and Its Geological Implications

“…As mentioned above, both MarSCoDe LIBS and SWIR spectra imply the recent aqueous activity at the Zhurong landing site (e.g., ∼2.1–0.4 Ma, J. Liu et al., 2023). However, there are two interpretations regarding how the recent aqueous activity occurred: evaporation of groundwater (Y. Liu et al., 2022; J. Wang et al., 2023); saline water from thawed frost/snow (Qin et al., 2023) or water vapor cycling (Y. Y. S. Zhao et al., 2023) on the surface.…”

“…The absorption features of hydrated silica or hydrated sulfates were identified in the SWIR spectra of rocks (Y. Liu et al., 2022). The dunes also exhibit spectral characteristics of hydrous minerals: hydrated sulfates, hydrated silica, trivalent iron oxide minerals, or chlorides (J. Liu et al., 2023; Qin et al., 2023); hydrated sulfates or Al‐phyllosilicates, more likely hydrated sulfates (J. Wang et al., 2023).…”

“…Along the Zhurong traverse, scattered rocks of various sizes are dispersed on the Martian soil (Figure S7 in Supporting Information ). The bright barchans and dark longitudinal dunes in the Zhurong landing site (Figure S7 in Supporting Information ) formed through the aeolian processes and were not influenced by local topography (J. Liu et al., 2023). The non‐ND scientific targets are classified into three categories: Rock (R), Soil (S), and Dune (D) (Figure 2).…”

China's top 10 breakthroughs in science and technology in 2023

“…Later analysis provided wind direction, terrain evolution and other information about the rover's landing area. Evidence showed that the landing area may have experienced two major climate periods with distinct directions of wind [ 3 ]. This finding is consistent with ice records from mid-to-high latitude regions on Mars.…”