Scientists from the Technische Universität Dresden, Germany; NASA¹s Jet Propulsion Laboratory in Pasadena, Calif., USA; and the Centro de Estudios Científicos in Valdivia, Chile; made measurements of unusually high rates of crustal uplift within and adjacent to the Southern Patagonia Icefield in southernmost South America.

 Prof. Reinhard Dietrich from the Institute for Planetary Geodesy at the Technical University, Dresden, together  with Gino Casassa from Centro de Estudios Científicos, Chile and Erik Ivins from NASA JPL, discovered that the elevation changes of the mountains are a result of an acceleration in ice mass loss. The Southern Patagonian Icefield covers 13,000 square kilometers and is, after the ice sheet in Antarctica, the second largest ice mass in the Southern Hemisphere.

"Here two factors come together", describes Dietrich. "On the one hand, is the rapid ice mass loss of the Patagonian icefields.  These glaciers really began losing mass at the end of the Little Ice Age, about 120 years ago, and that loss has now reached an annual rate of about 30 cubic kilometers. Quite clearly, this accelerating loss of ice accompanies the regional climate warming over the last several decades. On the other hand, Earth's lithosphere and mantle  in southern Chile are capable of responding to changes in loads at Earth's surface at an anomalously rapid pace.  These fast mantle mass movements are caused by an unusually low viscosity of Earth's mantle there. "

The term "glacial isostasy" refers to the fact that the growth and collapse of large ice masses leads to lowering and raising of relative elevations of the underlying Earth's crust and mantle. An uplift rate of 39 millimeters per year,  determined in Patagonia by using GPS, is the largest glacial isostatic elevation change rate ever measured anywhere in the world to date, as the researchers report in the scientific journal "Earth and Planetary Science Letters".

Professor Dietrich states: "We will continue these investigations.  Our model calculations show that within some areas, even elevation rates of 50 millimeters per year are to be expected. This means, for example, that many of the mountain peaks of the Southern Andes that are well-known to the mountaineering community, such as Torres del Paine or Fitzroy, would each increase in elevation by a meter within about 20 to 30 years."

For additional information:
Prof. Reinhard Dietrich,
TU Dresden, Institut für Planetare Geodäsie,
Tel.: +49 351 463-34652,