Doctor of Philosophy (PhD)
Geography and Anthropology
This dissertation uses fossil (ice core) and modern pollen samples collected throughout the central Andes to investigate the paleovegetational changes in the area as well as the modern dispersal and depositional characteristics of pollen in this region of South America. The results of the fossil pollen study on Mt. Sajama reveal a vegetation history that closely corresponds to the chemical and physical records already published from the mountain. Pollen becomes abundant after 15,000 B.P. and suggests the occurrence of two distinct phases between 15,000 and 12,000 B.P. (a short interstadial and the Deglacial Climatic Reversal). After 12,000 B.P., there is a steady transition into the Holocene, which has been consistently warm and dry. However, for the accurate interpretation of the fossil pollen records, it is necessary to understand the dispersal and depositional characteristics of pollen on the ice caps themselves. Modern surface snow samples from two ice caps in the central Andes, the Quelccaya Ice Cap in Peru and Mt. Parinacota in Bolivia, have begun to answer some of these questions. In both cases, the prevailing winds play a major role in the dispersal of pollen onto the ice caps. The uniform pollen assemblages at Quelccaya suggest the majority of its pollen is deposited by “rainout” events originating from the local vegetation and areas farther to the east. Parinacota, on the other hand, seems to experience mechanical deposition from the prevailing winds as well as from local mountain winds. Inter-annual data from Quelccaya show the variability in these pollen assemblages and raise more questions as to the effect of the El Nino/Southern Oscillation cycle, sublimation, and the timing of the flowering season. Lastly, modern surface samples collected throughout the central Andes provide the first comprehensive understanding of the modern pollen-rain in the area, as well as the pollen provenance on central Andean ice caps. This data set is the first of its kind for the central Andes, and it serves to further the effectiveness of future fossil pollen studies in the central Andes by broadening our understanding of the modern relationships among pollen, vegetation, and climate in the region.
Document Availability at the Time of Submission
Release the entire work immediately for access worldwide.
Reese, Carl A., "Pollen dispersal and deposition in the high-central Andes, South America" (2003). LSU Doctoral Dissertations. 1690.