ALBERT

Description: The Mars Science Laboratory rover Curiosity has encountered a variety of sedimentary rocks in Gale crater with different grain sizes, diagenetic features, sedimentary structures, and varying degrees of resistance to erosion. Curiosity has drilled three rocks to date and has analyzed the mineralogy, chemical composition, and textures of the samples with the science payload. The drilled rocks are the Sheepbed mudstone at Yellowknife Bay on the plains of Gale crater (John Klein and Cumberland targets), the Dillinger sandstone at the Kimberley on the plains of Gale crater (Windjana target), and a sedimentary unit in the Pahrump Hills in the lowermost rocks at the base of Mt. Sharp (Confidence Hills target). CheMin is the Xray diffractometer on Curiosity, and its data are used to identify and determine the abundance of mineral phases. Secondary phases can tell us about aqueous alteration processes and, thus, can help to elucidate past aqueous environments. Here, we present the secondary mineralogy of the rocks drilled to date as seen by CheMin and discuss past aqueous environments in Gale crater, the potential cementing agents in each rock, and how amorphous materials may play a role in cementing the sediments.

Description: The Pahrump Hills region of Gale crater is a approximately 12 millimeter thick section of sedimentary rocks in the Murray formation, interpreted as the basal geological unit of Mount Sharp. The Mars Science Laboratory, Curiosity, arrived at the Pahrump Hills in September, 2014, and performed a detailed six-month investigation of the sedimentary structures, geochemistry, and mineralogy of the area. During the campaign, Curiosity drilled and delivered three rock samples to its internal instruments, including the CheMin XRD/XRF. The three targets, Confidence Hills, Mojave 2, and Telegraph Peak, contain variable amounts of plagioclase, pyroxene, iron oxides, jarosite, phyllosilicates, and X-ray amorphous material. Hematite was predicted at the base of Mount Sharp from orbital visible/near-IR spectroscopy, and CheMin confirmed this detection. The presence of jarosite throughout Pahrump Hills suggests the sediments experienced acid-sulfate alteration, either in-situ or within the source region of the sediments. This acidic leaching environment is in stark contrast to the environment preserved within the Sheepbed mudstone on the plains of Gale crater. The minerals within Sheepbed, including Fe-saponite, indicate these sediments were deposited in a shallow lake with circumneutral pH that may have been habitable.

Description: The search for predictions of species diversity across environmental gradients has challenged ecologists for decades. The humped-back model (HBM) suggests that plant diversity peaks at intermediate productivity; at low productivity few species can tolerate the environmental stresses, and at high productivity a few highly competitive species dominate. Over time the HBM has become increasingly controversial, and recent studies claim to have refuted it. Here, by using data from coordinated surveys conducted throughout grasslands worldwide and comprising a wide range of site productivities, we provide evidence in support of the HBM pattern at both global and regional extents. The relationships described here provide a foundation for further research into the local, landscape, and historical factors that maintain biodiversity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Fraser, Lauchlan H -- Pither, Jason -- Jentsch, Anke -- Sternberg, Marcelo -- Zobel, Martin -- Askarizadeh, Diana -- Bartha, Sandor -- Beierkuhnlein, Carl -- Bennett, Jonathan A -- Bittel, Alex -- Boldgiv, Bazartseren -- Boldrini, Ilsi I -- Bork, Edward -- Brown, Leslie -- Cabido, Marcelo -- Cahill, James -- Carlyle, Cameron N -- Campetella, Giandiego -- Chelli, Stefano -- Cohen, Ofer -- Csergo, Anna-Maria -- Diaz, Sandra -- Enrico, Lucas -- Ensing, David -- Fidelis, Alessandra -- Fridley, Jason D -- Foster, Bryan -- Garris, Heath -- Goheen, Jacob R -- Henry, Hugh A L -- Hohn, Maria -- Jouri, Mohammad Hassan -- Klironomos, John -- Koorem, Kadri -- Lawrence-Lodge, Rachael -- Long, Ruijun -- Manning, Pete -- Mitchell, Randall -- Moora, Mari -- Muller, Sandra C -- Nabinger, Carlos -- Naseri, Kamal -- Overbeck, Gerhard E -- Palmer, Todd M -- Parsons, Sheena -- Pesek, Mari -- Pillar, Valerio D -- Pringle, Robert M -- Roccaforte, Kathy -- Schmidt, Amanda -- Shang, Zhanhuan -- Stahlmann, Reinhold -- Stotz, Gisela C -- Sugiyama, Shu-ichi -- Szentes, Szilard -- Thompson, Don -- Tungalag, Radnaakhand -- Undrakhbold, Sainbileg -- van Rooyen, Margaretha -- Wellstein, Camilla -- Wilson, J Bastow -- Zupo, Talita -- New York, N.Y. -- Science. 2015 Jul 17;349(6245):302-5. doi: 10.1126/science.aab3916.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Natural Resource Sciences, Thompson Rivers University, Kamloops, BC, Canada. lfraser@tru.ca. ; Department of Biology, University of British Columbia, Okanagan campus, Kelowna, BC, Canada. ; Department of Disturbance Ecology, BayCEER, Uni- versity of Bayreuth, Bayreuth, Germany. ; Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel-Aviv, Israel. ; Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia. ; Faculty of Natural Resources College of Agriculture and Natural Resources, University of Tehran, Iran. ; MTA Centre for Ecological Research, Institute of Ecology and Botany, Vacratot, Hungary, and School of Plant Biology, University of Western Australia, Crawley, Australia. ; Department of Biogeography, BayCEER, University of Bayreuth, Bayreuth, Germany. ; Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada. ; Department of Ecology and Evolutionary Biology, University of Kansas, Manhattan, KS 66047, USA. ; Department of Biology, National University of Mongolia, Ulaanbaatar, Mongolia. ; Department of Botany, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. ; Department of Agricultural, Food and Nutritional Sciences, University of Alberta, Edmonton, AB, Canada. ; Applied Behavioural Ecology and Ecosystem Research Unit, University of South Africa, Johannesberg, South Africa. ; Instituto Multidisciplinario de Biologia Vegetal (IMBIV-CONICET) and Facultad de Ciencias Exactas, Fisicas y Naturales, Universidad Nacional de Cordoba, Cordoba, Espana. ; School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy. ; School of Natural Sciences, Trinity College Dublin, Dublin, Ireland. ; Departamento de Botanica, UNESP - Univ. Estadual Paulista, Rio Claro, Brazil. ; Department of Biology, Syracuse University, Syracuse, NY 13210, USA. ; Department of Biology, University of Akron, Akron, OH 44325, USA. ; Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA. ; Department of Biology, University of Western Ontario, London, ON, Canada. ; Department of Botany, Corvinus University of Budapest, Budapest, Hungary. ; Department of Natural Resources, Islamic Azad University, Nour Branch, Iran. ; Department of Botany, University of Otago, Dunedin, New Zealand. ; International Centre for Tibetan Plateau Ecosystem Management, Lanzhou University, Lanzhou, China. ; Institute of Plant Sciences, University of Bern, Altenbergrain 21, CH-3013, Bern, Switzerland. ; Department of Ecology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. ; Faculty of Agronomy, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. ; Department of Range and Watershed Management, Ferdowsi University of Mashhad, Iran. ; Department of Biology, University of Florida, Gainesville, FL 32611, USA. ; Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA. ; Department of Natural Resource Sciences, Thompson Rivers University, Kamloops, BC, Canada. ; Laboratory of Plant Ecology, Hirosaki University, Hirosaki, Japan. ; Institute of Plant Production, Szent Istvan University, Godollo, Hungary. ; Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, AB, Canada. ; Department of Plant Science, University of Pretoria, Pretoria, South Africa. ; Faculty of Science and Technology, Free University of Bozen-Bolzano, Bolzano, Italy. ; Department of Botany, University of Otago, Dunedin, New Zealand. Landcare Research, Dunedin, New Zealand.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26185249" target="_blank"〉PubMed〈/a〉

Description: Comparing data from the Alpha- Particle X-Ray Spectrometer (APXS) and the Sample Analysis at Mars (SAM) instruments on MSL reveals a strong linear correlation between chlorine and oxygen, further demonstrating the presence of oxychlorine species in Gale Crater and, very likely, globally on Mars. Perchlorate was first discovered on Mars by the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) instrument on the Phoenix lander in 2008. Current hypotheses suggest that the formation of oxychlorine species such as perchlorate or chlorate is a global process and that these species should be globally distributed on Mars [e.g. 2-4]. To date, the SAM and Chemistry and Mineralogy (CheMin) instruments on MSL have analyzed one scooped sample of aeolian material (Rocknest [RN]), and four drilled samples (John Klein [JK], Cumberland [CB], Windjana [WJ], and Confidence Hills [CH]). The APXS instrument has also investigated the same or very similar samples. Although not definitively identified, oxychlorine species have been proposed to explain releases of O2, HCl, and chlorinated hydrocarbon species detected by evolved gas analysis (EGA) with the SAM instrument. We report a strong linear correlation between wt. % Cl detected by APXS and moles O2 detected by SAM during pyrolysis, indicating the presence of oxychlorine species in Gale Crater.

Description: The Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments on the Mars Science Laboratory (MSL) analysed several subsamples of 〈150 m fines from five sites at Gale Crater. Three were in Yellowknife Bay: the Rocknest aeolian bedform ("RN") and drilled Sheepbed mudstone from sites John Klein ("JK") and Cumberland ("CB"). One was drilled from the Windjana ("WJ") site on a sandstone of the Kimberly formation investigated on route to Mount Sharp. Another was drilled from the Confidence Hills ("CH") site on a sandstone of the Murray Formation at the base of Mt. Sharp (Pahrump Hills). Outcrops are sedimentary rocks that are largely of fluvial or lacustrine origin, with minor aeolian deposits.. SAM's evolved gas analysis (EGA) mass spectrometry detected H2O, CO2, O2, H2, SO2, H2S, HCl, NO, and other trace gases, including organic fragments. The identity and evolution temperature (T) of evolved gases can support CheMin mineral detection and place constraints on trace volatile-bearing phases or phases difficult to characterize with XRD (e.g., X-ray amorphous phases). They can also give constraints on sample organic chemistry. Here, we discuss trends in major evolved volatiles from SAM EGA analyses to date.

Description: The National Aeronautics and Space Administration (NASA) has initiated a new Planetary Defense research activity, led by the NASA Ames Research Center. The objective of the effort is to provide tools for reliably assessing the impact damage that Potentially Hazardous Asteroids (PHAs) could inflict on the Earth. This research will support decisions regarding appropriate mitigation action in the event that an impact threat is discovered. The activity includes four interrelated tasks: PHA characterization, physics-based simulations of atmospheric entry breakup, simulations of surface damage due to airbursts, land impacts, or tsunamis, and an integrated assessment of the overall risks posed by potential PHA strikes. This paper outlines the objectives, research approaches, products, and interrelations of the activity's four tasks, and presents an overview of their current progress and preliminary results. Companion papers in this conference provide additional details of the work in the four task areas.

Description: The National Aeronautics and Space Administration (NASA) has initiated a new Planetary Defense research activity, led by the NASA Ames Research Center. The objective of the effort is to provide tools for reliably assessing the impact damage that Potentially Hazardous Asteroids (PHAs) could inflict on the Earth. This research will support decisions regarding appropriate mitigation action in the event that an impact threat is discovered. The activity includes four interrelated tasks: PHA characterization, physics-based simulations of atmospheric entry/breakup, simulations of surface damage due to airbursts, land impacts, or tsunamis, and an integrated assessment of the overall risks posed by potential PHA strikes. This paper outlines the objectives, research approaches, products, and interrelations of the activitys four tasks, and presents an overview of their current progress and preliminary results. Companion papers in this conference provide additional details of the work in the four task areas.

Description: No abstract available

Description: Atmospheric carbon dioxide records indicate that the land surface has acted as a strong global carbon sink over recent decades, with a substantial fraction of this sink probably located in the tropics, particularly in the Amazon. Nevertheless, it is unclear how the terrestrial carbon sink will evolve as climate and atmospheric composition continue to change. Here we analyse the historical evolution of the biomass dynamics of the Amazon rainforest over three decades using a distributed network of 321 plots. While this analysis confirms that Amazon forests have acted as a long-term net biomass sink, we find a long-term decreasing trend of carbon accumulation. Rates of net increase in above-ground biomass declined by one-third during the past decade compared to the 1990s. This is a consequence of growth rate increases levelling off recently, while biomass mortality persistently increased throughout, leading to a shortening of carbon residence times. Potential drivers for the mortality increase include greater climate variability, and feedbacks of faster growth on mortality, resulting in shortened tree longevity. The observed decline of the Amazon sink diverges markedly from the recent increase in terrestrial carbon uptake at the global scale, and is contrary to expectations based on models.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Brienen, R J W -- Phillips, O L -- Feldpausch, T R -- Gloor, E -- Baker, T R -- Lloyd, J -- Lopez-Gonzalez, G -- Monteagudo-Mendoza, A -- Malhi, Y -- Lewis, S L -- Vasquez Martinez, R -- Alexiades, M -- Alvarez Davila, E -- Alvarez-Loayza, P -- Andrade, A -- Aragao, L E O C -- Araujo-Murakami, A -- Arets, E J M M -- Arroyo, L -- Aymard C, G A -- Banki, O S -- Baraloto, C -- Barroso, J -- Bonal, D -- Boot, R G A -- Camargo, J L C -- Castilho, C V -- Chama, V -- Chao, K J -- Chave, J -- Comiskey, J A -- Cornejo Valverde, F -- da Costa, L -- de Oliveira, E A -- Di Fiore, A -- Erwin, T L -- Fauset, S -- Forsthofer, M -- Galbraith, D R -- Grahame, E S -- Groot, N -- Herault, B -- Higuchi, N -- Honorio Coronado, E N -- Keeling, H -- Killeen, T J -- Laurance, W F -- Laurance, S -- Licona, J -- Magnussen, W E -- Marimon, B S -- Marimon-Junior, B H -- Mendoza, C -- Neill, D A -- Nogueira, E M -- Nunez, P -- Pallqui Camacho, N C -- Parada, A -- Pardo-Molina, G -- Peacock, J -- Pena-Claros, M -- Pickavance, G C -- Pitman, N C A -- Poorter, L -- Prieto, A -- Quesada, C A -- Ramirez, F -- Ramirez-Angulo, H -- Restrepo, Z -- Roopsind, A -- Rudas, A -- Salomao, R P -- Schwarz, M -- Silva, N -- Silva-Espejo, J E -- Silveira, M -- Stropp, J -- Talbot, J -- ter Steege, H -- Teran-Aguilar, J -- Terborgh, J -- Thomas-Caesar, R -- Toledo, M -- Torello-Raventos, M -- Umetsu, R K -- van der Heijden, G M F -- van der Hout, P -- Guimaraes Vieira, I C -- Vieira, S A -- Vilanova, E -- Vos, V A -- Zagt, R J -- England -- Nature. 2015 Mar 19;519(7543):344-8. doi: 10.1038/nature14283.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉School of Geography, University of Leeds, Leeds LS2 9JT, UK. ; 1] School of Geography, University of Leeds, Leeds LS2 9JT, UK. [2] Geography, College of Life and Environmental Sciences, University of Exeter, Rennes Drive, Exeter EX4 4RJ, UK. ; 1] Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, Berkshire SL5 7PY, UK. [2] School of Marine and Tropical Biology, James Cook University, Cairns, 4870 Queenland, Australia. ; Jardin Botanico de Missouri, Prolongacion Bolognesi Mz.e, Lote 6, Oxapampa, Pasco, Peru. ; Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford OX1 3QK, UK. ; 1] School of Geography, University of Leeds, Leeds LS2 9JT, UK. [2] Department of Geography, University College London, Pearson Building, Gower Street, London WC1E 6BT, UK. ; School of Anthropology and Conservation, Marlowe Building, University of Kent, Canterbury CT1 3EH, UK. ; Servicios Ecosistemicos y Cambio Climatico, Jardin Botanico de Medellin, Calle 73 no. 51 D-14, C.P. 050010, Medellin, Colombia. ; Center for Tropical Conservation, Duke University, Box 90381, Durham, North Carolina 27708, USA. ; Biological Dynamics of Forest Fragment Project (INPA &STRI), C.P. 478, Manaus AM 69011-970, Brazil. ; 1] Geography, College of Life and Environmental Sciences, University of Exeter, Rennes Drive, Exeter EX4 4RJ, UK. [2] National Institute for Space Research (INPE), Av. Dos Astronautas, 1758, Sao Jose dos Campos, Sao Paulo 12227-010, Brazil. ; Museo de Historia Natural Noel Kempff Mercado, Universidad Autonoma Gabriel Rene Moreno, Casilla 2489, Av. Irala 565, Santa Cruz, Bolivia. ; Alterra, Wageningen University and Research Centre, PO Box 47, 6700 AA Wageningen, The Netherlands. ; UNELLEZ-Guanare, Programa de Ciencias del Agro y el Mar, Herbario Universitario (PORT), Mesa de Cavacas, Estado Portuguesa, 3350 Venezuela. ; Biodiversiteit en Ecosysteem Dynamica, University of Amsterdam, Postbus 94248, 1090 GE Amsterdam, The Netherlands. ; 1] Institut National de la Recherche Agronomique, UMR EcoFoG, Campus Agronomique, 97310 Kourou, French Guiana. [2] International Center for Tropical Botany, Department of Biological Sciences, Florida International University, Miami, Florida 33199, USA. ; Universidade Federal do Acre, Campus de Cruzeiro do Sul, Rio Branco, Brazil. ; INRA, UMR 1137 ''Ecologie et Ecophysiologie Forestiere'' 54280 Champenoux, France. ; Embrapa Roraima, Caixa Postal 133, Boa Vista, RR, CEP 69301-970, Brazil. ; Universidad Nacional San Antonio Abad del Cusco, Av. de la Cultura N degrees 733, Cusco, Peru. ; 1] School of Geography, University of Leeds, Leeds LS2 9JT, UK. [2] International Master Program of Agriculture, College of Agriculture and Natural Resources, National Chung Hsing University, Taichung 40227, Taiwan. ; Universite Paul Sabatier CNRS, UMR 5174 Evolution et Diversite Biologique, Batiment 4R1, 31062 Toulouse, France. ; Northeast Region Inventory and Monitoring Program, National Park Service, 120 Chatham Lane, Fredericksburg, Virginia 22405, USA. ; Andes to Amazon Biodiversity Program, Puerto Maldonado, Madre de Dios, Peru. ; Universidade Federal do Para, Centro de Geociencias, Belem, CEP 66017-970 Para, Brazil. ; Universidade do Estado de Mato Grosso, Campus de Nova Xavantina, Caixa Postal 08, CEP 78.690-000, Nova Xavantina MT, Brazil. ; Department of Anthropology, University of Texas at Austin, SAC Room 5.150, 2201 Speedway Stop C3200, Austin, Texas 78712, USA. ; Department of Entomology, Smithsonian Institution, PO Box 37012, MRC 187, Washington DC 20013-7012, USA. ; Cirad, UMR Ecologie des Forets de Guyane, Campus Agronomique, 97310 Kourou, French Guiana. ; 1] School of Geography, University of Leeds, Leeds LS2 9JT, UK. [2] Instituto de Investigaciones de la Amazonia Peruana, Av. A. Jose Quinones km 2.5, Iquitos, Peru. ; World Wildlife Fund, 1250 24th Street NW, Washington DC 20037, USA. ; Centre for Tropical Environmental and Sustainability Science (TESS) and School of Marine and Environmental Sciences, James Cook University, Cairns, Queensland 4878, Australia. ; Instituto Boliviano de Investigacion Forestal, C.P. 6201, Santa Cruz de la Sierra, Bolivia. ; National Institute for Research in Amazonia (INPA), C.P. 478, Manaus, Amazonas, CEP 69011-970, Brazil. ; 1] FOMABO, Manejo Forestal en las Tierras Tropicales de Bolivia, Sacta, Bolivia. [2] Escuela de Ciencias Forestales (ESFOR), Universidad Mayor de San Simon (UMSS), Sacta, Bolivia. ; Universidad Estatal Amazonica, Facultad de Ingenieria Ambiental, Paso lateral km 2 1/2 via Napo, Puyo, Pastaza, Ecuador. ; National Institute for Research in Amazonia (INPA), C.P. 2223, 69080-971, Manaus, Amazonas, Brazil. ; Universidad Autonoma del Beni, Campus Universitario, Av. Ejercito Nacional, Riberalta, Beni, Bolivia. ; 1] Instituto Boliviano de Investigacion Forestal, C.P. 6201, Santa Cruz de la Sierra, Bolivia. [2] Forest Ecology and Forest Management Group, Wageningen University, PO Box 47, 6700 AA Wageningen, The Netherlands. ; 1] Center for Tropical Conservation, Duke University, Box 90381, Durham, North Carolina 27708, USA. [2] The Field Museum, 1400 South Lake Shore Drive, Chicago, Illinois 60605-2496, USA. ; Forest Ecology and Forest Management Group, Wageningen University, PO Box 47, 6700 AA Wageningen, The Netherlands. ; Universidad Nacional de la Amazonia Peruana, Iquitos, Loreto, Peru. ; Instituto de Investigaciones para el Desarrollo Forestal (INDEFOR), Universidad de Los Andes, Facultad de Ciencias Forestales y Ambientales, Conjunto Forestal, C.P. 5101, Merida, Venezuela. ; Iwokrama International Centre for Rainforest Conservation and Development, 77 High Street Kingston, Georgetown, Guyana. ; Museu Paraense Emilio Goeldi, Av. Magalhaes Barata, 376 - Sao Braz, CEP 66040-170, Belem PA, Brazil. ; UFRA, Av. Presidente Tancredo Neves 2501, CEP 66.077-901, Belem, Para, Brazil. ; Museu Universitario, Universidade Federal do Acre, Rio Branco AC 69910-900, Brazil. ; European Commission - DG Joint Research Centre, Institute for Environment and Sustainability, Via Enrico Fermi 274, 21010 Ispra, Italy. ; 1] Naturalis Biodiversity Center, PO Box, 2300 RA, Leiden, The Netherlands. [2] Ecology and Biodiversity Group, Utrecht University, PO Box 80084, 3508 TB Utrecht, The Netherlands. ; Museo de Historia Natural Alcide D'Orbigny, Av. Potosi no 1458, Cochabamba, Bolivia. ; 1] School of Earth and Environmental Science, James Cook University, Cairns, Queensland 4870, Australia. [2] Centre for Tropical Environmental and Sustainability Science (TESS) and School of Marine and Tropical Biology, James Cook University, Cairns, Queensland 4878, Australia. ; 1] Northumbria University, School of Geography, Ellison Place, Newcastle upon Tyne, Newcastle NE1 8ST, UK. [2] University of Wisconsin, Milwaukee, Wisconsin 53202, USA. [3] Smithsonian Tropical Research Institute, Apartado Postal 0843-03092, Panama, Republic of Panama. ; Van der Hout Forestry Consulting, Jan Trooststraat 6, 3078 HP Rotterdam, The Netherlands. ; Universidade Estadual de Campinas, NEPAM, Rua dos Flamboyants, 155- Cidade Universitaria Zeferino Vaz, Campinas, CEP 13083-867, Sao Paulo, Brazil. ; 1] Universidad Autonoma del Beni, Campus Universitario, Av. Ejercito Nacional, Riberalta, Beni, Bolivia. [2] Centro de Investigacion y Promocion del Campesinado, regional Norte Amazonico, C/ Nicanor Gonzalo Salvatierra N degrees 362, Casilla 16, Riberalta, Bolivia. ; Tropenbos International, PO Box 232, 6700 AE Wageningen, The Netherlands.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25788097" target="_blank"〉PubMed〈/a〉

Description: The Sample Analysis at Mars (SAM) instrument detected at least 4 distinct CO2 release during the pyrolysis of a sample scooped from the Rocknest (RN) eolian deposit. The highest peak CO2 release temperature (478-502 C) has been attributed to either a Fe-rich carbonate or nano-phase Mg-carbonate. The objective of this experimental study was to evaluate the thermal evolved gas analysis (T/EGA) characteristics of a series of terrestrial Fe-rich carbonates under analog SAM operating conditions to compare with the RN CO2 releases. Natural Fe-rich carbonates (〈53 microns) with varying Fe amounts (Fe(0.66)X(0.34)- to Fe(0.99)X(0.01)-CO3, where X refers to Mg and/or Mn) were selected for T/EGA. The carbonates were heated from 25 to 715 C (35 C/min) and evolved CO2 was measured as a function of temperature. The highest Fe containing carbonates (e.g., Fe(0.99)X(0.01)-CO3) yielded CO2 peak temperatures between 466-487 C, which is consistent with the high temperature RN CO2 release. The lower Fe-bearing carbonates (e.g., Fe(0.66)X(0.34)CO3) did not have peak CO2 release temperatures that matched the RN peak CO2 temperatures; however, their entire CO2 releases did occur within RN temperature range of the high temperature CO2 release. Results from this laboratory analog analysis demonstrate that the high temperature RN CO2 release is consistent with Fe-rich carbonate (approx.0.7 to 1 wt.% FeCO3). The similar RN geochemistry with other materials in Gale Crater and elsewhere on Mars (e.g., Gusev Crater, Meridiani) suggests that up to 1 wt. % Fe-rich carbonate may occur throughout the Gale Crater region and could be widespread on Mars. The Rocknest Fe-carbonate may have formed from the interaction of reduced Fe phases (e.g., Fe2+ bearing olivine) with atmospheric CO2 and transient water. Alternatively, the Rocknest Fe-carbonate could be derived by eolian processes that have eroded distally exposed deep crustal material that possesses Fe-carbonate that may have formed through metamorphic and/or metasomatic processes.