Is the Xanadu region on Titan an impact basin?

Post by Dr. Mirjam Langhans, GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Germany.

The surface of Titan, Saturn’s largest moon, is subject of great geologic interest, particularly since the arrival of Cassini/Huygens mission in the Saturnian System. Titan’s largest distinct and highly reflective surface feature, named Xanadu, is located close to the equator. The image depicts Xanadu in full extension with a rich diversity of geologic landforms, such as fluvial valleys, mountain ridges and impact craters. Despite the high volume of image data in this region, the geologic history behind Xanadu remains enigmatic to this day.

Geomorphologic map of Xanadu. Data: Cassini SAR data, source: (http://pds-imaging.jpl.nasa.gov/portal/cassini_mission.html). background: Cassini-ISS, source: (http://pds-imaging.jpl.nasa.gov/portal/cassini_mission.html). Inner and outer boundary of the Xanadu Circular Feature (XCF) are highlighted at Western Xanadu (black lines, according to Brown et al. (2011)). Green dots: impact craters listed in Wood et al. (2010) and Neish & Lorenz (2012), red dots: potential impact craters. Fluvial channels are delineated in blue. Dark green: lineations seen in mountain ranges, from Radebaugh et al. (2011). Light green: lineations in mountain ranges (Langhans et al. 2013).

Geomorphologic map of Xanadu. Data: Cassini SAR data, source: (http://pds-imaging.jpl.nasa.gov/portal/cassini_mission.html). background: Cassini-ISS, source: (http://pds-imaging.jpl.nasa.gov/portal/cassini_mission.html). Inner and outer boundary of the Xanadu Circular Feature (XCF) are highlighted at Western Xanadu (black lines, according to Brown et al. (2011)). Green dots: impact craters listed in Wood et al. (2010) and Neish & Lorenz (2012), red dots: potential impact craters. Fluvial channels are delineated in blue. Dark green: lineations seen in mountain ranges, from Radebaugh et al. (2011). Light green: lineations in mountain ranges (Langhans et al. 2013).

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Geomorphic activity on asteroid Vesta

Post by Prof. Dr. Ralf Jaumann and Dr. Mary C. Bourke,

German Aerospace Center, Berlin, Germany. 

Department of Geography, Trinity College Dublin, Ireland.

The NASA Dawn spacecraft was launched in September 2007 to characterize the conditions and processes of the solar system’s earliest epoch by investigating in detail two of the largest protoplanets remaining intact since their formation. Ceres and Vesta reside in the extensive zone between Mars and Jupiter together with many other smaller bodies, called the asteroid belt. Each has followed a very different evolutionary path constrained by the diversity of processes that operated during the first few million years of solar system evolution. The Dawn mission entered orbit around Vesta on 16 July 2011 for a one-year exploration and left orbit on 5 September 2012 heading towards Ceres.

Image A. A composite digital terrain model, and high resolution albedo mosaic and imbedded color channels of three cratres on the surface of Vesta. The image is composed of many individual photographs taken between October and December 2011 by Dawn’s framing camera during the high-altitude mapping orbit, at about 680 kilometers above Vesta’s surface. The image is centered on ~ 13° north latitude and ~ 195° eastern longitude. South is to the top of the image. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

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Fluvial flow triggered by impact events on Mars

Post by Andrea Jones, Lunar and Planetary Institute/NASA Goddard Space Flight Center

 In memory of our dear friend and colleague Dr. Elisabetta (Betty) Pierazzo

Hale crater is a 125×150 km impact crater located near the intersection of Uzboi Vallis and the northern rim of Argyre basin on Mars, at 35.7ºS, 323.6ºE. Hale is an unusual crater on Mars because it is modified by fluvial channels. The channels originate from the outer edges of Hale’s ejecta and extend as far as 460 km from the crater rim (Image 1). They are upto a few kilometers wide, exhibit a braided planform (Image 2), and had sufficient stream power to incise and transport the crater ejecta. Most of the channels are found to the south-southwest of Hale crater, on the northern slope of Argyre basin (Image 3).

Image 1

Image 1: Channels in the southeastern ejecta of Hale crater, Mars in a THEMIS daytime-infrared mosaic. The channels were likely carved with water mobilized by the Hale-forming impact event. White box is location of Image 2. North is up in all images.

Image 2

Image 2: Detailed view of fluvial channel flowing through crater ejecta. CTX image
Location is shown in Image 1.

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Impact Craters on Earth and Mars: Monturaqui and Bonneville

Post by Nathalie Cabrol and the High Lakes Science Expedition.

Impact processes are fundamental in the creation of planets, the modification of their landscape, and for Earth, in the evolution of life. However, unlike the other planets of our solar system, Earth has not kept a large record of its impact history. Plate tectonic and erosional processes have erased most of them with time. Small impact craters, in particular, are difficult to preserve but there are still a few left, including the Monturaqui impact crater (23°56’S/68°17’W) located in the Atacama Desert in Chile.

Maturaqui Crater, Chile, Earth

Image 1: Monturaqui impact crater in the Atacama Desert of Chile. Credit: Planetary Spherules Project, Nathalie A. Cabrol, NASA Ames/SETI CSC.

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Mars’s Moon Phobos

Post by Dr William Hartmann

 

The image is of Mars’s 27 x 19 km satellite, Phobos. It hints at many mysteries that await us there. The surface (contrary to the appearance of this well-exposed image) is dark black, probably similar to carbonaceous asteroids, but the exact composition and spectral properties are still uncertain (due partly to scattered reddish light from Mars). Spectra show the surface soil lacks any water, but that soil has been blasted off and recycled through dust belts circling Mars, and then re-accreted onto Phobos. This process likely removes any initial water from the dust, so we can’t be sure whether the surface represents the interior material.

Medusae Fossae Formation on Mars

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Landslide deposits on Mars

Posted by Bill Hartmann, Planetary Science Institute, Tucson, Arizona, USA.

(Re-posted from IAG Image of the month, March 2007)

This high-resolution MGS MOC image shows overlapping landslide deposits at the foot of the wall in the Ganges region of the Valles Marineris canyon complex on Mars. (more…)

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