Large sulfur isotope fractionations in Martian sediments at Gale crater

Variability in the sulfur isotopic composition in sediments can reflect atmospheric, geologic and biological processes. Evidence for ancient fluvio-lacustrine environments at Gale crater on Mars and a lack of efficient crustal recycling mechanisms on the planet suggests a surface environment that was once warm enough to allow the presence of liquid water, at least for discrete periods of time, and implies a greenhouse effect that may have been influenced by sulfur-bearing volcanic gases. Here we report in situ analyses of the sulfur isotopic compositions of SO2 volatilized from ten sediment samples acquired by NASA’s Curiosity rover along a 13 km traverse of Gale crater. We find large variations in sulfur isotopic composition that exceed those measured for Martian meteorites and show both depletion and enrichment in 34S. Measured values of δ34S range from −47 ± 14‰ to 28 ± 7‰, similar to the range typical of terrestrial environments. Although limited geochronological constraints on the stratigraphy traversed by Curiosity are available, we propose that the observed sulfur isotopic signatures at Gale crater can be explained by equilibrium fractionation between sulfate and sulfide in an impact-driven hydrothermal system and atmospheric processing of sulfur-bearing gases during transient warm periods

Community land formalization and company land acquisition procedures: A review of 33 procedures in 15 countries

Indigenous and community lands, crucial for rural livelihoods, are typically held under informal customary tenure arrangements. This can leave the land vulnerable to outside commercial interests, so communities may seek to formalize their land rights in a government registry and obtain an official land document. But this process can be time-consuming and complex, and in contrast, companies can acquire land relatively quickly and find shortcuts around regulatory burdens. This article reviews and maps 19 community land formalization and 14 company land acquisition procedures is 15 countries in Africa, Asia and Latin America. Comparing community and company procedures identifies multiple sources of inequity

Seeing people through the trees : scaling up efforts to advance rights and address poverty, conflict and climate change

Forest areas have an integral role in the development agenda of the next several decades because of the myriad challenges that converge within their landscapes. Donor agencies and policy-makers can change historical patterns of forest governance and management as a first and critical step toward addressing the impending global challenges of climate change, ongoing conflict and persistent poverty. The report references past models of forest management to demonstrate the weaknesses in prior governance structures while emphasizing gaps and opportunities for the strategic involvement of the international community. The key messages and recommendations to emerge from this literature speak to the global development community, country governments and civil society regarding their roles in forest tenure reform and improved governance

Characterization of alteration phases on Potash-Lime-Silica glass

Glass with Potash–Lime–Silica (PLS) composition was typically produced for the cathedral windows during the Middle Age in Central and Northern Europe and is known to be very sensitive to the attack of the atmospheric pollutants. PLS glass, containing different amounts of K2O (sample V1 = 15 wt%, V2 = 20 wt%, V3 = 25 wt%), was produced and aged in concentrated boiling H2SO4 and in high temperature-high pressure water, to simulate separately the two alteration processes of leaching (ion exchange) and dissolution, respectively. The aged samples were studied by micro-Raman spectroscopy, by XRPD and by SEM–EDS technique to identify the neo-formed crystalline phases, to get deeper insight into degradation and stability of these systems. The behavior of the glasses as revealed by Raman spectroscopy depends on the K2O content. Gypsum (CaSO42H2O), bassanite (CaSO41/2H2O) and anhydrite (CaSO4) are found on the alteration layer of the V2 and V3 leached samples. The water aged V1 and V2 glasses show the Raman features of the phyllosilicates gyrolite (Ca16Si24O60(OH)814H2O) and reyerite (KCa14Si24O60(OH)55H2O) together with hydroxyapatite (Ca5(PO4)3OH). In the alteration layer of the V3 glass, the Raman spectra suggest a mixture of the Ca–K silicate charoite (K5Ca8(Si6O15)2Si2O9(OH)3(H2O)) and hydroxyapatite