DOCSLIB.ORG

Tropical Mountain Glaciers on Mars: Volcano-Ice Interactions and Influences on Glacial Evolution

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Tropical Mountain Glaciers on Mars: Volcano-Ice Interactions and Influences on Glacial Evolution Seventh International Conference on Mars 3123.pdf TROPICAL MOUNTAIN GLACIERS ON MARS: VOLCANO-ICE INTERACTIONS AND INFLUENCES ON GLACIAL EVOLUTION. L. Wilson1 and J. W. Head2; 1Environmental Science Dept., Lancaster University, Lancaster LA1 4YQ, UK ([email protected]); 2Dept. Geological Sciences, Brown University, Providence, RI 02912, USA ([email protected]). Introduction: Late Amazonian fan-shaped the Arsia deposit and are separated by about 25-30 km. deposits on the northwest flanks of the Tharsis Graben, pits and moberg-like ridges characterize the Montes volcanoes are interpreted to have formed as a eastern ridge. The western structure contains a lobe- result of cold-based tropical mountain glaciation [1- shaped plateau and crater near the edge of the hummocky 6] (Figs. 1, 2). Deposits and landforms interpreted to facies, and forms subaerial cones along its northern have formed during subglacial eruptions have been extension, between the inner and outer ridged facies, and documented beneath and within these deposits [4, 7- again outside the glacial deposits to the north. The lobe- 8]. These include low ridges interpreted to be dikes, shaped plateau (~9 km long and 6 km wide) extends lobate deposits interpreted to be steep-sided flows, downslope and the adjacent crater is ~4 km wide and linear mounds and low ridges interpreted to be ~100 m deep. The plateau is ~130-150 m high and moberg-like ridges and cones, and elongated extends from the base of a ridge that is ~350 m high. We depressions and trough-like features interpreted to be interpret the ridge, located along the strike of the linear the result of subglacial and englacial trend, to be a sub-glacial moberg-like ridge, and the phreatomagmatic eruptions. Phreatomagmatic elongate plateau to be a subglacial, sill-like lava flow eruptions could produce enough tephra and country extending from the vent. Superposed on the lobate rock to alter the behavior of the glacier through direct plateau, and extending downslope and out onto the melting, albedo-induced effects, surface insulation, subjacent lava flows, is a sinuous ridge that is generally and influences on the rheology of ice. In some continuous for ~14 km; we interpret this to be an esker places, sufficient meltwater appears to have been draining subglacial eruption-induced meltwater. generated during the intrusion of steep-sided sill-like Adjacent to and downslope from the ridge/lobate plateau subglacial flows to produce subglacial lakes. The the configuration of the drop moraines bows outward for presence of subglacial lakes could have led to local a distance of ~5-10 km. The most prominent drop wet-based conditions, local tongue-like wet based moraine occurs at the distal (downslope) edge of this glacial surges, and to the release of meltwater from inner set of drop moraines and several fluvial channels the margin of the glacier in fluvial drainage channels emerge from its base and extend at least 5-7 km into the or jokulhlaups. In this contribution we examine surrounding terrain. several of these factors from an observational and We interpret this configuration to be the result of modeling point of view. subglacial volcanism and volcanically induced meltwater Arsia Mons Cold-Based Tropical Mountain generation and drainage. Sufficient meltwater appears to Glacier: Subglacial Eruptions, Polythermal have been generated to cause a local transition from Glaciation, and Distal Drainage of Meltwater: At cold-based to wet-based conditions, producing local wet- Arsia Mons, the tropical mountain glacier deposits based surging of a 30-40 km wide portion of the contain features and structures interpreted to otherwise cold-based glacier. In addition, drainage of the represent subglacial and englacial eruptions. Here we meltwater from beneath the glacier out into the describe a series of features that together are surrounding terrain formed local fluvial channels at the interpreted to represent a linear subglacial eruption glacier margin. that caused the production of sufficient meltwater to Subglacial Eruptions and Polythermal Glaciation form eskers, a local wet-based glacial surge that on Mars: The Pavonis Mons Tropical Mountain formed anomalously lobate moraines, and a distal Glacier Steep-Sided Subglacial Flows: Subglacial and series of channels emerging from the edge of the englacial magma in contact with glacial ice can cause glacial deposit and flowing downslope into the melting and produce meltwater. Here we examine the surrounding terrain that is interpreted to represent heating associated with specific features interpreted to be subglacial drainage following the eruption. subglacial eruptions [4,7-8] (Fig. 2) in order to assess A series of NW-trending preglacial lava flows their relative ability to melt glacial ice and to produce extend down the flanks of Arsia and the fan-shaped sufficient meltwater to potentially cause a transition from glacial deposits are superposed. Facies in the NW cold-based to wet-based glacial conditions. We find that part of the Arsia deposit include concentric ridged among the range of subglacial eruption features, steep- deposits interpreted to be drop moraines and sided subglacial lava flows are the most efficient in hummocky deposits interpreted to be sublimation producing meltwater. Due to their sill-like nature and tills. Two generally parallel graben-ridge systems the continuing supply of overlying ice replacing draining trend for several hundred km across the NW part of meltwater, water volumes of up to 450 km3 can be Seventh International Conference on Mars 3123.pdf generated from a typical 100 km long, 15 km wide, sources of sediment include global airborne dust, 500 m thick subglacial flow emplaced at a plausible volcano summit and flank explosive tephra-forming effusion rate of ~10,000 m3/s over a 2.5 year period. eruptions, country rocks from phreatomagmatic This volume of meltwater is equivalent to a layer eruptions, and rocky debris derived from alcoves and averaging 4.5 m deep below an area equivalent to the scarps near the accumulation area. Abundant evidence maximum extent of the Pavonis tropical mountain suggests that the glaciers were cold-based and thus glacier but more importantly is equivalent to an incorporation of subglacial debris into the glacial ice was average water layer thickness of 45 m beneath the minimal. specific zone between the flows and the distal part of Subglacial volcanic eruptions occurring during the the lobe. time of the presence of the glaciers show evidence for This analysis suggests that there may have been dike, sill, subglacial flow, moberg ridge, and cone-like some predictable influences from the generation of activity. Cone-like activity may represent eruptions that this volume of meltwater. First, thermal calculations produce local to regional tephra blankets that could be a show that a transient subglacial lake should form substantial source of glacial debris and serve as agents of down-slope of the advancing lava flow. Shallow direct heating and melting (hot airfall deposits) or lakes would rapidly refreeze, but the volumes albedo-induced melting (blanketing dark tephra). We generated here could lead to additional consequences. model a hypothetical set of cones based on composite For example, volumetrically significant local observations. We locate the cones along a 40 km long subglacial magmatic melting (such as calculated ridge beneath the Tharsis Montes tropical mountain here) could produce sufficient meltwater to cause a glacier ridged facies, interpreted to be drop moraines at local transition from cold-based to wet-based the outer, thinner part of the glacial system. The ridge is conditions, producing local wet-based surging of a interpreted to be the subglacial manifestation of a dike; portion of the otherwise cold-based glacier. the cones are interpreted to represent eruptive centers Evidence for such activity might be manifested in forming along wide places in the dike. We model the anomalous arcuate lobes of moraines downslope of cones as occupying a 6 km long segment of the ridge and the subglacial flows. In addition, drainage of the ranging from 600-1200 m in width, 600-1800 m in meltwater from beneath the glacier out into the length, and 150-280 m in height. Such cones are surrounding terrain could form local fluvial zones interpreted to represent eruptions into a melted cavity in ranging in scale from small channels up to the scale the ice or onto the glacier surface. Widths of such cones of jokulhlaups. Rapid drainage would be consistent are related to the ranges of ejected pyroclasts and imply with the survival of the released water against rapid explosive eruption speeds of ~ 40 m/s and magma water freezing in the low-temperature, low-atmospheric contents of ~0.1 wt %. If they were emplaced from dikes pressure martian environment. releasing magma at 1-10 cubic meters per second per In summary, we find that local sill-like subglacial meter along strike (a common rate on Earth), eruptions can produce sufficient meltwater to cause emplacement times would have been a few hours to 1-2 localized transitions from cold-based to wet-based days. Away from the cones, the ridge is modeled as ~ 60 glacial behavior, and produce related, and perhaps m high and ~250 m wide; here effusion rates would be catastrophic, drainage of meltwater. Studies are much smaller, ~0.004 cubic meters per second per meter underway to assess the relationships between the from a dike ~0.1 m wide. These values and this specific steep-sided
Load more

Recommended publications
  • The Hyaloclastite Ridge Formed in the Subglacial 1996 Eruption in Gjfilp, Vatnaj6kull, Iceland: Present Day Shape and Future Preservation
    The hyaloclastite ridge formed in the subglacial 1996 eruption in Gjfilp, Vatnaj6kull, Iceland: present day shape and future preservation M. T. GUDMUNDSSON, F. PALSSON, H. BJORNSSON & ~. HOGNADOTTIR Science Institute, University of Iceland, Hofsvallag6tu 53, 107 Reykjavik, Iceland (e-mail: [email protected]) Abstract: In the Gjfilp eruption in 1996, a subglacial hyaloclastite ridge was formed over a volcanic fissure beneath the Vatnaj6kull ice cap in Iceland. The initial ice thickness along the 6 km-long fissure varied from 550 m to 750 m greatest in the northern part but least in the central part where a subaerial crater was active during the eruption. The shape of the subglacial ridge has been mapped, using direct observations of the top of the edifice in 1997, radio echo soundings and gravity surveying. The subglacial edifice is remarkably varied in shape and height. The southern part is low and narrow whereas the central part is the highest, rising 450 m above the pre-eruption bedrock. In the northern part the ridge is only 150-200m high but up to 2kin wide, suggesting that lateral spreading of the erupted material occurred during the latter stages of the eruption. The total volume of erupted material in Gj~tlp was about 0.8 km 3, mainly volcanic glass. The edifice has a volume of about 0.7 km 3 and a volume of 0.07 km 3 was transported with the meltwater from Gj~lp and accumulated in the Grimsv6tn caldera, where the subglacial lake acted as a trap for the sediments. This meltwater-transported material was removed from the southern part of the edifice during the eruption.
    [Show full text]
  • Ice Core Drilling and Subglacial Lake Studies on the Temperate Ice Caps in Iceland
    Ice core drilling and subglacial lake studies on the temperate ice caps in Iceland Iceland astride the Mid-Atlantic ridge Lecture # 36 Astrobiology Winter School Ice drilling projects in Iceland University of Hawaii, Jan. 2005 Thorsteinn Thorsteinsson ([email protected]) National Energy Authority Ice cover during the late glacial period. Combination of hot spot volcanism, spreading on the Mid-Atlantic ridge and glaciation leads to unusual geology. From Thordarson and Höskuldsson (2003). Subglacial volcanism beneath an ice sheet creates unusual landforms: Tuyas (tablemountains) and ridges. Herðubreið, N-Iceland Submarine eruptions create similar formations. Biologicial colonization monitored from the beginning Surtsey eruption, S. of Iceland, 1963-1967. Recent subglacial eruption in Grímsvötn, Vatnajökull ice cap. Jökulsárgljúfur canyons, N. Iceland: Formed in a catastrophic flood from Vatnajökull 2500 years ago. Icelandic analogs to hillside gullies on Mars Mars Mars Iceland Iceland Iceland Temperate ice caps Hofsjökull, 890 km2 cover >10% of Iceland Vatnajökull 2 Langjökull 8000 km 2 920 km Max. thickness: 950 m Mýrdalsjökull 550 km2 - Dynamic ice caps in a maritime climate. - High accumulation rates (2-4 m w.eq. yr-1) - Extensive melting during summer, except at highest elevations (> 1800 m) - Mass balance of ice caps negative since 1995 1972: A 415 m ice core was drilled on the NW-part of Vatnajökull Activities not continued at that time, drill was discarded. Mass balance of Hofsjökull Ice Cap 4 2 0 Winter balance -2 Summer balance H2O Net balance m -4 Cumulative mass balance -6 -8 -10 1987 1992 1997 2002 Climate, Water, Energy: A research project investigating the effect of climate change on energy production in the Nordic countries Temperature increase 1990-2050 °C CWE uses IPCC data to create scenarios for temperature and precipitation change in the Nordic region in the future Modelled change in volume of Hofsjökull ice cap 2000-2002, Modelled glacial meltwater using four different dT and dP discharge (run-off) 2000-2200.
    [Show full text]
  • Evidence for Extending Anomalous Miocene Volcanism at the Edge of The
    1 Evidence for Extending Anomalous Miocene Volcanism at the Edge of the 2 East Antarctic Craton 3 4 K. J. Licht1, T. Groth1, J. P. Townsend2, A. J. Hennessy1, S. R. Hemming3, T. P. Flood4, and M. 5 Studinger5 6 1Department of Earth Sciences, Indiana University-Purdue University Indianapolis, Indianapolis, IN, 7 USA, 2HEDP Theory Department, Sandia National Laboratories, Albuquerque, NM, USA, 3Department of 8 Earth and Environmental Sciences, Columbia University, Lamont-Doherty Earth Observatory, Palisades, 9 NY, USA, 4Geology Department, St. Norbert College, DePere, WI, USA, 5NASA Goddard Space Flight 10 Center, Greenbelt, MD, USA 11 12 Corresponding author: Kathy Licht ([email protected]) 13 14 Key Points: 15 x Olivine basalt, hyaloclastite erratics and detrital zircon at Earth’s southernmost moraine 16 (Mt. Howe) indicate magmatic activity 17- 25 Ma. 17 x The source, indicated by a magnetic anomaly (-740 nT) ~400 km inland from the West 18 Antarctic Rift margin, expands extent of Miocene lavas. 19 x Data corroborate lithospheric foundering beneath southern Transantarctic Mountains based 20 on location of volcanism (duration < 5 my). 21 22 Abstract 23 Using field observations followed by petrological, geochemical, geochronological, and 24 geophysical data we infer the presence of a previously unknown Miocene subglacial volcanic 25 center ~230 km from the South Pole. Evidence of volcanism is from boulders of olivine-bearing 26 amygdaloidal/vesicular basalt and hyaloclastite deposited in a moraine in the southern 27 Transantarctic Mountains. 40Ar/39Ar ages from five specimens plus U-Pb ages of detrital zircon 28 from glacial till indicate igneous activity 25-17 Ma.
    [Show full text]
  • EGU2015-13634-4, 2015 EGU General Assembly 2015 © Author(S) 2015
    Geophysical Research Abstracts Vol. 17, EGU2015-13634-4, 2015 EGU General Assembly 2015 © Author(s) 2015. CC Attribution 3.0 License. High-precision mapping of seismicity in the 2014 Bárdarbunga volcanic episode Kristín S. Vogfjörd, Martin Hensch, Gunnar B. Gudmundsson, and Kristín Jónsdóttir Icelandic Meteorological Office, Reykjavik, Iceland ([email protected]) The Bárdarbunga volcano and its associated fissure swarm in Iceland’s Eastern volcanic zone is a highly active system with over 20 eruptions in the last 11 centuries. The location of this active volcano and much of the fissure swarm under several hundred metres thick ice gives rise to multiple hazards, including explosive, subglacial eruptions and associated subglacial floods (jökulhlaups), as well as fissure eruptions extruding large volumes of lava. After a decade of increasing seismic activity, volcanic unrest at Bárdarbunga suddenly escalated into a minor subglacial eruption on 16 August 2014. In the following weeks seismic activity soared and surface defor- mation of tens of cm were observed, caused by rifting and a dyke intrusion, which propagated 48 km northward from the central volcano (Sigmundsson et al., 2014). The dyke propagation stopped just outside the glacial margin and ended in a fissure eruption at Holuhraun at the end of August. At the time of writing the eruption is ongoing, having extruded a lava volume of over 1 km3 and released high rates of SO2 into the atmosphere. Over twenty thousand microearthquakes have been recorded. Initially most were in the dyke, but after the first two weeks the activity around the caldera rim increased and over 70 shallow earthquakes with MW > 5 have been located along the caldera rim accompanied by caldera subsidence.
    [Show full text]
  • Subglacial to Emergent Volcanism at Shield Nunatak, Mt. Melbourne Volcanic Field, Antarctica
    Polarforschung 57 1/2: 27-41, 1987 Subglacial to Emergent Volcanism at Shield Nunatak, Mt. Melbourne Volcanic Field, Antarctica By G. Wörner and L. Viereck* Summary: Sections through Shield Nunatak vo1cano, an alkali basaltic subglacial table-mountain from the Mt. Melbourne Volcanic Field, are descrlbed. Resting on a base of older lava flows and a fossile tillite iayer, the volcano is formed mainly by massive ash and lapilli (mass flow) deposits while pillow lavas are absent. The recurrent stage of emergence from subglacial to subaerial conditions is characterized by de­ velopment of tuff rings from explosive interaction between magma and melt water, complex ash- and lapilli deposits, including lava flows brecciated by water-interaction and a subaerial basaltie ash-flow deposit. The sequence is capped by subaerial tuff rings, lava flows, scoria cones and reworked tephra. Available data on subaquatlc explosive voJcanism indicate that early Shield Nunatak basaltic lavas erupted un­ der less than 300 m of ice cover: later Iavas erupted under shallow-water and subaerial conditions. Shield Nunatak probably formed during a glacial period (possibly the last) when the ice thtckness in the Mt. Melbourne area must have been at least 200 m greater than at present. The volcano has suffered only minor glacial erosion and still almost has its original shape. Zusammenfassung: Es werden Profile beschrieben durch einen alkalibasaltischen subglazialen Vulkan (Shield Nunatak) im Mt. Melbourne Vulkanfeld. Die Unterlage des Vulkans wird von einer Serie subaerischer Lavaströme intermediärer Zusammensetzung (Mugearit) gebildet. Über einer Lage von Paleo-Till bilden massive Aschenablagerungen die Basis der subglazialen Sequenz. Kissenlaven fehlen.
    [Show full text]
  • Timeline Reconstruction of Holocene Jökulhlaups Along the Jökulsá Á
    Copyright by Greta Hoe Wells 2016 The Thesis Committee for Greta Hoe Wells Certifies that this is the approved version of the following thesis: Timeline Reconstruction of Holocene Jökulhlaups along the Jökulsá á Fjöllum Channel, Iceland APPROVED BY SUPERVISING COMMITTEE: Supervisor: Sheryl Luzzadder-Beach Timothy P. Beach Daene C. McKinney Timeline Reconstruction of Holocene Jökulhlaups along the Jökulsá á Fjöllum Channel, Iceland by Greta Hoe Wells, B.A. Thesis Presented to the Faculty of the Graduate School of The University of Texas at Austin in Partial Fulfillment of the Requirements for the Degree of Master of Arts The University of Texas at Austin May 2016 Abstract Timeline Reconstruction of Holocene Jökulhlaups along the Jökulsá á Fjöllum Channel, Iceland Greta Hoe Wells, M.A. The University of Texas at Austin, 2016 Supervisor: Sheryl Luzzadder-Beach The Jökulsá á Fjöllum is Iceland’s second longest river, draining from the Vatnajökull ice cap and winding for over 200 km through the eastern highlands before emptying into the Arctic Ocean. Hydrothermal activity and subglacial eruptions beneath Vatnajökull generate enormous quantities of meltwater, which can drain catastrophically in outburst floods, known as jökulhlaups. Jökulhlaups have flowed through the Jökulsá á Fjöllum channel throughout the Holocene, but intense debate exists over their timing and magnitude. While previous studies report a peak flood discharge of 0.9 x 106 m3 s-1, Howard et al. (2012) found evidence of a peak discharge of 2.2 x 107 m3 s-1, which would make this the largest known flood on Earth. This project seeks to test Howard et al.’s (2012) hypothesis and, more broadly, to reconstruct a timeline of Holocene jökulhlaups iv along the Jökulsá á Fjöllum.
    [Show full text]
  • The Mechanics of Subglacial Basaltic Lava Flow Emplacement: Inferring Paleo-Ice Conditions
    THE MECHANICS OF SUBGLACIAL BASALTIC LAVA FLOW EMPLACEMENT: INFERRING PALEO-ICE CONDITIONS by Jefferson D. G. Hungerford B. S. in Geology, University of Washington, 2002 Submitted to the Graduate Faculty of The Kenneth P. Dietrich School of Arts and Sciences in partial fulfillment of the requirements for the degree of Doctor of Philosophy University of Pittsburgh 2013 UNIVERSITY OF PITTSBURGH FACULTY OF THE KENNETH P. DIETRICH SCHOOL OF ARTS AND SCIENCES This dissertation was presented by Jefferson D. G. Hungerford It was defended on November 8, 2013 and approved by Dr. William Harbert, Professor, Department of Geology and Planetary Science Dr. Thomas A. Anderson, Professor Emeritus, Department of Geology and Planetary Science Dr. Daniel J. Bain, Assistant Professor, Department of Geology and Planetary Science Dr. Tracy K. P. Gregg, Associate Professor, Department of Geology, University at Buffalo Dissertation Advisor: Dr. Michael S. Ramsey, Professor, Department of Geology and Planetary Science ii Copyright © by Jefferson D. G. Hungerford 2013 iii THE MECHANICS OF SUBGLACIAL BASALTIC LAVA FLOW EMPLACEMENT: INFERRING PALEO-ICE CONDITIONS Jefferson D. G. Hungerford, PhD University of Pittsburgh, 2013 Recent studies of terrestrial glaciovolcanic terrains have elucidated the utility of volcanic deposits as recorders of ice conditions at the time of eruption. Practically all of these investigations, however, have focused upon the associations of volcaniclastic and coherent lava lithofacies at or proximal to the source vent. Very few studies have documented the emplacement of effusion-dominated, basaltic glaciovolcanic eruptions and their distal deposits that more accurately reveal paleo-ice conditions. Both Mauna Kea volcano, Hawaii and the Tennena volcanic center (TVC), on Mount Edziza, British Columbia, Canada, preserve records of interaction between coherent lavas and an ice sheet inferred to be associated with the last glacial maximum (LGM).
    [Show full text]
  • Origin Ofenigmatic Hills in the Ross Sea, Antarctica
    Origin ofEnigmatic Hills in the Ross Sea, Antarctica A Senior Thesis Submitted in Partial Fulfillment ofthe Requirements for graduation with a Bachelor ofScience in the School ofEarth Sciences at The Ohio State University by William R. Magee The Ohio State University June 2009 Project Advisor: Terry J. Wilson, School ofEarth Sciences Approved by Terry J. Wi son Acknowledgments I would like to thank Terry Wilson for her unprecedented guidance and advice throughout this entire research project. I give thanks to all ofwhom participated in the NBP04-01 geophysical research cruise. To my parents, brothers, and relatives who have always supported me during my entire undergraduate career. This work would also not be possible without the assistance of Stephanie Konfal, Cristina Millan, and Jamey Stutz. Table of Contents Introduction 1 Geologic Setting The Antarctic Plate........•.•.....•........•.•....•.•.......•....•.....••...•.....•......••.•.....2 West Antarctic Rift System 2 Rift Structure Beneath the Western Ross Sea...•..••............••........••..•...••.........4 Antarctic Plate Volcanic History 4 Erebus and Melbourne Volcanic Provinces in the Western Ross Sea Region 5 Ice Sheet History 10 Establishing the Origin of the Seafloor Hills Hypotheses for the Origin ofthe Enigmatic Seafloor Hills 12 Approach to Testing Hypothesis 12 Drumlin Morphology 14 Tuya Morphology 15 Summary 20 Bathymetric Data 21 Results Dimensions ofthe Seafloor Hills•....••......•........•.•...•••.........•........•..•......•.•.27 Shapes ofthe Seafloor Hills in Profile 30 Shapes ofthe Seafloor Hills in Map View 31 Discussion Seafloor Hills Origin 35 Ice Sheet History 36 Conclusions 40 References Introduction Antarctica is an isolated part of this planet, yet the history of this continent and its ice sheets is of global importance. The structural deformation, volcanism, and ice sheet history of the continent can be reconstructed through geological studies of surface topography and subsurface architecture.
    [Show full text]
  • World Heritage Volcanoes a Thematic Study
    World Heritage Convention IUCN World Heritage Studies 2009 Number 8 World Heritage Volcanoes A Thematic Study IUCN Programme on Protected Areas A Global Review of Volcanic World Heritage Properties: Present Situation, Future Prospects and Management Requirements IUCN, International Union for Conservation of Nature Founded in 1948, IUCN brings together States, government agencies and a diverse range of non-govern- mental organizations in a unique world partnership: over 1000 members in all spread across some 140 countries. As a Union, IUCN seeks to infl uence, encourage and assist societies throughout the world to conserve the integrity and diversity of nature and to ensure that any use of natural resources is equitable and ecologically sustainable. A central Secretariat coordinates the IUCN Programme and serves the Union membership, representing their views on the world stage and providing them with the strategies, services, scientifi c knowl- edge and technical support they need to achieve their goals. Through its six Commissions, IUCN draws together over 10,000 expert volunteers in project teams and ac- tion groups, focusing in particular on species and biodiversity conservation and the management of habitats and natural resources. The Union has helped many countries to prepare National Conservation Strategies, and demonstrates the application of its knowledge through the fi eld projects it supervises. Operations are increasingly decentralized and are carried forward by an expanding network of regional and country offi ces, located principally in developing countries. IUCN builds on the strengths of its members, networks and partners to enhance their capacity and to support global alliances to safeguard natural resources at local, regional and global levels.
    [Show full text]
  • Universities of Leeds, Sheffield and York
    promoting access to White Rose research papers Universities of Leeds, Sheffield and York http://eprints.whiterose.ac.uk/ This is the author’s pre-print version of an article published in the Journal of Volcanology and Geothermal Research White Rose Research Online URL for this paper: http://eprints.whiterose.ac.uk/id/eprint/76055 Published article: Cousins, CR, Crawford, IA, Harris, J, Carrivick, JL, Gunn, M, Kee, TP, Herschy, B, Karlsson, M, Carmody, L, Cockell, C and Joy, KH (2013) Glaciovolcanic hydrothermal environments in Iceland and implications for their detection on Mars. Journal of Volcanology and Geothermal Research, 256. 61 - 77. ISSN 0377-0273 http://dx.doi.org/10.1016/j.jvolgeores.2013.02.009 White Rose Research Online [email protected] Claire Cousins - BBK 14/08/12 Mars analogue volcano-ice hydrothermal environments at Kverkfjöll and Askja volcanoes, Iceland Cousins, C.R1,2., Gunn, M3., Crawford, I.A1,2., Carrivick, J.L4., Harris, J1,2., Kee, T.P5., Karlsson, M6., Thorsteinsson, T7., Carmody, L8., Herschy, B5., Ward, J.M9., Cockell, C10., Joy, K.H11., White, O.L12. 1Dept. Earth and Planetary Sciences, Birkbeck College, University of London, Malet Street, London, WC1E 6BT, UK. 2Centre for Planetary Sciences at UCL/Birkbeck, Gower Street, London, WC1E 6BT, UK. 3Institute for Mathematics and Physics, Aberystwyth University, Aberystwyth, SY23 3BZ, UK. 4School of Geography, Woodhouse Lane, University of Leeds, Leeds, LS2 9JT, UK. 5School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK. 6Magnus? Iceland. 7Thorstein? Iceland. 8Planetary Geoscience Institute, Earth and Planetary Sciences, University of Tennessee, Knoxville, TN, 37996, USA. 9Institute for Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, UK.
    [Show full text]
  • Forecasting and Monitoring a Subglacial Eruption in Iceland
    Eos, Vol. 86, No. 26, 28 June 2005 VOLUME 86 NUMBER 26 28 JUNE 2005 EOS, TRANSACTIONS, AMERICAN GEOPHYSICAL UNION PAGES 245–252 Monitoring Systems Forecasting and Monitoring a To monitor seismic and volcanic activity in Iceland, IMO operates a nationwide digital Subglacial Eruption in Iceland network of 44 seismic stations (network name: SIL) [Bödvarsson et al., 1999], six volumetric PAGES 245, 248 traveled ~50 km beneath the Skeidarárjökull borehole strain meters, and 16 continuous outlet glacier (Figure 1b). Jökulhlaups occur GPS stations (network name: ISGPS) (H. Geirs- The recognition of geophysical precursors there every 1–10 years and last from days to son et al., Current plate movements across to volcanic activity is a primary challenge weeks, each time releasing 0.4–4 km3 of water the Mid-Atlantic Ridge determined from 5 in volcano monitoring. That challenge was [Björnsson, 2002]. Volcanic eruptions in Gríms- years of continuous GPS measurements in successfully met by scientists at the Icelandic vötn often coincide with jökulhlaups. Iceland, submitted to Journal of Geophysical Meteorological Offi ce (IMO) before the 1 November 2004 eruption of Grímsvötn, a subglacial volcano beneath the Vatnajökull ice cap, Iceland (Figure 1). Seismic and geodetic precursors were prop- erly recognized, leading to a timely eruption forecast and warning announcements. During the eruption, IMO’s monitoring capability was greatly expanded by employing geophysical and meteorological observation tools, which enabled real-time hazard assessment. Hazards arising from subglacial volcanism are due mainly to the explosive effects of magma-ice interaction, which generates a tephra-laden plume of steam that ascends rap- idly into the upper atmosphere.
    [Show full text]
  • View Entire Issue
    Vol. 12, No. 1 A Publication of the Geological Society of America January 2002 Inside This Issue Eocene Meridional Weather Patterns Reflected in the Oxygen Isotopes of Arctic Fossil Wood A. Hope Jahren and Leonel Silveira Lobo Sternberg, p. 4 Section Meetings: North–Central and Southeastern, p. 20 South–Central, p. 26 Introducing the ZSX XRF Spectrometer Series from • Extra thin Rh end window tube for superior light element performance • 500 micron spot size • Mapping capabilities • Small sample analysis • Application wizards • X-Y sample stage For more information contact Rigaku at: 9009 New Trails Drive • The Woodlands, Texas 77381 Web: www.rigaku.com Phone: 281-363-1033 • Fax: 281-364-3628 E-mail: [email protected] Contents GSA TODAY (ISSN 1052-5173) is published monthly by The Geological Vol. 12, No. 1 January 2002 Society of America, Inc., with offices at 3300 Penrose Place, Boulder, Colorado. Mailing address: P.O. Box 9140, Boulder, CO 80301-9140, U.S.A. Periodicals postage paid at Boulder, Colorado, and at additional mailing science article offices. Postmaster: Send address changes to GSA Today, Member Services, P.O. Box 9140, Boulder, CO 80301-9140. Eocene Meridional Weather Patterns Reflected Copyright © 2002, The Geological Society of America, Inc. (GSA). All rights 4 reserved. Copyright not claimed on content prepared wholly by U.S. in the Oxygen Isotopes of Arctic Fossil Wood . government employees within scope of their employment. Individual scientists A. Hope Jahren and Leonel Silveira Lobo Sternberg are hereby granted permission, without fees or further requests to GSA, to use a single figure, a single table, and/or a brief paragraph of text in other subsequent works and to make unlimited photocopies of items in this journal for noncommercial use in classrooms to further education 10 and science.
    [Show full text]