INTERPRETATION OF THE PALI-AIKE AREA, A SOUTHERNMOST
PATAGONIA QUATERNARY VOLCANIC FIELD
Hugo Corbella
Julio Jacobo Berlles
Domingo A. Gagliardini
CAERCEM-CONICET
Satellite Radiometry Division
Julián Alvarez 1218
Buenos Aires. 1414, Argentina
ISPRS Commission VIT / Working Group 2
ABSTRACT
A commission of CONICET (Argentine National Council for Scientific and Technical Research) has been
studying the Pali-Aike volcanic field, the southmost quatemary magmatic event of the extradean Patagonia,
since 1989. The geological cartography of the area from field survey and sampling, the seismic, gravimetric
and magnetometric characteristics of the different volcanic and hypabyssal magmatic bodies, and the
petrographic, geochemical and geochronological studies of the outcropping rocks have or are going to be
published in several preliminary papers.
The cartography of the area was initially done from conventional acrial photographs and Landsat images. For
the areas where photographic coverage was not available, new zenithal 35mm panchromatic and IR images
were obtained. ERS-1 SAR images are also being used from 1992, making it possible to compare this
information with the one previously mentioned.
From this comparison, it can be realized that in desertic areas of low relief, the ERS-1 images give a better
representation of the topography and, have a higher capacity to enhance subtle differences in relatively flat
terrains and so it is easier to detect and individualize low relief landscapes such as:
a) Low relief drainage patterns.
b) Different levels of river terraces, specially in areas where the variation of the river vertical profile
(alternation of head-waters level and sea level) by the successive glacial and interglacial periods produced
multiple alluvial adjustments.
¢) Phrecatomatic structures and their hyaloclastic sedimentary ring. Specially in those maars partially
obliterated by colic or fluvial erosion.
d) Broad magmatic domes, sometimes associated with hypabyssal bodies.
¢) Linear structural features detected by radar and not detected by previous surveys.
Therefore, it is possible to conclude that ERS-1 SAR images have proven to be very useful as a complement
in the geological and volcanological study of the Pali-Aike area.
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