The high-resolution map of Oxia Planum, Mars; the landing site of the ExoMars Rosalind Franklin rover mission

This 1:30,000 scale geological map describes Oxia Planum, Mars, the landing site for the ExoMars Rosalind Franklin rover mission. The map represents our current understanding of bedrock units and their relationships prior to Rosalind Franklin’s exploration of this location. The map details 15 bedrock units organised into 6 groups and 7 textural and surficial units. The bedrock units were identified using visible and near-infrared remote sensing datasets. The objectives of this map are (i) to identify where the most astrobiologically relevant rocks are likely to be found, (ii) to show where hypotheses about their geological context (within Oxia Planum and in the wider geological history of Mars) can be tested, (iii) to inform both the long-term (hundreds of metres to ∼1 km) and the short-term (tens of metres) activity planning for rover exploration, and (iv) to allow the samples analysed by the rover to be interpreted within their regional geological context

In situ fragmentation of lunar blocks and implications for impacts and solar-induced thermal stresses

This study deals with an aspect of blocks observed on many rocky planetary surfaces: in situ fragmentation. Using LROC/NAC images, we characterized the morphology, morphometry and abundance of in-situ fractured blocks observed on the rim of six large impact craters of known emplacement age on the Moon. The relative number of disrupted blocks increases with crater-retention age of surfaces on which blocks are hosted, consistent with fragmentation post-emplacement due to impacts of small meteoroids. The type of break-up morphologies we observe appears to be independent of surface exposure age of the blocks. The inferred flux and size frequency distribution of projectiles responsible for disrupting blocks is consistent with expected lunar impact fluxes. Block fragmentation due to insolation-driven thermal stresses is subordinate to impacts. The possible effects of thermal stresses are evident as meridional cracks, which have preferred orientations in a young block population (~4 Ma), and as loose material (fillet) developing on top of surviving blocks in old populations (>800 Ma)

Preliminary geological map of the AC-H-1 quadrangle- an integrated mapping study usind Dawn spacecraft data

We present a photo-geological map of the “Asari” quadrangle covering the North Pole area of Ceres (66°N-90°N), based on Dawn Framing Camera images and mosaics with a resolution of ~400 m/pixel. The mapping process is supported by a stereo- photogrammetric digital elevation model. We identified few isolated plateaus of up to ~5 km in altitude relative to the datum and topographic depressions interpreted to be highly degraded impact basins. At 85°N/8°E a cone-shaped positive relief is found, few te of kms large. Overall, the entire quadrangle is heavily cratered, and our measurements of crater density (9.8E-04 km-2 for crater diameters >10 km) identify the area as the most cratered on Ceres. This suggest a different geological history of the quadrangle relative to, e.g., the equatorial regions. The morphology of impact craters is characterized by central peaks and mass wasting deposits. We identified a morphologically-fresh mass wasting deposit at 78°N/38°E, 20 km in length, with a lobate margin and striations on its surface. This deposit and the positive relief at 85°N/8°E will be the focus of future investigations when higher spatia resolution images will be acquired by the Dawn Framing Camera. Observations with a spatial resolution of up to 35 m/pixel are planned and will allow photo-geological mapping at higher details. Support by N. Schmedemann, S. Marchi, R. Jaumann, A. Nathue C.A. Raymond, C.T. Russell, and the Dawn Instrument, Operations, and Science Teams is acknowledged

Initial Gelogical Maps of the AC-H-10 Rongo and AC-H-15 Zadeni Quadrangles of Ceres using DAWN spacecraft data

We used geologic mapping applied to Dawn spacecraft data as a tool to understand the geologic history of the Ac-H-10 Rongo and Ac-H-15 Zadeni quadrangles of dwarf planet Ceres. These regions, Rongo and Zadeni, are located between 22°S-22°N and 288°-360°E and 65-90°S and 0°-360°E, respectively. The Rongo Quadrangle hosts a number of features: 1) the southwest portion is dissected by curvilinear structures likely caused by Yalode basin formation; 2) the central part is marked by dome-like constructs up to 100 km across; 3) a peculiar bright, c.4 km tall, conical structure informally known as the ‘pyramid’; 4) impact craters of various diameters appear moderately to highly degraded or are partially buried; and 5) bright material is primarily exposed in the central portion and often associated with craters. Rongo crater (68 km across) exhibits a central peak and scalloped walls indicative of its degraded appearance. The Zadeni Quadrangle is characterised by impact craters up to 130 km in diameter of which Zadeni crater is the largest. Impact craters across all sizes exhibit fresh to highly degraded morphologies or are partially buried. Many craters developed central peaks. Inter-crater plains are generally hummocky with isolated regions of smooth-textured surfaces. The south pole area (85-90°S) is poorly illuminated and may host a large impact structure. Upcoming work includes compositional assessment of surface units utilising FC colour images and VIR spectral data and establishment of relative and absolute stratigraphy using crater-based dating techniques

DAWN mission final high resolution global geolgic map of Ceres

A 1:4M global geologic map of dwarf planet (1) Ceres was completed by the science team from NASAs Dawn mission, derived from images obtained during the Low Altitude Mapping Orbit (LAMO, 35 m/px). The map was published on the cover of Icarus, volume 316, December 2018 issue, along with a series of papers describing the geology within Ceres quadrangles. In this abstract we present the final map (Figure 1) and summarize our findings

The vanishing cryovolcanoes of Ceres

Ahuna Mons is a 4 km tall mountain on Ceres interpreted as a geologically young cryovolcanic dome. Other possible cryovolcanic features are more ambiguous, implying that cryovolcanism is only a recent phenomenon or that other cryovolcanic structures have been modified beyond easy identification. We test the hypothesis that Cerean cryovolcanic domes viscously relax, precluding ancient domes from recognition. We use numerical models to predict flow velocities of Ahuna Mons to be 10-500 m/Myr, depending upon assumptions about ice content, rheology, grain size, and thermal parameters. Slower flow rates in this range are sufficiently fast to induce extensive relaxation of cryovolcanic structures over 10(8)-10(9) years, but gradual enough for Ahuna Mons to remain identifiable today. Positive topographic features, including a tholus underlying Ahuna Mons, may represent relaxed cryovolcanic structures. A composition for Ahuna Mons of >40% ice explains the observed distribution of cryovolcanic structures because viscous relaxation renders old cryovolcanoes unrecognizable.6 month embargo; First published: 10 February 2017This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Final DAWN LAM-based global geologic map of Ceres

A 1:4M global geologic map of dwarf planet (1) Ceres was completed by the science team from NASAs Dawn mission, derived from images obtained during the Low Altitude Mapping Orbit (LAMO, 35 m/px). The map was published on the cover of Icarus, volume 316, December 2018 issue, along with a series of papers describing the geology within Ceres quadrangles. In this abstract we present the final map (Figure 1) and summarize our findings