El Soldado is the largest (>200 Mt @ 1.4% Cu) of the known Cu manto-type deposits in central Chile. It is strata-bound within a submarine, bimodal calc-alkaline basalt - rhyodacite unit of the Lower Cretaceous Lo Prado Formation., which also contains marine carbonaceous shales and volcaniclastic sandstones. Although stratigraphically restricted, the clustered orebodies are mostly vein-like and discordant, controlled by a system of N-S to NNW faults fonned within a transtensional zone (cymoid loop) of a sinistral, strike-slip brittle shear system. Individual orebodies are zoned, with an external and deeper zone of barren pyrite, followed inward by concentric zones with chalcopyrite-pyrite, chalcopyrite bornite, bornite-chalcocite, and a central zone of chalcocite (± digenite ± covellite) and abundant hematite. The deposit was formed in two main phases: l)a low-temperature, diagenetic phase during which framboidal pyrite developed in association with migrated petroleum, at ca. 130 to 120 Ma; 2) a high-temperature (>300°C from fluid inclusions) hydrothennal phase at ca. 103 Ma, (coinciding with batholith emplacement), that deposited early hematite (± magnetite), followed by chalcopyrite, bornite and chalcocite, mostly replacing pre-existing pyrite, with the excess Fe forming hematite. Gangue minerals are calcite, albite, k-feldspar and chlorite. The hydrothermal Cu mineralization is associated with an increase in Na and depletion in K in host rocks, although there are localised zones of K increase in bornite-chalcocite assemblages near structures. Isotopic studies indicate that: a) the sulphur in diagenetic pyrite provided the bulk of the sulphur for Cu sulphides; b) petroleum was the source of carbon in bitumen and part of the carbonate; c) osmium in diagenetic pyrite was derived from the black shales; d) strontium in calcites was inherited from the Cretaceous arc lavas; e) oxygen isotopes in carbonates, and K-feldspar and atmospheric argon in K-feldspar plus the high salinity of fluid inclusions (21-26% NaCl equivalent) suggest a basinal connate-metamorphic brine was responsible for Cu transport, yet a (distal) magmatic component to the fluids cannot be ruled out.

The flight of the Mariner 2 spacecraft past Venus in December 1962 marked the start of a new era in the exploration of the solar system. At that time our knowledge of the terrestrial planets other than Earth (Mercury, Venus, and Mars) was largely astronomical in nature.

Every year millions of people visit Yosemite Valley, and they encounter stunning scenery that can overwhelm their senses. This experience is as true today as it was when the valley was discovered. The first recorded discovery of Yosemite Valley by western civilization was made by Major James D. Savage’s Mariposa Battalion, which, pursuing “hostile Indians” up the Merced River drainage, entered the valley on March 27, 1851. Early rumors about the valley had not prepared the men for the overpowering view now before them (Figure 1). <...>

GIS, the acronym for Geographic Information Systems, has been around since the 1980s. Although one can impute a number of characteristics from the use of this acronym, at the heart of the term “systems” lies a computer software package for storing, displaying, and analyzing spatial data. Consequently, the use of the term GIS implies an object or tool which one can use for exploring and analyzing data that are recorded for specific locations in geographical space (see Cowen [1988] for an early article articulating this type of definition and Foresman [1998] for a rich and varied account of the history of Geographic Information Systems).