Abstract-Sayh al Uhaymir (SaU) 094 is a 223.3 g, partially crusted, strongly to very strongly shocked melanocratic olivine-porphyric rock of the shergottite group showing a microgabbroic texture. The rock consists of pyroxene (52.0-58.2 vol%}-dominantly prismatic pigeonite (Enw-6SFs2D-27W07-9) associated with minor augite (En46-49FsI5-l6W02S-31)-brown (shock-oxidized) olivine (F0 6S-69; 22.1-31 %), completely isotropic interstitial plagioclase glass (maske1ynite; AnSO-640rO.3-0.9; 8.6-13.0%), chromite and titanian magnesian chromite (0.9-1.0%), traces of ilmenite (IlmSo-S6)' pyrrhotite (Fen-IOO; 0.1-0.2%), merrillite «<0.1%), and pockets (4.8-6.7%) consisting of green basaltic to basaltic andesitic shock glass that is partially devitrified into a brown to black product along boundaries with the primary minerals. The average maximum dimensions of minerals are: olivine (l.5 mm), pyroxene (0.3 mm) and maskelynite (0.3 mm). Primary melt inclusions in olivine and chromite are common and account for 0.1-0.6% ofthe rock. X-ray tomography revealed that the specimen contains -0.4 vol% of shock-melt associated vesicles, up to 3 mm in size, which show a preferred orientation. Fluidization of the maskelynite, melting and recrystallization of pyroxene, olivine and pyrrhotite indicate shock stage S6. Minor terrestrial weathering resulted in calciteveining and minor oxidation of sulfides. The meteorite is interpreted as paired with SaU 005/008/051. The modal composition is similar to Dar al Gani 476/489/670/735/876, with the exception that neither mesostasis nor titanomagnetite nor apatite are present and that all phases show little zonation. The restricted mineral composition, predominance ofchromite among the oxides, and abundance ofolivine indicate affinities to the lherzolitic shergottites.835
Wetlands in semi-arid Africa are vital as water resource for local inhabitants and for biodiversity, but they are prone to strong seasonal fluctuations. Lac Bam is the largest natural freshwater lake in Burkina Faso, its water is mixed with patches of floating or flooded vegetation, and very turbid and sediment-rich. These characteristics as well as the usual cloud cover during the rainy season can limit the suitability of optical remote sensing data for monitoring purposes. This study demonstrates the applicability of weather-independent dual-polarimetric Synthetic Aperture Radar (SAR) data for the analysis of spatio-temporal wetland dynamics. A TerraSAR-X repeat-pass time series of dual-co-polarized HH-VV StripMap data-with intervals of 11 days, covering two years (2013)(2014)(2015) from the rainy to the dry season-was processed to normalized Kennaugh elements and classified mono-temporally and multi-temporally. Land cover time series and seasonal duration maps were generated for the following four classes: open water, flooded/floating vegetation, irrigated cultivation, and land (non-wetland). The added value of dual-polarimetric SAR data is demonstrated by significantly higher multitemporal classification accuracies, where the overall accuracy (88.5%) exceeds the classification accuracy using single-polarimetric SAR intensity data (82.2%). For relevant change classes involving flooded vegetation and irrigated fields dual-polarimetric data (accuracies: 75%-97%) are favored to single-polarimetric data (42%-87%). This study contributes to a better understanding of the dynamics of semi-arid African wetlands in terms of water areas including water with flooded vegetation, and the location and timing of irrigated cultivations.
We report on the MARS2013 mission, a 4-week Mars analog field test in the northern Sahara. Nineteen experiments were conducted by a field crew in Morocco under simulated martian surface exploration conditions, supervised by a Mission Support Center in Innsbruck, Austria. A Remote Science Support team analyzed field data in near real time, providing planning input for the management of a complex system of field assets; two advanced space suit simulators, four robotic vehicles, an emergency shelter, and a stationary sensor platform in a realistic work flow were coordinated by a Flight Control Team. A dedicated flight planning group, external control centers for rover tele-operations, and a biomedical monitoring team supported the field operations. A 10 min satellite communication delay and other limitations pertinent to human planetary surface activities were introduced. The fields of research for the experiments were geology, human factors, astrobiology, robotics, tele-science, exploration, and operations research. This paper provides an overview of the geological context and environmental conditions of the test site and the mission architecture, in particular the communication infrastructure emulating the signal travel time between Earth and Mars. We report on the operational work flows and the experiments conducted, including a deployable shelter prototype for multiple-day extravehicular activities and contingency situations.
Surface water is a critical resource in semiarid West-African regions that are frequently exposed to droughts. Natural and artificial wetlands are of high importance for different livelihoods, particularly during the dry season, from October/November until May. However, wetlands largely go unmonitored. In this work, remote sensing is used to monitor wetlands in semiarid Burkina Faso over large areal extents along a gradient of different rainfall and land use characteristics. Time series of data from the Moderate Resolution Imaging Spectrometer (MODIS) from 2000 to 2012 is used for near-infrared (NIR)-based water monitoring using a latitudinal threshold gradient approach. The occurrence of 21 new water bodies with a size larger than 0.5 km 2 over the 13-year analysis period results from a postclassification change detection. Yearly cumulative spatiotemporal analysis shows lower water extents in the drought seasons of 2000-2001, 2004-2005, and 2011-2012. Multiple wetlands indicate a positive trend toward a larger yearly maximum area, but a negative trend toward shorter flooding duration. Such a negative trend is observed particularly for natural wetlands. The temporal behavior of five selected case studies demonstrates that monthly negative anomalies of watercovered areas coincide with the occurrence of drought seasons. The successful application of remote sensing time series as a tool to monitor wetlands in semiarid regions is presented, and the potential of novel early warning indicators of drought from remote sensing is demonstrated.
a b s t r a c tDivergent adaptation to climate variability produces unequal adaptive capacities between user groups and contributes to a contested landscape. This article examines divergent adaptations in the context of land tenure shifts in the pastoral zone of Niger. The management of the pastoral commons is shifting from a commonly-shared to private regime as former pastoralists take up new livelihoods, such as irrigated gardening. A method combining political ecology and remote sensing is used to study social ecological system (SES) dynamics in order to demonstrate the relationship between divergent adaptation, water-based conflict, land tenure shifts and land use/land cover change. Examining pastoral and agro-pastoral users' historical perceptions of land use and tenure change, results indicate that disputes over the access to and use of commonly shared natural resources are linked to increasing enclosures of ephemeral and permanent lakes in the pastoral zone of Niger. Remote sensing-derived information is used to identify and quantify the area and volume of enclosures around commonly shared water sources in the northern pastoral zone of Niger from 2003 to 2013. The study identifies the government-supported development of irrigated gardens in the pastoral zone as a divergent adaptation with its related conflict dynamics between user groups and highlights the land tenure shifts from a commonly to a privately managed regime. The findings have broader implications for the wider Sahel and provide recommendations as to how adaptation programs could be better designed and implemented in the pastoral system.
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