ACE Steering Group meeting, no. 2
2pm-6pm, Wednesday, 7th December 2005
Argent Hotel, Civic room
San Francisco
Proposals from Gary Wilson for marine seismic and permafrost sub-committees
Proposal to ACE for a marine seismic sub-committee
Rationale: Ross Sea Digital Geophysical and Geological maps (Antarctica) - ROSSMAP - is a proposed IPY project (IPY 154) that is focussed on developing a digital compilation of interpreted marine seismic reflection data for the Ross Sea. ROSSMAP will represent a substantial improvement on the previous compilation 1 and is motivated by new age control derived from drilling and new seismic data obtained in the last decade. These two facets lead to significantly new interpretations of the seismic stratigraphy of the region. The outcome of the proposed research will provide some of the important constraints on the ACE paleoclimate models for the region over the range of time periods of interest to ACE. Although ROSSMAP could stand alone as a proposed IPY project, it is suggested that IPY154 could form a cross-age-slice sub-committee of ACE, similar to the ACE radio-echo sounding sub-committee.
ROSSMAP has a particular regional focus, as strong scientific reasons exist for its proposed work program. From the ACE perspective the ROSSMAP project focuses on only part of their area of interest; however, it could form the basis of a more Antarctic wide project with the steering sub-committee membership appropriately modified as the scope of the project develops. Having the existing ROSSMAP project in place gives a good basis for this evolution and allows other sub-projects to be developed.
ROSSMAP: The aim of ROSSMAP is to produce a new series of digital seismic-stratigraphic and structural maps for the Ross Sea region. The proposal represents a major revision and important extension of the stratigraphic and isopach maps of the principal regional unconformities and seismic sequences in the Ross Sea made by the Ross Sea Regional Working Group of the Antarctic Offshore Acoustic Stratigraphy project (ANTOSTRAT) 1 . The research will consist of a re-interpretation of the extensive multichannel seismic data set recorded in the study area, taking advantage of more recent geological and geophysical data, and of further detailed information obtained from advanced reprocessing of chosen strategic seismic lines.
The great quantity of seismic data that has been acquired in the last 10 years will be incorporated in the new maps. Also, the new data acquired recently in the Eastern Basin over to western Marie Byrd Land will allow the coverage to be extended beyond the limit (165°W) of the original maps. Other features, such as seismic facies and the fault pattern available in regional maps 2,3 , will be integrated with the new data. The revision will also include the most recently available gravity, geomagnetic and drilling data 4 from the Ross Sea and the surrounding regions. In addition, detailed maps for some sub-areas will be produced to better define the detailed distribution, geometries and ages of the sediments. It is anticipated that ROSSMAP researchers will work with other ACE participants in developing an understanding of glacial processes as recorded by the seismic stratigraphy.
This study will provide an up to date synthesis of the tectonic and sedimentary history in the area. An accurate and detailed analysis of the seismic stratigraphy will improve understanding of the sedimentary and associated glacial and paleoclimatic processes around Antarctica and their implications for global climatic and environmental changes 5 . The research will form the basis for investigating the geology and geodynamic processes that occur in the Ross Sea and have affected the evolution of the West Antarctic Rift System. It will also provide the basis for current (ANDRILL) and future stratigraphic drilling initiatives.
The research involves four main components:
The proposal is an integration and extension to the whole of the Ross Sea of several existing projects, e.g. ANDRILL and VILMAP, and would thus incorporate the results of several groups presently working in different parts of the Ross Sea region. Significantly, digital maps can easily be updated on a regular basis, and the new Ross Sea digital maps will be maintained in a publicly accessible database that will contribute to key components of national strategic science plans.
The project will contribute to IPY Themes 1 and 2, by providing a record of environmental change in the Antarctic region during the Cenozoic climate fluctuations, since these changes are recorded in the stratigraphy. Moreover, this study will provide a unique opportunity for investigating links between the evolution of the east and west Antarctic sheets and the timing and magnitude of the main geodynamic processes and tectonic features of the West Antarctic Rift System. The project will also address the nature of the Gondwana-Pacific margin before continental break-up, which is a vital component in global plate reconstructions 6,7.
The project currently involves the following organisations:
Istituto Nazionale di Oceanografia e di Geofisica Sperimentale , Trieste, Italy
Università degli Studi “Roma Tre”, Roma, Italy
Ohio State University, USA
Institute for Crustal Studies, University of California Santa Barbara USA
University of Nebraska, USA
Institute of Geological and Nuclear Sciences, Wellington, New Zealand
Young researchers will be involved through Masters and Doctoral projects supported by national funding agencies. Public access to the project results will be promoted by:
Training courses for undergraduates in collaboration with National Antarctic Museums.
An ACE sub-committee: An ACE-MARINE SEISMIC subcommittee could act to encourage the integration and acquisition of marine multichannel seismic data in Antarctica, and develop a common seismic stratigraphy and interpretational models for sedimentation on the Antarctic margin. The outcome of this sub-group will be to provide the best seismic coverage and understanding of sedimentary cover and processes on the Antarctic embayments for the ACE community. The action plan, to be developed during 2005-6, includes the following:
Provisional Committee:
Chiara Sauli (Italy); Terry Wilson (USA); Bruce Luyendyk (USA); Stuart Henrys (New Zealand); Francesco Salvini (Italy); Nigel Wardell (Italy); Christopher Fielding (USA)
Wilson proposal for permafrost sub-committee
Proposed ACE Initiative: Neogene Soils, Sediments, and Buried Ice in the Dry Valleys
Climate data from glacial sediments, lake sediments, ground and buried ice, soils, permafrost and periglacial features in the Dry Valleys have been sparse. To improve our understanding of the Antarctic climate system, it is crucial to understand climatic signatures that may be present in these features. Although these features probably may not yield high resolution climate data, their data provide an terrestrial history that will complement marine and ice core data.
Priorities
-Understand the evolution of Neogene ice and sediments in the Dry Valley area and how they relate to the extent and timing of ice sheets
-Interpret climate history recorded in soils and permafrost
-Interpret periglacial features as indicators of past and current climate change
-Evaluate environmental changes as recorded in lake sediments
Objectives
-How are past atmospheric conditions recorded in soil chemical parameters including salts and ground ice isotopes ?
-What is the biological signature in deep cores and how is this related to climate?
-How can the stratigraphy of Neogene sediments be used to understand past environments in the Dry Valley?
Work Plan
-Establish a system of shallow (< 20 m) boreholes starting in the Dry Valley region for characterizing permafrost conditions (thickness, temperature, composition) and observing the thickness and characterization of glacial sediments.
-Down hole geophysical measurements (temperature, resistivity, density) to characterize sub surface features, ice content, biological activity.
-The use of geophysical (GPR and resistivity) surveys coordinated with cores to enhance remote sensing of subsurface features in the Dry Valleys.
-Facilitate the establishment and maintenance of weather stations at sites representing a gradient of conditions.
Sub Committee Members
Sletten (US)
Dickinson (NZ)
Gilichinsky (Russia)
Trombo (Argentina)
We can also suggest people from Italy, UK, Switzerland, Norway, Spain, South Africa, Canada….as needed
Another aim of this initiative would be to bring together people on terrestrial problems relating to Antarctic Climate Evolution who have never been in a coherent group. the main players we can think of are:
1) Denton, Sugdon, Marchant, Hall group and those that work with these people...This is by far the largest group; they have a good track record and are well funded.
2) U Washington group: Sletten, Hallet, Puketonen (periglacial and chemistry)
3) David G and the russian drillers; Chris Mckay (astrobiology); Warren Dickinson (buried ice, permafrost chemistry)
4) Barry Lyons- LTER group and modern processes and present environment
5) Peter Doran (lake sediments)
6) Several Italians working in North Victoria Land
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