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Phyllosilicates on Mars and implications for early martian climate

Mangold, N.; Bibring, J. -P.; Arvidson, R. E. +6 more

The recent identification of large deposits of sulphates by remote sensing and in situ observations has been considered evidence of the past presence of liquid water on Mars. Here we report the unambiguous detection of diverse phyllosilicates, a family of aqueous alteration products, on the basis of observations by the OMEGA imaging spectrometer o…

Tropical to mid-latitude snow and ice accumulation, flow and glaciation on Mars

Jaumann, R.; Head, J. W.; Neukum, G. +11 more

Images from the Mars Express HRSC (High-Resolution Stereo Camera) of debris aprons at the base of massifs in eastern Hellas reveal numerous concentrically ridged lobate and pitted features and related evidence of extremely ice-rich glacier-like viscous flow and sublimation. Together with new evidence for recent ice-rich rock glaciers at the base o…

Discovery of an aurora on Mars

Bertaux, Jean-Loup; Leblanc, François; Korablev, Oleg +5 more

In the high-latitude regions of Earth, aurorae are the often-spectacular visual manifestation of the interaction between electrically charged particles (electrons, protons or ions) with the neutral upper atmosphere, as they precipitate along magnetic field lines. More generally, auroral emissions in planetary atmospheres ``are those that result fr…

Evidence from the Mars Express High Resolution Stereo Camera for a frozen sea close to Mars' equator

HRSC Co-Investigator Team; Head, James W.; van Gasselt, Stephan +10 more

It is thought that the Cerberus Fossae fissures on Mars were the source of both lava and water floods two to ten million years ago. Evidence for the resulting lava plains has been identified in eastern Elysium, but seas and lakes from these fissures and previous water flooding events were presumed to have evaporated and sublimed away. Here we pres…

Discovery of a flank caldera and very young glacial activity at Hecates Tholus, Mars

HRSC Co-Investigator Team; Head, James W.; Greeley, Ronald +8 more

The majority of volcanic products on Mars are thought to be mafic and effusive. Explosive eruptions of basic to ultrabasic chemistry are expected to be common, but evidence for them is rare and mostly confined to very old surface features. Here we present new image and topographic data from the High Resolution Stereo Camera that reveal previously …

Planetary science: Are there active glaciers on Mars?

Montgomery, David R.; Gillespie, Alan R.; Mushkin, Amit

Planetary science: Are there active glaciers on Mars? (Reply)

Jaumann, R.; Head, J. W.; Neukum, G. +11 more

Gillespie et al. concur with our interpretation that certain lobate equatorial and mid-latitude features on Mars are due to debris-covered glaciers formed largely during past periods of increased spin-axis obliquity, when climate regimes favoured snow and ice accumulation and glacial flow. They suggest that the `hourglass' deposit, dated at more t…