New and revised heat-flow density determinations for the Central Andes
in Chile and Bolivia between 60 degrees and 75 degrees W and between
15 degrees and 30 degrees S are presented. Heat flow was determined fr
om temperature logs obtained from fourteen boreholes in northern Chile
and from a large Bottom-Hole Temperature (BHT) data set in Bolivia. T
hermal data were corrected for perturbations resulting from drilling,
topography, and fluid circulation, and effects of porosity and tempera
ture were considered in adjusting thermal conductivity for in-situ con
ditions. Thus, the 74 reliable heat-how values available were used to
interpret heat flow in the context of lithospheric conditions. The hea
t flow in the Andean orogen shows a strong dependence on the different
tectono-morphologic units. Clusters of heat-how values projected onto
a W-E profile reflect significant changes from the Nazca Plate in the
west to the Chaco Basin in the east. Heat-flow density is low (20 mW/
m(2)) in the area of the Coastal Cordillera and high (50-180 mW/m(2))
in the active magmatic are and the Altiplano. The back-are region is c
haracterized by a comparably high heat how (80 mW/m(2)) whereas the An
dean foreland has a heat flow of 40 mW/m(2), which is slightly lower t
han the heat how in the adjacent Brazilian Shield farther east. The Ce
ntral Andean subduction zone shows a heat-flow pattern similar to the
active margin of the North American continent, but differs in the subd
uction parameters. Consequently, this results in different lithospheri
c thermal conditions. (C) 1998 Elsevier Science B.V. All rights reserv
ed.