The Atacama Desert: Facts and Features
The Atacama Desert forms one of the major hyper-arid deserts of the world and it is known to be the driest place on Earth. The extreme aridity of the climate and unusual mineralogy of the regolith in the Atacama region is of considerable interest because of its value as an analogue to the Martian surface. The sedimentary succession in the Atacama Desert records deposition under an arid to semiarid climate from the late Jurassic (150Ma) to the present day (Hartley, 2005). Comparison with other long-lived deserts such as the Namib, Sahara and Australia deserts suggests that the Atacama is also the oldest extant desert. Arid environments account for 30% of the global land surface, a figure that is increasing annually owing to desertification (Hartley, 2002).
The present day location of the Atacama Desert within the dry subtropical climate belt is the principal cause of aridity (Fig. 1). This extreme aridity has resulted in a number of usual and unique features. These include the very low rates of erosion and accumulation of a range of unusual salts, including perchlorates, iodates, and nitrates in the soils as well as the more common halite, gypsum and anhydrite (Clarke, 2005). To understand the history of aridity in the Atacama Desert and its relevance to arid zone morphogenesis, regolith formation, and supergene mineralization, it is vital to approach this subject from a whole regolith perspective. Knowing about these approaches is critical for effective mineral exploration in the area because it hosts many of the world’s most significant porphyry copper-gold ore deposits (e.g. Chichicamata, the largest open pit copper mine in the world).
Sedimentology of the Atacama Desert
Miocene to Pliocene sedimentary rocks in northern Chile occur within two fault-bounded basins, the Central Depression (including an eastward extension, the Calama basin) and the Preandean Depression (Fig. 2) (Hartley and Chong, 2002).
The north-trending Central Depression extends
The present day location of the Atacama Desert within the dry subtropical climate belt is the principal cause of aridity (Fig. 1). This extreme aridity has resulted in a number of usual and unique features. These include the very low rates of erosion and accumulation of a range of unusual salts, including perchlorates, iodates, and nitrates in the soils as well as the more common halite, gypsum and anhydrite (Clarke, 2005). To understand the history of aridity in the Atacama Desert and its relevance to arid zone morphogenesis, regolith formation, and supergene mineralization, it is vital to approach this subject from a whole regolith perspective. Knowing about these approaches is critical for effective mineral exploration in the area because it hosts many of the world’s most significant porphyry copper-gold ore deposits (e.g. Chichicamata, the largest open pit copper mine in the world).
Sedimentology of the Atacama Desert
Miocene to Pliocene sedimentary rocks in northern Chile occur within two fault-bounded basins, the Central Depression (including an eastward extension, the Calama basin) and the Preandean Depression (Fig. 2) (Hartley and Chong, 2002).
The north-trending Central Depression extends