A Recent Volcanic Eruption in West Antarctica
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Region 19 Antarctica Pg.781
Appendix B – Region 19 Country and regional profiles of volcanic hazard and risk: Antarctica S.K. Brown1, R.S.J. Sparks1, K. Mee2, C. Vye-Brown2, E.Ilyinskaya2, S.F. Jenkins1, S.C. Loughlin2* 1University of Bristol, UK; 2British Geological Survey, UK, * Full contributor list available in Appendix B Full Download This download comprises the profiles for Region 19: Antarctica only. For the full report and all regions see Appendix B Full Download. Page numbers reflect position in the full report. The following countries are profiled here: Region 19 Antarctica Pg.781 Brown, S.K., Sparks, R.S.J., Mee, K., Vye-Brown, C., Ilyinskaya, E., Jenkins, S.F., and Loughlin, S.C. (2015) Country and regional profiles of volcanic hazard and risk. In: S.C. Loughlin, R.S.J. Sparks, S.K. Brown, S.F. Jenkins & C. Vye-Brown (eds) Global Volcanic Hazards and Risk, Cambridge: Cambridge University Press. This profile and the data therein should not be used in place of focussed assessments and information provided by local monitoring and research institutions. Region 19: Antarctica Description Figure 19.1 The distribution of Holocene volcanoes through the Antarctica region. A zone extending 200 km beyond the region’s borders shows other volcanoes whose eruptions may directly affect Antarctica. Thirty-two Holocene volcanoes are located in Antarctica. Half of these volcanoes have no confirmed eruptions recorded during the Holocene, and therefore the activity state is uncertain. A further volcano, Mount Rittmann, is not included in this count as the most recent activity here was dated in the Pleistocene, however this is geothermally active as discussed in Herbold et al. -
Surface Exposure Dating Using Cosmogenic
Surface exposure dating using cosmogenic isotopes: a field campaign in Marie Byrd Land and the Hudson Mountains Joanne S Johnson1, Karsten Gohl2, Terry L O’Donovan1, Mike J Bentley3,1 1British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 OET, UK 2Alfred Wegener Institute, Postfach 120161, D-27515, Bremerhaven, Germany 3Durham University, South Road, Durham, DH1 3LE, UK INTRODUCTION SUMMARY 2. HUNT BLUFF Here we present preliminary findings from fieldwork undertaken in Marie • We collected 7 erratic and 2 bedrock surface samples, which are Byrd Land and western Ellsworth Land (Fig.1) in March 2006, during This site is a granite outcrop along currently being processed for 10Be, 26Al and 3He dating. We will visit which we obtained samples for surface exposure dating. This work was the western side of Bear the Hudson Mountains again in 2007/8 for further sampling and supported by helicopters from RV Polarstern, on an expedition to Pine Peninsula, adjacent to the Dotson collection of geomorphological data. Island Bay. Ice Shelf. Lopatin et al. (1974) report an age of 301 Ma for the • Samples from Turtle Rock, Mt Manthe and the un-named island are Surface exposure dating provides an estimate of the time when ice granite. granite/granitoids; from Hunt Bluff we collected a meta-sandstone and retreated from a rock surface, leaving it exposed. Nucleii in rocks are basalt, in addition to granite bedrock. split apart by neutrons produced when secondary cosmic rays enter the In half a day, we found only a few • Erratic boulders at Mt Manthe and Hunt Bluff are scarce; at Turtle atmosphere. -
Weather and Climate in the Amundsen Sea Embayment
WEATHER AND CLIMATE IN THE AMUNDSEN SEA EMBAYMENT,WEST ANTARCTICA:OBSERVATIONS, REANALYSES AND HIGH RESOLUTION MODELLING A thesis submitted to the School of Environmental Sciences of the University of East Anglia in partial fulfilment of the requirements for the degree of Doctor of Philosophy RICHARD JONES JANUARY 2018 © This copy of the thesis has been supplied on condition that anyone who consults it is understood to recognise that its copyright rests with the author and that use of any information derived there from must be in accordance with current UK Copyright Law. In addition, any quotation or extract must include full attribution. © Copyright 2018 Richard Jones iii ABSTRACT Glaciers within the Amundsen Sea Embayment (ASE) are rapidly retreating and so contributing 10% of current global sea level rise, primarily through basal melting. » Here the focus is atmospheric features that influence the mass balance of these glaciers and their representation in atmospheric models. New radiosondes and surface-based observations show that global reanalysis products contain relatively large biases in the vicinity of Pine Island Glacier (PIG), e.g. near-surface temperatures 1.8 ±C (ERA-I) to 6.8 ±C (MERRA) lower than observed. The reanalyses all underestimate wind speed during orographically-forced strong wind events and struggle to reproduce low-level jets. These biases would contribute to errors in surface heat fluxes and thus the simulated supply of ocean heat leading to PIG melting. Ten new ice cores show that there is no significant trend in accumulation on PIG between 1979 and 2013. RACMO2.3 and four global reanalysis products broadly reproduce the observed time series and the lack of any significant trend. -
Previously Unsuspected Volcanic Activity Confirmed Under West Antarc…Ice Sheet at Pine Island Glacier | NSF - National Science Foundation 1/30/20, 9 08 AM
Previously unsuspected volcanic activity confirmed under West Antarc…Ice Sheet at Pine Island Glacier | NSF - National Science Foundation 1/30/20, 908 AM Home (/) › News (/news/) News Release 18-044 Previously unsuspected volcanic activity confirmed under West Antarctic Ice Sheet at Pine Island Glacier Potential effects of volcanic warming on ice-sheet melting and sea level rise still to be determined The Pine Island Glacier meets the ocean. Credit and Larger Version (/news/news_images.jsp?cntn_id=295861&org=NSF) June 27, 2018 This material is available primarily for archival purposes. Telephone numbers or other contact information may be out of date; please see current contact information at media contacts (/staff/sub_div.jsp? org=olpa&orgId=85). https://www.nsf.gov/news/news_summ.jsp?cntn_id=295861 Page 1 of 4 Previously unsuspected volcanic activity confirmed under West Antarc…Ice Sheet at Pine Island Glacier | NSF - National Science Foundation 1/30/20, 908 AM Tracing a chemical signature of helium in seawater, an international team of scientists funded by the National Science Foundation (NSF) and the United Kingdom's (U.K.) Natural Environment Research Council (NERC) has discovered a previously unknown volcanic hotspot beneath the massive West Antarctic Ice Sheet (WAIS). Researchers say the newly discovered heat source could contribute in ways yet unknown to the potential collapse of the ice sheet. The scientific consensus is that the rapidly melting Pine Island Glacier, the focal point of the study, would be a significant source of global sea level rise should the melting there continue or accelerate. Glaciers such as Pine Island act as plugs that regulate the speed at which the ice sheet flows into the sea. -
A Review of Ice-Sheet Dynamics in the Pine Island Glacier Basin, West Antarctica: Hypotheses of Instability Vs
Pine Island Glacier Review 5 July 1999 N:\PIGars-13.wp6 A review of ice-sheet dynamics in the Pine Island Glacier basin, West Antarctica: hypotheses of instability vs. observations of change. David G. Vaughan, Hugh F. J. Corr, Andrew M. Smith, Adrian Jenkins British Antarctic Survey, Natural Environment Research Council Charles R. Bentley, Mark D. Stenoien University of Wisconsin Stanley S. Jacobs Lamont-Doherty Earth Observatory of Columbia University Thomas B. Kellogg University of Maine Eric Rignot Jet Propulsion Laboratories, National Aeronautical and Space Administration Baerbel K. Lucchitta U.S. Geological Survey 1 Pine Island Glacier Review 5 July 1999 N:\PIGars-13.wp6 Abstract The Pine Island Glacier ice-drainage basin has often been cited as the part of the West Antarctic ice sheet most prone to substantial retreat on human time-scales. Here we review the literature and present new analyses showing that this ice-drainage basin is glaciologically unusual, in particular; due to high precipitation rates near the coast Pine Island Glacier basin has the second highest balance flux of any extant ice stream or glacier; tributary ice streams flow at intermediate velocities through the interior of the basin and have no clear onset regions; the tributaries coalesce to form Pine Island Glacier which has characteristics of outlet glaciers (e.g. high driving stress) and of ice streams (e.g. shear margins bordering slow-moving ice); the glacier flows across a complex grounding zone into an ice shelf coming into contact with warm Circumpolar Deep Water which fuels the highest basal melt-rates yet measured beneath an ice shelf; the ice front position may have retreated within the past few millennia but during the last few decades it appears to have shifted around a mean position. -
What If Antarctica's Volcanoes Erupt
What if Antarctica's dormant, ice-covered volcanoes wake up? John Smellie, Department of Geology, University of Leicester (This article was originally published in The Conversation, on 4 September 2017 [https://theconversation.com/what-if-antarcticas-dormant-ice-covered-volcanoes-wake-up-83450]) Antarctica is a vast icy wasteland covered by the world’s largest ice sheet. This ice sheet contains about 90% of fresh water on the planet. It acts as a massive heat sink and its meltwater drives the world’s oceanic circulation. Its existence is therefore a fundamental part of Earth’s climate. Less well known is that Antarctica is also host to several active volcanoes, part of a huge "volcanic province" which extends for thousands of kilometres along the Western edge of the continent. Although the volcanic province has been known and studied for decades, recently about 100 "new" volcanoes were recently discovered beneath the ice by scientists who used satellite data and ice- penetrating radar to search for hidden peaks. These sub-ice volcanoes may be dormant. But what would happen if Antarctica’s volcanoes awoke? IMAGE: Some of the volcanoes known about before the latest discovery. Source: antarcticglaciers.org (image: JL Smellie) We can get some idea by looking to the past. One of Antarctica’s volcanoes, Mount Takahe, is found close to the remote centre of the West Antarctic Ice Sheet. In a new study, scientists implicate Takahe in a series of eruptions rich in ozone-consuming halogens that occurred about 18,000 years ago. These eruptions, they claim, triggered an ancient ozone hole, warmed the southern hemisphere causing glaciers to melt, and helped bring the last ice age to a close. -
Basal Crevasses on the Larsen C Ice Shelf, Antarctica
GEOPHYSICAL RESEARCH LETTERS, VOL. 39, L16504, doi:10.1029/2012GL052413, 2012 Basal crevasses on the Larsen C Ice Shelf, Antarctica: Implications for meltwater ponding and hydrofracture Daniel McGrath,1 Konrad Steffen,1 Harihar Rajaram,2 Ted Scambos,3 Waleed Abdalati,1,4 and Eric Rignot5,6 Received 1 June 2012; revised 20 July 2012; accepted 23 July 2012; published 29 August 2012. [1] A key mechanism for the rapid collapse of both the Lar- thickness (due to the density difference between water and sen A and B Ice Shelves was meltwater-driven crevasse ice), fracturing the ice shelf into numerous elongate icebergs propagation. Basal crevasses, large-scale structural features [van der Veen, 1998, 2007; Scambos et al., 2003, 2009; within ice shelves, may have contributed to this mechanism in Weertman, 1973]. The narrow along-flow width and elon- three important ways: i) the shelf surface deforms due to gated across-flow length of these icebergs distinguishes them modified buoyancy and gravitational forces above the basal from tabular icebergs, and likely facilitates a positive feed- crevasse, creating >10 m deep compressional surface depres- back during the disintegration process, as elongate icebergs sions where meltwater can collect, ii) bending stresses from overturn and initiate further ice shelf calving [MacAyeal the modified shape drive surface crevassing, with crevasses et al., 2003; Guttenberg et al., 2011; Burton et al., 2012]. reaching 40 m in width, on the flanks of the basal-crevasse- [3] Dramatic atmospheric warming over the past five dec- induced trough and iii) the ice thickness is substantially ades has increased surface meltwater production along the reduced, thereby minimizing the propagation distance before a Antarctic Peninsula (AP) [Vaughan et al.,2003;van den full-thickness rift is created. -
Thurston Island
RESEARCH ARTICLE Thurston Island (West Antarctica) Between Gondwana 10.1029/2018TC005150 Subduction and Continental Separation: A Multistage Key Points: • First apatite fission track and apatite Evolution Revealed by Apatite Thermochronology ‐ ‐ (U Th Sm)/He data of Thurston Maximilian Zundel1 , Cornelia Spiegel1, André Mehling1, Frank Lisker1 , Island constrain thermal evolution 2 3 3 since the Late Paleozoic Claus‐Dieter Hillenbrand , Patrick Monien , and Andreas Klügel • Basin development occurred on 1 2 Thurston Island during the Jurassic Department of Geosciences, Geodynamics of Polar Regions, University of Bremen, Bremen, Germany, British Antarctic and Early Cretaceous Survey, Cambridge, UK, 3Department of Geosciences, Petrology of the Ocean Crust, University of Bremen, Bremen, • ‐ Early to mid Cretaceous Germany convergence on Thurston Island was replaced at ~95 Ma by extension and continental breakup Abstract The first low‐temperature thermochronological data from Thurston Island, West Antarctica, ‐ fi Supporting Information: provide insights into the poorly constrained thermotectonic evolution of the paleo Paci c margin of • Supporting Information S1 Gondwana since the Late Paleozoic. Here we present the first apatite fission track and apatite (U‐Th‐Sm)/He data from Carboniferous to mid‐Cretaceous (meta‐) igneous rocks from the Thurston Island area. Thermal history modeling of apatite fission track dates of 145–92 Ma and apatite (U‐Th‐Sm)/He dates of 112–71 Correspondence to: Ma, in combination with kinematic indicators, geological -
Inland Thinning of West Antarctic Ice Sheet Steered Along Subglacial Rifts
LETTER doi:10.1038/nature11292 Inland thinning of West Antarctic Ice Sheet steered along subglacial rifts Robert G. Bingham1, Fausto Ferraccioli2, Edward C. King2, Robert D. Larter2, Hamish D. Pritchard2, Andrew M. Smith2 & David G. Vaughan2 Current ice loss from the West Antarctic Ice Sheet (WAIS) interior is promoted where narrow rift basins associated with a accounts for about ten per cent of observed global sea-level rise1. northeasterly extension of the WARS connect to the ocean. Losses are dominated by dynamic thinning, in which forcings by Our data set comprises the first systematic radar survey of Ferrigno oceanic or atmospheric perturbations to the ice margin lead to an Ice Stream (FIS; 85u W, 74u S), a 14,000-km2 ice-drainage catchment accelerated thinning of ice along the coastline2–5. Although central clearly identified by satellite altimetry as the most pronounced to improving projections of future ice-sheet contributions to global ‘hotspot’ of dynamic thinning along the Bellingshausen Sea margin sea-level rise, the incorporation of dynamic thinning into models of the WAIS (Fig. 1b). Data were collected by over-snow survey has been restricted by lack of knowledge of basal topography and between November 2009 and February 2010, and supplemented by subglacial geology so that the rate and ultimate extent of potential airborne data collected by the US NASA Operation IceBridge WAIS retreat remains difficult to quantify. Here we report the programme in 2009. The only previous measurements of ice thickness discovery of a subglacial basin under Ferrigno Ice Stream up to across the entire 150 km 3 115 km catchment were a sparse set of 1.5 kilometres deep that connects the ice-sheet interior to the reconnaissance seismic and gravity spot-depths obtained 50 years Bellingshausen Sea margin, and whose existence profoundly affects previously along exploratory traverses, and a handful of airborne radar ice loss. -
Net Retreat of Antarctic Glacier Grounding Lines
1 Net retreat of Antarctic glacier grounding lines 2 Hannes Konrad1,2, Andrew Shepherd1, Lin Gilbert3, Anna E. Hogg1, 3 Malcolm McMillan1, Alan Muir3, Thomas Slater1 4 5 Affilitations 6 1Centre for Polar Observation and Modelling, University of Leeds, United Kingdom 7 2Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, 8 Germany 9 3Centre for Polar Observation and Modelling, University College London, United Kingdom 10 11 Grounding lines are a key indicator of ice-sheet instability, because changes in their 12 position reflect imbalance with the surrounding ocean and impact on the flow of inland 13 ice. Although the grounding lines of several Antarctic glaciers have retreated rapidly 14 due to ocean-driven melting, records are too scarce to assess the scale of the imbalance. 15 Here, we combine satellite altimeter observations of ice-elevation change and 16 measurements of ice geometry to track grounding-line movement around the entire 17 continent, tripling the coverage of previous surveys. Between 2010 and 2016, 22%, 3%, 18 and 10% of surveyed grounding lines in West Antarctica, East Antarctica, and at the 19 Antarctic Peninsula retreated at rates faster than 25 m/yr – the typical pace since the 20 last glacial maximum – and the continent has lost 1463 km2 ± 791 km2 of grounded-ice 21 area. Although by far the fastest rates of retreat occurred in the Amundsen Sea Sector, 22 we show that the Pine Island Glacier grounding line has stabilized - likely as a 1 23 consequence of abated ocean forcing. On average, Antarctica’s fast-flowing ice streams 24 retreat by 110 meters per meter of ice thinning. -
Paleomagnetic Investigations in the Ellsworth Land Area, Antarctica
eastern half consists of gneiss (some banded), amphi- probably have mafic dikes as well as felsite dikes, are bolite, metavolcanics, granodiorite, diorite, and present. In the eastern part of the island, mafic dikes gabbro. Contacts are rare, and the relative ages of occur in banded gneiss. A dio rite- to-gabbroic mass is these rock bodies are in doubt. The Morgan Inlet present in the north central portion of the island. gneiss may represent the oldest rock on Thurston Granite-to-diorite bodies occur in the south central Island; earlier work (Craddock et al.. 1964) gave a portion of the island and contain "meta-volcanic" Rb-Sr age of 280 m.y. on biotite from this rock. rocks and mafic dikes. Granite-granodiorite-to-diorite Studies in the Jones Mountains were mainly on the rocks occur in the western portion of the island. This unconformity between the basement complex and the latter plutonic mass is probably the youngest body in overlying basaltic volcanic rocks to evaluate the evi- which mafic dikes are also present. About 10 miles dence for Tertiary glaciation. Volcanic strata just southwest of Thurston Island, a medium-grained above the unconformity contain abundant glass and granodiorite plutonic mass forms Dustin Island, pillow-like masses suggestive of interaction between where three samples were collected at Ehlers Knob. lava and ice. Tillites with faceted and striated exotic In the Jones Mountains, 27 oriented samples were pebbles and boulders are present in several localities collected from the area around Pillsbury Tower, on in the lower 10 m of the volcanic sequence. -
An Inventory of Subglacial Volcanoes in West Antarctica
Downloaded from http://sp.lyellcollection.org/ by guest on September 24, 2021 A new volcanic province: an inventory of subglacial volcanoes in West Antarctica MAXIMILLIAN VAN WYK DE VRIES*, ROBERT G. BINGHAM & ANDREW S. HEIN School of GeoSciences, University of Edinburgh, Drummond Street, Edinburgh EH8 9XP, UK *Correspondence: [email protected] Abstract: The West Antarctic Ice Sheet overlies the West Antarctic Rift System about which, due to the comprehensive ice cover, we have only limited and sporadic knowledge of volcanic activity and its extent. Improving our understanding of subglacial volcanic activity across the province is important both for helping to constrain how volcanism and rifting may have influenced ice-sheet growth and decay over previous glacial cycles, and in light of concerns over whether enhanced geo- thermal heat fluxes and subglacial melting may contribute to instability of the West Antarctic Ice Sheet. Here, we use ice-sheet bed-elevation data to locate individual conical edifices protruding upwards into the ice across West Antarctica, and we propose that these edifices represent subglacial volcanoes. We used aeromagnetic, aerogravity, satellite imagery and databases of confirmed volca- noes to support this interpretation. The overall result presented here constitutes a first inventory of West Antarctica’s subglacial volcanism. We identified 138 volcanoes, 91 of which have not previ- ously been identified, and which are widely distributed throughout the deep basins of West Antarc- tica, but are especially concentrated and orientated along the >3000 km central axis of the West Antarctic Rift System. Gold Open Access: This article is published under the terms of the CC-BY 3.0 license.