نتایج جستجو برای: sajama
تعداد نتایج: 26 فیلتر نتایج به سال:
This paper presents a high-resolution ice-core pollen record from the Sajama Ice Cap, Bolivia, that spans the last 400 yr. The pollen record corroborates the oxygen isotopic and ice accumulation records from the Quelccaya Ice Cap and supports the scenario that the Little Ice Age (LIA) consisted of two distinct phases—a wet period from AD 1500 to 1700, and a dry period from AD 1700 to 1880. Duri...
[1] An annually resolved pollen record spanning a 39-year period (1958–1996) from the Sajama Ice Cap, located on the western Bolivian Altiplano, reveals significant interannual variations in both pollen concentration and composition. The pollen assemblages within the annual layers are dominated by typical Altiplano taxa, especially Poaceae and Asteraceae. On an annual basis the pollen concentra...
[1] High-elevation ice caps develop an archive of atmospheric constituents and properties through the accumulation of snowfall. The timing of precipitation events, therefore, fundamentally governs the environmental information that ice core records can provide. These events are often highly seasonal, as are various postdepositional processes influencing the snow’s physical and chemical properti...
Quinoa (Chenepodium quinoa Willd.) is a grain-like crop which has a high potential of crop yield under arid environments. The objective of this study was to evaluate the responses of seed germination rate and percentage to temperatures and estimate cardinal temperatures in three quinoa cultivars (i.e., Sajama, Titicaca and Santamaria). Germination of quinoa seeds were daily counted at the tempe...
Nine sections from the Sajama ice core recovered from the summit of an extinct Andean volcano in Bolivia were analysed for various heavy metals to assess anthropogenic changes in the tropical upper troposphere over South America. These sam ples include two sections dating from 14, 100 to 19,200 years BP, corresponding to the Last Glacial Stage (LOS), one section dating from 2800 years BP (the l...
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