Expressions of Intent for International Polar Year 2007-2008 Activities

Expression of Interest Details

PROPOSAL INFORMATION

Geodynamics of the West Antarctic Rift System (WARS) in Remote Ellsworth Land and its implications for the stability of the West Antarctic Ice Sheet  (West Antarctic Rift System (WARS) in Remote Ellsworth Land)

Outline
The aim of the proposed project is to test the model that the West Antarctic Rift System (WARS) is a horse tail structure due to movement of the Marie Byrd Land microplate / Thurston Island block away from Victoria Land to the NE (by 400 km in 100 Ma) (Behrendt and Cooper 1991, Luyendyk et al. 1996). While it is developed as extensional pull apart basin in the Ross Sea embayment it is proposed here that it is expressed as dextral strike slip fault system at its northeastern end in remote Ellsworth Land. Background Ross Sea embayment as well as Marie Byrd Land and its volcanics were studied in great detail over decades (Behrendt et al. 1991, Behrendt 1999, LeMasurier 1972, 1990, 2002, Rocchi et al. 2002). Only during the 1990s investigations of the subglacial geology were performed in restricted areas within the central WARS of the Subglacial Byrd Basin by the West Antarctic Ice Sheet Airborne Gravimetry Initiative, e. g. in the CASERTZ quadrangle as well as in the area of Ice Stream D draining into the Ross Ice Shelf (Behrendt et al. 1994, 1998, Bell et al. 1998, Blankenship et al. 1993). Additional information was gathered by more recent initiatives like the ANUBIS broadband seismic experiment (Winberry and Anandakrishnan 2004). The results of multi-disciplinary aerogeophysical surveys - that must be addressed as restricted with respect to the continental dimensions of the rift system - indicate that the southern boundary fault of WARS extends north of Whitmore Mts. towards Ellsworth Mts. (EWM) while a northern boundary fault cannot be identified clearly. The sedimentary basin with extensional horst and graben structures extends well into the Subglacial Byrd Basin and the basin is associated with active seismicity and volcanism, subglacial caldera structures indicate voluminous magmatic systems within upper crustal levels. Research Activities In order to test the model investigations are needed in Ellsworth Land, one of the least accessible and most poorly known areas in Antarctica. It stretches between Amundsen Sea, Ronne Ice Shelf and Bellingshausen Sea and encloses a triangle (see map) between Hudson Mts. at the Walgreen Coast, Sentinel Range in the Ellsworth Mountains and Eltanin Bay with the Rydberg Peninsula at the Bryan Coast. The focus of the research activities is a multi-disciplinary aerogeophysical survey within this triangle, including imaging of subglacial topography as well as the magnetic and gravity field. Ground based geoscience fieldwork studies include: . structural geology studies to check for indications of the regional stress field at the northern end of the Ellsworth Mts. (EWM); · seismic study with temporary broadband seismic stations · GPS measurements in the Hudson Mountains (e.g. on Webber Nunatak), at Eltanin Bay (altern. Mt. Tuve) as well as at the northern end of the Sentinel Range (e.g. Mt. Weems); · sampling for fission track dating to describe the exhumation history of individual geodynamic blocks as well as · sampling for paleomagnetic studies in order to reconstruct paleopositions · mapping and dating of hydroclastic eruptive features within the Bellingshausen Volcanic Provinc from Hudson Mts. in the West over Jones Mts. to Rydberg Peninsula at Bryan Coast in the East in order to deceiver ice sheet dynamics by reconstructing thicknesses of paleo-ice sheets; · geo- and mineralchemistry of volcanics and enclosed mantle and crustal xenoliths in order to describe variations in magma genesis including mantle source compositions, mantle melting regimes and differentiation during ascent through the lithosphere; additional fastdrilling might provide sampling of the subglacial geology The project can be initiated within the framework of the German mission to Pine Island Bay in the season 2005/06 by setting up a GPS reference point within the Hudson Mountains at Pine Island Bay as well as by initial volcanological and petrological field studies including dating the volcanic structures as well as identifying the point of an eruption recorded by satellites in the Hudson Mountain Volcanic Field in 1985, which is the closest to the fastest flowing glacier in Antarctica, the Pine Island Glacier. References BEHRENDT (1999) Global.Planet.Change 23, 25-44; BEHRENDT and COOPER (1991) Geology 19, 315-319; BEHRENDT et al. (1991) Tectonics 10, 1257-1273; BEHRENDT et al. (1994) Geology 22, 527-530; BEHRENDT et al. (1998) Geophys.Res.Lett. 25, 4385-4388; BELL et al. (1998) Nature 394, 58-62; BLANKENSHIP et al. (1993) Nature 361, 526-529; LEMASURIER (1972) Antarc.Geol.Geophys., 251-260; LEMASURIER (1990) AGU Antarc.Res.Ser. 48, 146-163; LEMASURIER (2002) Geol.Soc.Lond. Spec.Publ. 202, 115-148; Luyendyk et al. (1996) Tectonics 15, 122-141; ROCCHI et al. (2002) J.Geoph.Res. 107, B9, 2195, ECV 5; Winberry and Anandakrishnan (2004) Terra Nostra 4, 319-320.

What significant advance(s) in relation to the IPY themes and targets can be anticipated from this project?
We will know (1) the geodynamic status of the transcontinental WARS and thus the present “environmental status” of West Antarctica, e.g. the tectonic mobility, the potential for seismic activity, and especially of subglacial volcanic activity as source for a hydrothermal potential that may influence the mobility of the West Antarctic Ice Sheet; the project is kind of a geodynamic assessment of the unknown extension of the WARS. Geological field mapping and dating of hydrovolcanic subglacial facies at volcanic structures in Ellsworth Land will provide the data base for (2) the quantification of past environmental changes).

What international collaboration is involved in this project?
A close cooperation is agreed upon with (1) the West Antarctic Ice Sheet Initiative (WAIS) research group through Slawek Tulaczyk, Dept. of Earth Sciences, Univ. of California Santa Cruz (UCSC), USA (IPY projects 35, 37 FASTDRILL), (2) Antarctic Neotectonics (ANTEC) Group through Reinhard Dietrich, Inst. fuer Planetare Geodaesie, Techn. Univ. Dresden, Germany, (3) John C. Behrendt and Wesley E. LeMasurier, INSTAAR, Univ. of Colorado, Boulder, Colorado, USA, (4) Rupert Sutherland, Inst. of Geological & Nuclear Sciences (GNS), Lower Hutt, New Zealand (IPY project 83; ANDRILL Principal Investigator, NZ Project 2: Tectonic evolution of the West Antarctic Rift System), (5) Philip T. Leat and Fausto Ferracioli, British Antarctic Survey, High Cross, Cambridge, UK.

FIELD ACTIVITY DETAILS

Geographical location(s) for the proposed field activities:
In order to test the model investigations are needed in Ellsworth Land, one of the least accessible and most poorly known areas in Antarctica. It stretches between Amundsen Sea, Ronne Ice Shelf and Bellingshausen Sea and encloses a triangle (see map) between Hudson Mts. at the Walgreen Coast, Sentinel Range in the Ellsworth Mountains and Eltanin Bay with the Rydberg Peninsula at the Bryan Coast.

Approximate timeframe(s) for proposed field activities:
Arctic: n/a
Antarctic: (02/05 – 04/05)      01/08 – 04/08      01/09 – 04/09

Significant facilities will be required for this project:
For logistic support are needed: (1) a research vessel like POLARSTERN for transport to and from the coast of West Antarctica at Amundsen and Bellingshausen Sea, as well as for a bathymetric survey in the Bellingshausen Sea; (2) multi-instrumented aircrafts for the aerogeophysical survey as operated by the Alfred Wegener Institut for Polar Research (AWI) in Bremerhaven, Germany, the Support Office for Aerogeophysical Research (SOAR) or the British Antarctic Survey, fuel depots needed; (3) helicopters to support ground based studies from field camps with structural, volcanological, geodaetic field studies as well as sampling campaigns for geochemical, dating and paleomagnetic analyses (snow terrain vehicles optional).

Will the project leave a legacy of infrastructure?
Yes, a system of GPS reference points (and possibly of seismic stations) as well as one or two Biwak huts.

How is it envisaged that the required logistic support will be secured?
Own national polar operator
Another national polar operator
National agency

Has the project been "endorsed" at a national or international level?
Applied for at the German IPY commission (meeting on January11)

PROJECT MANAGEMENT AND STRUCTURE

Is the project a short-term expansion (over the IPY 2007-2008 timeframe) of an existing plan, programme or initiative or is it a new autonomous proposal?
Yes

How will the project be organised and managed?
Self organized and managed by the university of Jena, Germany, in cooperation with the AWI and the BGR.

What are the initial plans of the project for addressing the education, outreach and communication issues outlined in the Framework document?
I will continue to give presentations on all levels in public and private schools as well as inform the press.

What are the initial plans of the project to address data management issues (as outlined in the Framework document?
Not yet considered.

How is it proposed to fund the project?
By funds of the German Science Foundation.

Is there additional information you wish to provide?
None

PROPOSER DETAILS

Professor Lothar Viereck-Goette
Institut fuer Geowissenschaften, Friedrich-Schiller-Universitaet
Burgweg 11
Jena
D-07749
Germany

Tel: +49 (0)3641 948720
Mobile: no
Fax: +49 (0)3641 948662
Email:

Other project members and their affiliation