Namiba Titan Analogs Trip 2013

Ever since we discovered dunes on Titan, whose nature was made apparent by comparison with a space shuttle picture of the Namib sand sea whose dunes are just the same size and shape as Titan's, I've wanted to visit. Together with some Titan colleagues ( Prof. Jani Radebaugh of BYU, Prof. Jason Barnes of U.Idaho, and Prof. Alex Hayes of Cornell , we eventually got the opportunity to go (organizing logistics and permits took many months). Further images by Jani here
01_map Starting in Windhoek, we drove (with a ridiculous amount of gear packed into two VW Polos) via Swakopmund to Gobabeb. From there we made two 4x4 day trips into the north part of the sand sea, getting as far as Tsondab Vlei. Then back to Windhoek via Swakopmund. In Windhoek we met up with Roy Miller, former Director of the Geological Survey, who guided us (with Vernon Swanepoel of Frantic Naturalist tours) down to the mining town of Rosh Pinah, some 900km to the south. From there we ventured into the Sperrgebeit, the Forbidden Zone, a designated diamond mining area and now a national park, to spend two days surveying the Roter Kamm impact stucture. From there north to Aus (a town set up as a POW camp for German prisoners in 1915) and thence to the dunes at Sossuvlei and back to Windhoek. All in all about 2500km in 12 days. 02_gibeonDSCN0037 Windhoek is a very manageably small city, with a notable German influence (decent beer for a start!). It was a German colony until 1915, when South Africa took control. Because of that there is a bit of British influence too (e.g. you drive on the left). While best-known to geomorphologists for its sand dunes, there is a bonus planetary connection. There is a striking display of a dozen or so masses of the Gibeon meteorite (a large iron) in the mall. Photo:Jani 03_gobabebDSCN0136 The Gobabeb Research and Training Center , right at the edge of the sand sea, and just south of the Tropic of Capricorn, was a great base for our dune survey operations. They are self-contained with wind and solar power, internet access etc., but are right at the edge of the sand sea.
04_GPR_DSCN0196 Among our dune operations were ground-penetrating radar surveys. Here Karl Arnold (a student at BYU) drags the 250 MHz GPR antenna, while Clayton Chandler (another student) monitors the data quality. Their advisor, Prof Radebaugh supervises alongside. This dune is transverse to the main set, a transitional feature sometimes referred to as a 'raked' dune. 05_swakopkite_high Returning from Gobabeb, we visited the corridor of dunes between Walvis Bay and Swakopmund. With the kite camera I captured these barchans spalling off the linears. The Atlantic Ocean is just visible in the background. 06_P1010124_jani We took a scenic flight over the sand sea, which was an excellent way to see and understand the different dune types. A number of outfits run affordable flights from Swakopmund, using high-winged Cessna 210s that give you a great view. Here I gaze over the near-endless linears in the main part of the sand sea. Photo by Jani.
07_DSCN0301 Probably one of the most striking impressions was of the role of the (usually dry) Kuiseb river, which sharply truncates the dunes at the northern edge of the sand sea. We suspect that analogous (but unseen, and usually dry) rivers may define the edges of many dunefields on Titan, which comprise the same type of dune (linear/longitudinal) as here. 08_DSCN0370 Another feature seen on Titan is the deviation of linear dunes by inselbergs ('island mountains') as here. The horizontal distance out to which the mountain influences the dune pattern is remarkable, presumably something to do with the thickness of the planetary boundary layer (which determines the ultimate height of dunes, and appears to be similar in the Namib and on Titan). 09_P8112003 We indulged in an afternoon of R&R, exploring the trafficability of dunes and thus the suitability of rovers for Titan exploration. L-R: Jani, Clayton, Alex Hayes, myself, Jason Barnes, Karl.
10_P1010437_jani After getting laundry done, 5 hours drive back to Windhoek, meeting with the present director of the Geological Survey to get our special Sperrgebeit permits, some extensive loading operations into a pickup truck and Roy Miller's custom Land Cruiser kitted out for the field with 2 spares, water tanks, rooftop tent etc., we drove south for about 9 hours to Rosh Pinah (site of a large Zinc mine) and then a couple of hours cross-country to the Roter Kamm impact crater. It was in fact quite cold in the evenings, here Karl, Alex, Jason and I watch as Vernon prepares dinner in the field. Photo by Jani. 11_GOPR0758 The 2.5km crater is some 4 million years old, but reasonably well-preserved for its age because there is little rainfall. It is, however, substantially filled-in with aeolian sand, and some dunes skirt the rim and cross the crater in a couple of places, an arrangement we also see on Titan. Comparing spaceborne radar images with conditions in the field, we determined that the vegetation (even relatively sparse as it is) dominates the radar return - in particular, the succulent Euphorbia bushes may have a branch spacing that acts as a resonant reflector. Here I fly the kitecam to get a perspective intermediate between that from orbit and that on the ground. 12_Roterkammperfect In fact, the crater is large enough that it wasnt possible to fit it all in from the rim. Even with all 1000 feet of line out, I had to come a bit downwind of the rim to get the camera far enough away to catch the whole structure, but perseverance (and a stiff breeze) eventually gave me the shot I wanted. The shallow depth of the crater is evident here.
13_sossusvleidunes The giant dunes, which take on a pyramidal form here where the ephemeral Tsauchab river occasionally truncates the linear dunes, are among the highest in the world (although benefit from being built on an earlier generation of the sand sea, apparently). 14_IMG_2051_jason Me on the dune next to dead vlei, the clay pan where the lifeless tree skeletons show that past conditions have sometimes allowed trees to grow. The close juxtaposition of dunes with very flat pan surface (Afrikaans: 'vlei') is something that radar data on Titan has been hinting at, but here is very evident. Photo: Jason. 15_SosussVlei_Group1_alex Group shot at Sossusvlei, from Alex' camera. Jani, me, Alex, Clay, Jason and Karl.

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