153 research outputs found

    Detailed Analysis of the Intra-Ejecta Dark Plains of Caloris Basin, Mercury

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    The Caloris basin on Mercury is floored by light-toned plains and surrounded by an annulus of dark-toned material interpreted to be ejecta blocks and smooth, dark, ridged plains. Strangely, preliminary crater counts indicate that these intra-ejecta dark plains are younger than the light-toned plains within the Caloris basin. This would imply a second, younger plains emplacement event, possibly involving lower albedo material volcanics, which resurfaced the original ejecta deposit. On the other hand, the dark plains may be pre-Caloris light plains covered by a thin layer of dark ejecta. Another alternative to the hypothesis of young, dark volcanism is the possibility that previous crater counts have not thoroughly distinguished between superposed craters (fresh) and partly-buried craters (old) and therefore have not accurately determined the ages of the Caloris units. This abstract outlines the tasks associated with a new mapping project of the Caloris basin, intended to improve our knowledge of the geology and geologic history of the basin, and thus facilitate an understanding of the thermal evolution of this region of Mercury

    Characteristics of the Mars Pathfinder Landing Site from CRISM Hyperspectral Imaging

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    Preliminary analysis of CRISM imaging of the Mars Pathfinder landing site is consistent with previously reported results from landed imaging. At tens of meters scale, the surface is largely dust-covered. Lee portions of topographic knobs are reddest and show most evidence for ferric mineralogy. The nearby 1.5-km diameter "Big Crater" exposes olivine, which is atypical of the northern plains. Big Crater may have penetrated northern plains material to expose buried basaltic highlands

    Geology of Libya Montes and the Interbasin Plains of Northern Tyrrhena Terra, Mars: Project Introduction and First Year Work Plan

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    The highland-lowland boundary (HLB) of Mars is interpreted to be a complex tectonic and erosional transition that may hold evidence for past geologic processes and environments. The HLB-abutting margin of the Libya Montes and the interbasin plains of northern Tyrrhena Terra display an exceptional view of the earliest to middle history of Mars that has yet to be fully characterized. This region contains some of the oldest exposed materials on the Martian surface as well as aqueous mineral signatures that may be potential chemical artifacts of early highland formational processes. However, a full understanding of the regions geologic and stratigraphic evolution is remarkably lacking. Some outstanding questions regarding the geologic evolution of Libya Montes and northern Tyrrhena Terra in-clude: Does combining geomorphology and composition advance our understanding of the region s evolution? Can highland materials be subdivided into stratigraphically discrete rock and sediment sequences? What do major physiographic transitions imply about the balanced tectonism, climate change, and erosion? Where is the erosional origin and what is the post-depositional history of channel and plains units? When and in what types of environments did aqueous mineral signatures arise? This abstract introduces the geologic setting, science rationale, and first year work plan of a recently-funded 4-year geologic mapping proposal (project year = calendar year). The objective is to delineate the geologic evolution of Libya Montes and northern Tyrrhena Terra at 1:1M scale using both classical geomorphological and compositional mapping techniques. The funded quadrangles are MTMs 00282, -05282, -10282, 00277, -05277, and -10277

    Challenges in the Search for Perchlorate and Other Hydrated Minerals With 2.1-μm Absorptions on Mars

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    A previously unidentified artifact has been found in Compact Reconnaissance Imaging Spectrometer for Mars targeted I/F data. It exists in a small fraction (<0.05%) of pixels within 90% of images investigated and occurs in regions of high spectral/spatial variance. This artifact mimics real mineral absorptions in width and depth and occurs most often at 1.9 and 2.1 μm, thus interfering in the search for some mineral phases, including alunite, kieserite, serpentine, and perchlorate. A filtering step in the data processing pipeline, between radiance and I/F versions of the data, convolves narrow artifacts (“spikes”) with real atmospheric absorptions in these wavelength regions to create spurious absorption-like features. The majority of previous orbital detections of alunite, kieserite, and serpentine we investigated can be confirmed using radiance and raw data, but few to none of the perchlorate detections reported in published literature remain robust over the 1.0- to 2.65-μm wavelength range

    Initial Results from the MRO Crism Hyperspectral Imaging Spectrometer for the Columbia Hills in Gusev Crater on Mars

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    Initial results from the Mars Reconnaissance Orbiter (MRO) Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument are reported for the Columbia Hills region in Gusev Crater, Mars. The imaged region (data product FRT00003192_07) includes the surface traversed by the Mars Exploration Rover (MER) Spirit. CRISM hyperspectral data (approx. 0.4 to 2.6 micrometers) are compared with multispectral data (approx. 0.4 to 1.0 micrometers) obtained by Spirit's Panoramic Camera (Pancam) instrument

    Scaling sustainability from the organizational periphery to the strategic core : towards a practice-based framework of what practitioners “do”

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    This paper explores what sustainability managers do when attempting to scale sustainability to a strategic level within their organization. Drawing on semistructured interview data with 44 sustainability managers in large, for‐profit companies, we identify three distinct scaling microstrategies that individuals use when scaling sustainability. We label these conforming, leveraging, and shaping. Our analysis also finds that sustainability managers deploy combinations of these microstrategies in three distinct approaches, which we call the assimilation approach, the mobilization approach, and the transition approach. Finally, we interrogate the degree to which employing these different approaches achieves a peripheral, intermediate, or strategic scale of sustainability within the organizations represented in the study. Our paper contributes to theory and practice at the interface of strategy and sustainability by developing a practice‐based Scaling Approach Framework, whereby an assimilation approach is associated with organizations with sustainability at a peripheral scale, a mobilization approach is associated with an intermediate scale of sustainability, and a transition approach is associated with scaling sustainability to a strategic level. From these results, we propose a Scaling Progression Model that reflects the phases that individuals progress through when scaling sustainability.PostprintPeer reviewe

    How social enterprises can contribute to the Sustainable Development Goals (SDGs) – A conceptual framework

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    In the recent 2015 report by Social Enterprise UK - Think Global Trade Social - it is argued that social enterprises have an important role to play in the achievement of the UN’s new Sustainable Development Goals (SDGs). However, with 17 SDGs and no less than 169 associated targets, understanding how social enterprises can contribute to the achievement of these goals remains challenging. Particularly given the diversity of social enterprise models that exist globally. This chapter contributes towards addressing this problem by introducing a framework for conceptualising how social enterprises can contribute to the SDGs, illustrated with global examples. The chapter begins by reviewing what has been written about social enterprises and the SDGs. This is followed by the development and presentation of the conceptual framework. Finally, conclusions and areas for future research on social enterprises and the SDGs are identified
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