Glaciar Dickson

Glaciar Dickson is located in Southern Patagonian Icefield (SPI) is within the Parque Nacional Torres del Paine. In 1897, the Dickson glacier had a great tongue that extended over 4.5 km southwards from Cerro Cubo. While eastward other tongue had joined with the front of the Frias glacier, draining into the lake Frias and then into Lake Argentino (Rivera & Casassa, 2004).

 

Since the "Little Ice Age", the glacier has experienced a retreat of 4.5 km until 2003, extending more Lago Dickson. From 2003 to 2015, the front south of the glacier has remained unchanged, partly because they were rocky outcrops on the glaciar front.

 

Since 1897 the glacier retreat (Table 1), its margins has made an outstanding Trim Line.

At the confluence of Glacier Dickson and Frias they began to appear in 1975 many lagoons of morainic materials and other forms of merger, denoting a setback and significant thinning.

 

Table 1: Recent changes Dickson Glacier 

YEAR VARIATION RESPECT PREVIOUS YEAR(m) RATE OF ANNUAL RETREAT (m/a) PHOTOS  SOURCES

 

  SOUTH FRONT NORTH FRONT SOUTH FRONT NORTH FRONT    
1897           Rivera & Casassa 2004
1944/45 -1570   34   TRIMETROGON Idem
1975 (March) -1214 0 40   Mark Hurd Idem
1984 (December) -1078   123   CH-60 Idem
1986 (January) 0   0   LANDSAT TM Aniya et al. 1997
1995 (May) -409   44   SAF 95 Rivera & Casassa 2004
1998 (November) -180 -2000 51 87 TERRENO DEL 7 DE NOVIEMBRE DE 1998 Idem 
2003 0 -1000 0 200 ASTER image Rivera et al, in press
2015 0 -1700 0 142 Landsat 8 image idem
TOTAL -4451 -4700  

 

 

In 1982 there was a great flood in Lake Dickson, rising 2 meters more than in a normal year.This flood would have occurred by the emptying of a proglacial lake, formed at the confluence of the Dickson and Frías glaciers (Peña & Escobar, 1983). This process has reoccurred on other occasions but not with the magnitude of 1982 .

In 1986 , the glacier had a total area of ??71 km², with a maximum length of 10 km, and a ratio of accumulation area versus total area (AAR) of 0.59 (Aniya et al., 1996). Between 1984 and 1986 , the southern front of the glacier no major changes, the northern front continued retreating , widening the lake dammed by the Frías and Dickson glaciers.

From 1986 to 1998 , the glacier continued to retreat on both fronts, the Dickson lake in November 1998 was roughly the same altimetry level as the glacial lake that formed at the confluence of the Dickson and Frías glaciers. Both lakes are joined and in 1999 Andrés Rivera and Heiner Lange crossed the Dickson Lake to the Frias Lake in a boat. During the 1999 campaign , it could be seen that from the Frías glacier and its proglacial lake, leaving a watercourse in the direction of Lake Dickson. The Frías glacier waters pour both the Atlantic Ocean and the Pacific.

 

dickson2.jpg (57075 bytes)

South front Glaciar Dickson. In back Cerro Stoke.

 

 

The Dickson glacier presents a sharp retreat during this century, it highlights the morphological changes from its confluence with the Frías glacier. The thinning is quite significant (-2.5 a -8 m/year). However in the last 5 years the glacier front Dickson has shown some stability , partly due to the appearance of rocks at the base of the front.

 

 

References

 

Aniya, M., Sato, H., Naruse, R., Skvarca, P. & Casassa, G. (1996): The Use of Satellite and Airborne Imagery to Inventory Outlet Glacier of the Southern Patagonia Icefield, South America. Photogrammetric Engineering and Remote Sensing, 62: 1361-1369.

 

Aniya, M., Sato, H., Naruse, R., Skvarca, P. & Casassa, G. (1997): Recent Variations in the Southern Patagonia Icefield, South America. Arctic and Alpine Research, 29: 1-12.

 

Peña, H. & Escobar, F. (1983): Análisis de las Crecidas del Río Paine, XII Región. Publicación Interna N° 83/7, Estudios Hidrológicos, Departamento Hidrología, DGA, 78 p.

 

Rivera, A., Acuña, C., Casassa, G. & Bown, F. (2002): "Use of remotely sensed and field data to estimate the contribution of Chilean glaciers to the sea-level rise." Annals of Glaciology, 34: 367-372.

 

Rivera, A. & Casassa, G. (2004): "Ice elevation, areal, and frontal changes of glaciers from National Park Torres del Paine, Southern Patagonia Icefiled." Artic, Antarctic and Alpine Research, 36(4), 379-389.