Puna Region Research Articles

Soil catena variation along an alpine climatic transect, northern Peruvian Andes

Morphological and chemical properties of soils developed on end moraines of mostly quartzitic and granitic composition in the puna region of the northern Peruvian Andes vary with slope position and climate. Soil development was assessed on two catenas of similar age range (8–12 ka) in two different precipitation zones at summit, backslope, and footslope positions. Soil properties that show trends downslope and with increased rainfall are: greater clay content, greater organic-carbon content, and greater pedogenic Fe content. In addition, pH is lower in the higher rainfall area. Eolian material (mixed loess), forms the surface layer (A horizon) and may be responsible for the remarkable slope stability in the area. It is suggested that mixed loess provided material for chemical alteration and translocation of clay and Fe vertically and downslope in quartz-rich parent materials. Soil data suggest that the amount of climate change during the Holocene is limited; it is doubtful if the climate at the wetter end of the transect ever existed at the drier end.

Borates in the Argentine Puna: A New Application of Magnetic Separation

Large, highly marketable deposits of borate are situated in the north‐western Argentina. The exploitation of these deposits started in the beginning of this century. The exploitation and industrialization of some of these deposits during the 1980s turned the region into an important trading centre for export of raw borates and of boric acid. Technical specifications, as regards the iron content in those products, are very rigorous, particularly if they are used in manufacture of high‐quality glass. This paper presents a survey of the borate industry in the Puna region of Argentina. A purification technique for "hard borates", based on magnetic separation is described. The study has been carried out using pilot‐ plant magnetic separators at the IN BE MI, The Salta National University.

The lesser Rhea in the Argentine Puna region: present situation

The American ostriches Rhea americana and Pterocnemia pennata comprise an important item of the wildlife trade in Argentina. In addition to the trade in animal products, their eggs are also collected for food by local settlers. Very little is known about the distribution, densities, and ecology of these species. The present paper deals with habitat use, diet and population density of the subspecies P.p. garleppi which is located in the Andean region. between 3000 and 4000 m. These animals are entirely herbivorous and occupy open grasslands on the plains as well as rocky slopes and ravines with dense shrub cover. Studies reveal very low population densities which fluctuate considerably from year to year. Unless the present problems of human exploitation can be controlled, their prospects are very poor. Suggestions for their conservation and management are outlined.

Natural triploid hybrids between Solanum acauleBitter and S. infundibuliformePhilippi in the province of Jujuy, Argentina

The occurrence of natural triploid hybrids between tetraploid Solanum acauleBitter subsp. acaule and diploid S. infundibuliformePhilippi both tuber-bearing Solanums, in the Puna region of Jujuy, is reported. The natural hybrids, which are morphologically intermediate between their putative parents and completely male sterile, have a somatic chromosome number of 36. The artificial hybrids, obtained by crossing both parental species, closely resemble the natural ones thereby confirming their parentage. It is proposed to designate the natural hybrids Solanum x viirsooi hybr. nov.

Notes on the Puna Avifauna of Azángaro Province, Department of Puno, Southern Peru

Abstract In June 1975, we made the first dry (winter) season observations of puna birds in the Province of Azángaro, Department of Puno, southern Peru, adding nine species to the avifaunal list for the area. We observed no trochilids although they are known to be numerous during the wet (summer) season. Nesting of the Golden-spotted Ground-Dove (Metriopelia aymara) is described for the first time from Peru, and we report the breeding on the puna of two puna species that have been recorded on the coast in the dry season. We discuss altitudinal migration to the Pacific coast during the dry season, and include a species list for this puna region.

Structural belts and mineral deposits of northwestern Argentina

Three structural belts paralleling the north-northeast trend of the main Andes chain in northwest Argentina differ in age and character of igneous activity and in mineralization. In the gently folded ranges of the eastern belt, where Precambrian-Permian, Cretaceous, and Miocene-Recent formations are represented, there are no post-Cambrian granites, few basic intrusive or volcanic rocks, and only limited occurrences of metallic ores. The sedimentary section is less complete in the strongly folded and thrust-faulted cordilleras of the central belt; late granites (probably late Tertiary) are numerous, and associated vein and replacement deposits contain lead, zinc, silver, copper, and other metals. In the high block-faulted plateau of the western belt (the Puna region), iron and copper are associated with Precambrian granite masses, molybdenum, columbite-tantalite, and some bismuth with pegmatites of similar age, and gold, silver, antimony, tin, and lead with widespread Miocene-Quaternary volcanic rocks.