An analysis of microparticle size distributions and relationships with slope and particle coarseness factors

• Main Author: Gross, Steven M.
• Other Authors: Thompson, Lonnie G.
• Format: Thesis
• Language: English
• Published: The Ohio State University 1987
• Subjects: Ice cap; ice core
• Online Access: http://hdl.handle.net/1811/75866

The major focus of this study is to investigate the relationships between the distribution of microparticle size with seasonal fluctuations over short and long term periods in the southern Andes of Peru, as well as to determine if a change in slope and coarseness factors can be associated with the last major change in climate "The Little Ice Age." Microparticle size distribution data, slope and coarseness factors were calculated from microparticle concentration data obtained from ice core samples taken from the summit dome of the Quelccaya Ice Cap, located along the easternmost edge of the Peruvian Andes. From this study it was concluded that significant changes occur in slope values and coarseness factors associated with the last major climatic change "The Little Ice Age." The size distribution of microparticles indicated by slope values suggests a higher percentage of large particles relative to small particles were deposited during the Little Ice Age. This is most likely due to greater wind speeds during the Little Ice Age period. A direct relationship is established between decadal microparticle size distributions and calculated slope values. Generally, higher negative slope values indicated a steepening of the microparticle size distribution, related to a higher percentage of small particles being deposited. This seasonal fluctuation (wet and dry) in microparticle size distributions can be attributed to seasonal changes in regional circulation, precipitation, and atmospheric radiation levels effecting mass loss. No embargo