A Comparative Analysis of Evaporate Sediments on Earth and Mars：Implications for the Climate Change on Mars

The knowledge of Martian salts has gone through substantial changes during the past decades. In the 70th of last century, Viking landers have noticed the existence of salts on Mars. Several salt species have been suggested from then on, such as sulfates and chlorides. However, their origin was a mystery due to the lack of observations. The recent explorations and related studies at the beginning of this century revealed that the crustal composition of Mars is similar to that of Earth, and it was hypothesized that almost one third of Martian surface was covered by oceans and lakes in the early stage of Mars. The huge water bodies may have dissolved a large quantity of ions from Martian primary rocks during the whole Noachian and Hesperian epoch. After the enormous drought event happened during the late Hesperian and the early Amazonian, these dissolved ions have formed huge salts deposits and most of them were preserved on Mars until today. To date, carbonates, sulfates, chlorides have all been detected by orbital remote sensing and by landers and rovers. However, the salt mineral assemblages on Mars seems to have some differences from those on Earth, e.g., rich in sulfates and lack of massive carbonates. To explain this difference, we propose that most of the surface carbonates precipitated from the ancient oceans may have been dissolved by the later ubiquitous acidic fluids originated from the global volcanism in the Hesperian era, and formed the enormous sulfate deposits as detected, and this hypothesis seems to be supported by the evidence that most of the sulfate deposits distribute around the Tharsis volcanic province while the survived carbonates located far from it. This process can release most of the carbon on Mars to the atmosphere in the form of CO2 and then be erased by the late heavy bombardments, which might have profound influence on the climate change happened in the Hesperian age. The positive correlation between the GRS results of the potassium distributions and the distribution of chlorides on Mars, together with the high Br concentration measured from the evaporate sediments at two Mars exploration rover landing sites, indicate that the brines in the regions where the chlorides deposited may have reached the stage for potassium salts deposition, thus we propose for the first time that potassium salts deposits might be prevalent in these regions.     

Catalog of hard X-ray solar flares detected with Mars Odyssey/HEND from the Mars orbit in 2001–2016

The study of nonstationary processes in the Sun is of great interest, and multi-wavelength observations and the registration of magnetic fields have been carried out using both ground-based telescopes and several specialized spacecraft in near-Earth orbits in recent years. However, the acquisition of new, reliable information on their hard X-ray radiation remains necessary, in particular, if the corresponding spacecraft provide additional information, e.g., in regard to flare observations from directions other than the Sun–Earth direction. This paper presents a catalog of powerful solar flares registered by the High Energy Neutron Detector (HEND) designed at the Space Research Institute of the Russian Academy of Sciences. HEND is mounted onboard the 2001Mars Odyssey spacecraft. It operated successfully during the flight to Mars and is currently operating in near-Mars orbit. Apart from neutrons, HEND is sensitive to hard X-ray (up to 300 keV) and gamma-ray radiation (above 300 keV). This radiation is registered by two scintillators: an outer one that is sensitive to photons above 40 keV and an inner one sensitive to photons above 200 keV. The catalog was created using a new procedure for calibration of the data. For the most powerful 60 solar flares in the visible and far sides of the Sun (for a terrestrial observer), time profiles of the flare radiation summed over all channels of the X-ray, and in some cases the gamma-ray, bands are provided, as well as spectra and characteristics of power-law fits. The results of previous studies of the Sun using HEND and the potential for further use of these data are discussed.     

Earth and Mars – Distinct inner solar system products

Composition of terrestrial planets records planetary accretion, core–mantle and crust–mantle differentiation, and surface processes. Here we compare the compositional models of Earth and Mars to reveal their characteristics and formation processes. Earth and Mars are equally enriched in refractory elements (1.9 × CI), although Earth is more volatile-depleted and less oxidized than Mars. Their chemical compositions were established by nebular fractionation, with negligible contributions from post-accretionary losses of moderately volatile elements. The degree of planetary volatile element depletion might correlate with the abundances of chondrules in the accreted materials, planetary size, and their accretion timescale, which provides insights into composition and origin of Mercury, Venus, the Moon-forming giant impactor, and the proto-Earth. During its formation before and after the nebular disk's lifetime, the Earth likely accreted more chondrules and less matrix-like materials than Mars and chondritic asteroids, establishing its marked volatile depletion. A giant impact of an oxidized, differentiated Mars-like (i.e., composition and mass) body into a volatile-depleted, reduced proto-Earth produced a Moon-forming debris ring with mostly a proto-Earth's mantle composition. Chalcophile and some siderophile elements in the silicate Earth added by the Mars-like impactor were extracted into the core by a sulfide melt (∼0.5% of the mass of the Earth's mantle). In contrast, the composition of Mars indicates its rapid accretion of lesser amounts of chondrules under nearly uniform oxidizing conditions. Mars’ rapid cooling and early loss of its dynamo likely led to the absence of plate tectonics and surface water, and the present-day low surface heat flux. These similarities and differences between the Earth and Mars made the former habitable and the other inhospitable to uninhabitable.     

Development for a postneoliberal era? Sumak kawsay,living well and the limits to decolonisation in Ecuador

Latin American development is being rapidly transformed, with popularly elected governments embarking on reversals of neoliberalism informed by autochthonous notions of human wellbeing. Through a detailed examination of the origins and application of one development model, this article examines the constraints on and limits to postneoliberal development in terms of state-civil society relations and as a form of postcolonial governmentality. Interpreting Ecuadorian sumak kawsay (living well in English) in relation to embedded political cultures, specific opportunity structures, and the dynamic between contentious and electoral politics highlights the extent of room for manoeuvre in rethinking development. As a form of governmentality and pastoral power, Ecuadorian ‘postneoliberalism’ incorporates a constitutional commitment to social rights, collective citizens and the rights of nature. The paper also reveals the difficulty of making a definitive break from neoliberalism, which remains pervasive in practice, conceptualisations and state formations. Moreover, although various forms of anti-colonial ‘border thinking’ were proposed by social movement’s contentious politics, the paper argues that sumak kawsay works to sustain postcolonial conditions of development.     

A tale of two institutions: Shaping O?wi?cim-Auschwitz

For the last sixty years, two institutions have shaped the destiny of the town of O?wi?cim in southern Poland. One of these institutions is globally recognised, its history and development widely researched; the other is well known only amongst Polish industrialists, perhaps Polish economic geographers, and amongst the people of O?wi?cim. These two institutions are the Auschwitz State Museum and the chemical firm Dwory SA. Both institutions have their roots in the German Occupation of Poland 1939-1945. This paper presents the tale of these two institutions in order not only to highlight the need to embed memorial sites in their wider contexts, but also to indicate the impact of such sites as political-economic institutions, with the influence to shape social and economic landscapes. In laying out the geographies of the town and its two major institutions, we draw attention to the ways in which Holocaust memorialisation and post-socialist transformation are articulated with each other, not only here in O?wi?cim, and also with wider processes of social, economic, political and cultural change.     

A virtual capital for the European Union?

This article explores the websites of the key institutions of the European Union to consider whether these applications of the new information and communication technologies may become a functional equivalent of the national capital city in the emerging supranational political arena. Three functions of capital cities are evaluated: that of command centre, showcase and cultural arena. The websites under consideration do provide a representation of the EU command centre, and they also offer detailed information useful for those monitoring and partaking in the EU decision-making process. They are underused as supranational showcase, with the noticeable exception of their institutionalisation of multilingualism. And they do offer a rudimentary EU-wide public space. The findings suggest that there is a real potential that could be exploited by the EU institutions to foster the expression of the supranational community.     

“This is the mess that we are living in”: residents everyday life experiences of living in a stigmatized community

This paper is part of a larger community health study aimed at delineating the determinants of health in Sarnia. The paper specifically investigates Sarnia residents’ daily lived experiences, perceptions of and responses to living within the St. Clair River “Area of Concern” (AOC) as designated by the federal government based on the hypothesis that relatively high levels of environmental pollution in the region are negatively influencing human health. Results from in-depth interviews (N = 27) show that residents of Sarnia are conflicted by the elevation of awareness about environmental health threats by being labelled within an AOC. Residents use their emotional and sensual experiences to adopt appropriate coping strategies to live within a contaminated community. In contextualizing their everyday lived realities, residents argued that living in an AOC demands personal acceptance of the conditions in Sarnia and awareness of “bad air days” to cope with pollution exposure. Yet, residents were not willing to abandon Sarnia because of their cultural, social, and economical attachments to the place they call home. These findings suggest the need for local health policies that incorporate local concerns and perceptions of how environmental pollution affects people’s experiences and well-being. There is a necessity to involve community members as central participants in the process of policy making.     

A constant daylength during the precambrian era?

The semidiurnal atmospheric thermal tide would have been resonant with free oscillations of the atmosphere when the day was ∼ 21 h long, c. 600 Ma ago. Very large atmospheric tides would have resulted, with associated surface pressure oscillations in excess of 10 mbar in the tropics. Near resonance the Sun's gravitational torque on the atmospheric tide - accelerating Earth's rotation - would have been comparable in magnitude to the decelerating lunar torque upon the oceanic tides. The balance of the opposing torques may have long maintained a resonant ∼ 21 h day, perhaps for much of the Precambrian. Because the timescale of lunar orbital evolution is not directly affected, a constant daylength would result in fewer days/month. The hypothesis is shown not to conflict with the available (stromatolitic) evidence. Escape from the resonance could have followed a relatively abrupt global warming, such as that occurring at the end of the Precambrian. Alternatively, escape may simply have followed a major increase in the rate of oceanic tidal dissipation, brought about by the changing topography of the world's oceans. We integrate the history of the lunar orbit with and without a sustained resonance, finding that the impact of a sustained resonance on the other orbital parameters of the Earth-Moon system would not have been large.     

What is social sustainability? A clarification of concepts

Though the concept of sustainable development originally included a clear social mandate, for two decades this human dimension has been neglected amidst abbreviated references to sustainability that have focused on bio-physical environmental issues, or been subsumed within a discourse that conflated ‘development’ and ‘economic growth’. The widespread failure of this approach to generate meaningful change has led to renewed interest in the concept of ‘social sustainability’ and aspects thereof. A review of the literature suggests, however, that it is a concept in chaos, and we argue that this severely compromises its importance and utility. The purpose of this paper is to examine this diverse literature so as to clarify what might be meant by the term social sustainability and highlight different ways in which it contributes to sustainable development more generally. We present a threefold schema comprising: (a) ‘development sustainability’ addressing basic needs, the creation of social capital, justice and so on; (b) ‘bridge sustainability’ concerning changes in behaviour so as to achieve bio-physical environmental goals and; (c) ‘maintenance sustainability’ referring to the preservation - or what can be sustained - of socio-cultural characteristics in the face of change, and the ways in which people actively embrace or resist those changes. We use this tripartite of social sustainabilities to explore ways in which contradictions and complements between them impede or promote sustainable development, and draw upon housing in urban areas as a means of explicating these ideas.     

The Sunda Shelf—A Submerged Amazon Basin?

A crucial and debatable issue in paleoclimatology is the change of terrestrial vegetation and the role of its carbon storage in glacial cycles. In the modern world, the Amazon Basin hosts the largest tropical rainforest and plays a major role of carbon sink, but during the glacial times another large tropical rainforest must have formed in the then emerged Sunda Shelf, SE Asia, and significantly changed the global carbon cycling. Accordingly, ocean drilling expeditions to the Sunda Shelf are being proposed in order to investigate the sea level changes, evolution of river network, vegetation and carbon storage, as well as biogeography of the tropical region over the last millions of years.     

Application of Continuous Wavelet Transform in?Examining Soil Spatial Variation: A?Review

An adequate understanding of soil spatial variation as a function of space and scale is necessary in ecological modeling, environmental prediction, precision agriculture, soil quality assessment and natural resources management. Soil spatial variation can be partitioned into frequencies (scale) and positions (location) by the wavelet transform. This review focuses mainly on different applications of the continuous wavelet transform (CWT) for the identification of the scale and location dependence of soil attributes. We discussed both wavelet spectra and wavelet coherence in our analysis of soil spatial variation. Global wavelet spectra, being the sum of wavelet spectra over all spatial locations at a scale, can be used to examine the dominant scale of variation. Furthermore, some variations at a particular scale persist over all locations (termed global features), whereas others are present at only a few locations (localized features). Wavelet spectra can be used to identify both localized and global features. The combination of localized and global features provides a complete picture of the scale-location information of different processes in the field and may provide better guidance in designing efficient management practices. Wavelet coherency partitions the total correlation between two variables into correlations at different scales and locations, while also revealing the scale- and location-specific relationship between those two variables. This relationship may be helpful in developing predictive links between one property and another.     

Was Archean Dharwar Craton ever stable? A seismic perspective

Indian shield comprising a number of Archean-Proterozoic cratons, forms one of the most dynamic, sheared and deformed continental segment amongst all stable areas of the earth. However, for a long time it has been believed that its lithosphere remained unaffected by episodic tectono-thermal and volcanic perturbations. Using available seismic data, an attempt has been made to study the seismic structure of the south Indian shield in order to examine the effects of such mantle processes on its overall crust-mantle structure. Our study suggests that by and large, Indian crust is intermediate to mafic in composition. On an average, only a couple of kilometers of the initially formed upper (granitic-gneissic) crust now remains in place and a thick chunk of the original lower crust has been consumed by the underlying thermally buoyant mantle due to sub-crustal erosion and then subsequently replaced by possibly as much as about 16 km thick magma layer on either side of the Moho. This study throws a new light on the geologic and geodynamic evolution of this region and contradicts the hitherto believed paleo-stability of the Indian shield.     

A modi?ed failure criterion for transversely isotropic rocks

A modified failure criterion is proposed to determine the strength of transversely isotropic rocks. Me-chanical properties of some metamorphic and sedimentary rocks including gneiss, slate, marble, schist, shale, sandstone and limestone, which show transversely isotropic behavior, were taken into consider-ation. Afterward, introduced triaxial rock strength criterion was modified for transversely isotropic rocks. Through modification process an index was obtained that can be considered as a strength reduction parameter due to rock strength anisotropy. Comparison of the parameter with previous anisotropy in-dexes in literature showed reasonable results for the studied rock samples. The modified criterion was compared to modified Hoek-Brown and Ramamurthy criteria for different transversely isotropic rocks. It can be concluded that the modified failure criterion proposed in this study can be used for predicting the strength of transversely isotropic rocks.     

The slope aspect: A predisposing factor for landsliding?

The influence of slope aspect on the distribution of landslides was studied in the Milia and Roglio basins in Tuscany, Italy. For each basin, the new Tuscany region landslide inventory that was initiated in 2010 was used. The landslides were split into separate datasets based on their prevailing movement typology. To assess the results that were obtained from the different slope aspect values, maps of the lithology, slope angle, distances to streams, and distances to tectonic lineaments were included in the bivariate statistical analysis as comparison terms. For each basin, all of the geo-environmental factor maps were compared with the different landslide typologies with GIS software. Pearson's Chi² (χ²) coefficient was used to test the degree of spatial association between each predictor variable and landslide type. In addition, Cramer's V test was used to quantify the strength of the degree of association. Next, a conditional analysis was applied to all of the possible combinations that occurred between the slope aspect and other landslide-predisposing factors. Overall, the slope aspect significantly affected the distribution of superficial landslide types, but apparently not that of other landslide types.     

A crystallographic and m?ssbauer spectroscopy study of Fe

The crystal chemistry of garnet solid solutions on the Fe ₃ ²⁺ Al₂Si₃O₁₂-Fe ₃ ²⁺ Fe ₂ ³⁺ Si₃O₁₂ (almandine-“skiagite”) and Ca₃Fe ₂ ³⁺ Si₃O₁₂-Fe ₃ ²⁺ Fe ₂ ³⁺ Si₃O₁₂ (andradite-“skiagite”) joins have been investigated by single-crystal X-ray structure refinements and M?ssbauer spectroscopy. Together, these two solid solution series encompass the complete range in Fe³⁺/ΣFe from 0.0 to 1.0. All garnets are isotropic and were re0fined in the Ia d space group. Small excess volumes of mixing are observed in andradite-“skiagite” solid solutions (W _v =1.0±0.2 cm³ mol^-1) and along the almandine-“skiagite” join (W _v =-0.77±0.17cm³ mol^-1). The octahedral (Al, Fe³⁺)-O bond lengths show a much greater variation across the almandine-skiagite join compared to the andradite-skiagite garnets. The dodecahedral (X)-O bond lengths show the opposite behaviour. In andradite-“skiagite” solid solutions, the octahedral site passes from being flattened to elongated parallel to the 3 axis of symmetry with increasing “skiagite” content. A perfect octahedron occurs in a composition of ≈35 mol% “skiagite”. The occupancy of the neighboring dodecahedral sites has the greatest effect on octahedral distortion and vice versa. The M?ssbauer hyperfine parameters of Fe²⁺remain constant in both solid solutions. The hyperfine parameters of Fe³⁺ (at room temperature: centre shift=0.32–0.40 mm/sec, quadrupole splitting (QS)≈0.21–0.55 mm/ sec) indicate that all Fe³⁺ is in octahedral coordination. The Fe³⁺ parameters are nearly constant in almandine-“skiagite” solid solutions, but vary significantly across the andradite-“skiagite” join. The structural unit that contributes to the electric field gradient of the octahedral site is different from that of the coordinating oxygen polyhedron, probably involving the neighboring dodeca-hedral sites.     

Melting of clinopyroxene + magnesite in iron-bearing planetary mantles and implications for the Earth and Mars

The assemblage clinopyroxene + magnesite was observed in Earth’s high-pressure metamorphic samples, and its stability in subducting slabs was confirmed by experiments. Recent studies also suggested that the fO₂ variations observed in SNC meteorites can be explained by polybaric graphite-CO-CO₂ equilibria in the Martian mantle. Although there is no direct evidence for the stability of the cpx + mc assemblage in Mars mantle, its high-pressure–high-temperature decomposition to cpx + fo + CO₂ makes it a good analogue for the source of carbon metasomatism, in particular, to study nakhlites formation. Iron, which is present in the Earth’s and Martian mantles, may, however, influence the speciation of carbon. We performed experiments on a clinopyroxene + magnesite assemblage at 1.8 and 3.0 GPa and temperatures corresponding to the Earth’s and Martian mantles. The role of iron and of fO₂ was investigated by (1) replacing all or part of the magnesite by siderite FeCO₃, (2) adding Fe⁰ and (3) using graphite C capsules. A carbonate-silicate melt forms at both Earth and Mars conditions. Clinopyroxene and olivine are the main solid phases in the iron-free experiments. Fe²⁺ and Fe⁰ decrease their melting temperatures and increase the silicate fraction in the melt. The produced carbonate-silicate melts may be involved in the formation of some carbon-rich lavas on Earth (e.g., carbonatites, ultramafic lamprophyres, or kamafugites). Our results may also be used to interpret ophiolite samples or inclusions. In particular, we show that wüstite may form in equilibrium with carbonate-silicate melt in opx-(and silica-) poor regions of the mantle below 3 GPa. Our results also confirm the hypothesis of carbon metasomatism in the Martian nakhlites source. Immiscibility or reduction could explain the absence or rarity of C in Martian lavas.     

A fine muddle: (Re) Configuring water conflicts?

In this article, we draw upon ongoing research in periurban Gurugram (formerly Gurgaon) in North–West India on the institutional dynamics around and conflicts over wastewater. Prevailing approaches to analysis of conflicts over natural resources pay scant attention to the role of the nature of the resource per se in shaping the possibilities of conflicts. Further, conflict researchers should pay attention to the difference between conflicts of interest and conflicts. In doing so, they should analyse the role of local norms that may prevent conflicts of interest from erupting into conflicts, while pushing people into situations of forced cooperation.