Geology/Earth Science Projects 2008

Reconstructing Holocene Climates in the Caribbean

Faculty Mentor - Dr. Patrick Mickler

This project studied tropical climate changes during the Holocene epoch by analyzing the stable isotopic composition of speleothems, secondary cements formed in caves, collected on Barbados, West Indies. Changes in the chemical and isotopic composition calcite in speleothems can be used as proxies for past climatic change. In this study we examined the ¹⁸O/¹⁶O ratio of CaCO₃ of the five speleothems which grew on Barbados between ~11,500 years before present to when they were recently collected. The oxygen isotopic record from the five Barbados speleothems were compared to pollen, ostracode charcoal from forest fire paleo-climate records collected from lake cores in the tropics and published in the scientific literature. Comparing and contrasting the climate records helps determine the timing and cause of climate shifts recorded in the Barbados speleothems.

Climate Change and Marsh Response of the Last 18,000 Years in Tulare Lake

Faculty Mentor - Dr. Peter Wigand

Regional climate change is reflected in variations of lake depth and marsh vegetation. We have utilized a Macrophysical Climatic Model (MCM), a model based upon the relationship between large-scale atmospheric dynamics and synoptic climatology to establish the main features of climate for the Tulare Lake area for the last 18,000 years B.P.. The paleobiotical record examined in this phase of the project compares the microfossils (pollen) from Tulare Lake core sediments and previous research done by Davis. Aquatic pollen will reflect the transitions between deep water marsh, shallow water marsh, and salt marsh. Terrestrial pollen will reflect the transition between cool, warm, wet, and dry climates.