I. Background

During the year 2003, Chile, in a mark of agreement and collaboration with different national military and scientific organizations, made a preliminary evaluation to implement a scientific expedition in Antarctica. The project, named the "Scientific Expedition to the South Pole" was planned and executed in the 2004/2005 summer season.

Once the financial and organizational responsibilities and the plans and expected results were put together, the corresponding documents were prepared and presented to the National Commission of Evaluation of Antarctic Environmental Impact (CONAEIA), and to the Chilean Antarctic Institute (INACH), and coordinated with the United States Antarctic Program (USAP) for support at the Amundsen-Scott Base. Similarly, to activate the Polar Station "Parodi" in the Patriot Hills, the support of the British Antarctic Survey of the United Kingdom was obtained. Through them, support was provided at Rothera Base which permitted the operation of the Twin Otter aircraft that went to that sector for the activation of the station and for the support of search and rescue (SAR).

II. Expedition Objectives

A) General Objectives:

To carry out a scientific expedition in the Antarctic continent, from the Patriot Hills to the South Pole during the Antarctic summer 2004/2005, with the help of different government organizations, to increase the national presence in the Antarctic territory through scientific, operational and logistical activities.

B) Scientific Objectives:

1) To make glacial and geophysical investigations in a transect of the Patriot Hills to the South Pole, to study the

accumulation of snow in the last 200 years, the change in climate, atmospheric chemistry, actual meteorological conditions, geophysical and geodesic characteristics of the transition between western and eastern Antarctica.

2) To carry out rises and cartographic profiles of the area.
3) Establishment of a national geodesic network up to the South Pole.
4) Observations of earth's gravity along the transect.
5) Remediation of control points in the Patriot Hills.
6) Technical development of geophysical sensors on board the ground vehicles.
7) Development of Chile's logistical capacity to make long distance traverses into the interior of the continent.

III. Development of the Expedition

The expedition received a sendoff from Punta Arenas by the president of the Republic; the following significant activities took place between October 2004 and January 2005:

1) Aerial transport to Antarctica (31 tons of personnel, equipment and vehicles) was made by the Armed Forces of Chile to the Parodi Polar Station in the Patriot Hills with two Hercules C-130 and one Ilyushin Il-76 aircraft from the company Antarctic Logistics and Expeditions (ALE).

2) At the Patriot Hills, the base camp was organized by the Armed Forces of Chile at Parodi Polar Station, with its interconnected modules and systems.

3) Departure from the Patriot Hills to the South Pole: The expedition began the motorized journey in the Patriot Hills from 80°18'S-81°23'W on 13 November 2004, with the mission of reaching the geographic South Pole after a motorized journey estimated at 1084 km, meanwhile making an examination of the route to develop a scientific work program for the return trip.

4) At the South Pole:

The expedition stayed 8 days at the South Pole, time dedicated to vehicle maintenance for the return trip, preparing the scientific equipment for the execution of the scientific plan, protocolic activities, familiarization with the American base, and refueling.

They made a presentation of the operative plan of the expedition and completed scientific activities to the scientists at the Amundsen-Scott base, administered by the National Science Foundation.

5) Return trip to the Patriot Hills:

The expedition began the trip on the 9th of December 2004, traveling a route in which to complete the principal activities of the scientific plan that was considered fundamental to the work of ice sampling and extending the national geodesic network.

The traverse was carried out without problems according to the program, reaching the Patriot Hills on 31 December 2004 after 23 days on the journey.

6) Redeployment of personnel and equipment:

On the 1st of January 2005 they began the planned work of vehicle maintenance for the end of the trip. The vehicles were placed in a pit, stored on a piece of wood and wrapped in a PVC cover. The modules were left out in the open.

On the 10th of January of 2005 the expedition was transported to Punta Arenas by air.

IV. Scientific activities developed by the Military Geographic Institute (IGM) and the Center for Scientific Studies (CECS) at Valdivia:

1) Gravimetric measurements:

Each 10 km of advance along the journey gravimetric measurements were taken to determine the geodial undulation between the Patriot hills and the South Pole, using a Lacoste-Romberg gravity meter. The measurements obtained will be transformed into units of gravimetrical readings by the IGM, to be sent to international agencies: the National Imagery and Mapping Agency (NIMA) of the USA, and to the Brazilian Institute of Geography and Statstics (IBGE). The data is to be consistent with the EGM96 geopotential model of the Earth.

2) Geodesic measurements:

Statistical measurements were taken each 20 km to determine position and altitude of the 53 established geodesic markers that were measured on the way as well as on the return trip, with the aim of measuring the actual points and from that to determine the displacement of the ice flow. This work was done to support CECS and the scientific work relating to climate change.

3) Establishment of a new geodesic point:

During the return trip a new geodesic point on the Lewis nunatak in the Theil Mountains, designated MT-001, was established, making it the southernmost geodesic point on the continent--contributing to the extension of the national geodesic network. This will permit more accurate geodesic surveying of this area, and will serve as a standard for future measurements.

4) Extracting ice samples:

In relation to the world wide climate change, and if this event is caused naturally or by man, it has been discovered that the large masses of ice are the best natural record of climatic history, and from ice samples valuable information of past atmospheric composition can be extracted. During the traverse ice samples were extracted to 50 meters, which will permit the evaluation of climate oscillations, historic composition and global pollution in the last three centuries.

5) Surface snow samples:

During the traverse, surface snow samples were obtained every 10 km to determine their actual composition and to compare them with the ice samples that were taken. Every 20 km snow measurements were taken with a Mt. Rose snow core sampler to determine the snow density and to evaluate the density variations between the Patriot Hills and the South Pole.

6) Ice thickness:

Radar was used to take measurements to evaluate the dynamics and flow of the ice to determine and map the subglacial morphology along the traverse. At 87 degrees latitude, ice thickness was found to be 3,200 meters.

7) Ice accumulations:

Measurements were made using ground-penetrating radar (GPR) with the objective of measuring the internal layering of the surface snowfall in the first 80 meters, to support the ice sampling work.

8) Technical development of radar to detect cracks:

Radar was used to measure snow accumulations--work that validated the basis of prior calculations of the velocity and balance of the ice masses.

Theil Mountains:

The Theil Mountains were encountered 460 km to the south of the Patriot Hills. Here the IGM had to qualify a new geodesic point with the aim of increasing the geodesic network. An integral group of military and scientific personnel were put together and included in the vehicle convoy; they ventured 60 km into the interior of this mountain range.

The establishment of this new geodesic point took place at the Lewis Nunatak (85°41'S-88°01'W). Due to the presence of cracks, access to this place had to be made on foot for the last 3 km so as not to endanger the vehicles.

This point is the southernmost nunatak and the last exposed ground of the National Antarctic Territory. From here to the South Pole extends the Polar Plateau--an extensive 500-km plain of ice. This motivated the ascent of this nunatak, which is 1949 meters above sea level.

V. Scientific application and evaluation phase:

Starting from January 2005, work processes are being developed for the analysis of the data and the evaluation of the scientific findings of the expedition. The results will later be published in scientific journals.

VI. Conclusions:

1) With regards to the fulfillment of the plan and its objectives, Chile has demonstrated its operational and logistic capacity to plan, coordinate and implement a long distance traverse into the interior of the Antarctic continent, in a safe and efficient manner contributing to the knowledge of the national territory, by means of an active penetration in the direction of the South Pole.

2) This scientific expedition demonstrates to the world-wide scientific community Chile's vision in this context, by executing definite activities, the engagement of science that contributes to the international community, with significant contributions to the investigation of global climate change, something of present concern to the world-wide community.

3) Consistent with the earlier offer, the tracked vehicle "Berko TL6" along with its three modules with the capacity for 10 crew members and 2 drivers, was used in the Patriot Hills zone, with a scientific activities support unit of the countries and/or international organizations that helped share and finance the efforts.

4) If there is no interest from the international scientific community, eventually and analyzing it case by case, the vehicles will also be offered to tourist operations as a service unit, to serve as transport for their travels, due to its actual location in the Patriot Hills, whenever they arrange to finance the usage costs.

VII. Acknowledgements:

The Chilean Air Force gives public acknowledgement to the British Antarctic Survey, for the support given at Rothera Base, which served as a launching point for the activation stage of the Polar Station "Lieutenant Parodi" in the Patriot Hills. This permitted the operation of the two Twin Otter aircraft, providing the capability for search and rescue during the mechanized travel to the South Pole.