Master of Science in Geoscience
First Committee Member
Matthew Lachniet, Chair
Second Committee Member
Third Committee Member
Fourth Committee Member
Number of Pages
Although the El Nino/Southern Oscillation (ENSO) is the most important source of inter-annual climate variability in the tropics, its Holocene history is poorly understood, particularly in Central America. A high resolution (-3.8 years/sample) paleoclimate record of Central American rainfall variability has been reconstructed from a U /Th-dated stalagmite (7890 to 6490 yrs B.P.) from Costa Rica to constrain the onset and variability of ENSO throughout the Holocene, and to determine its role in generating regional climate anomalies. I suggest drier conditions, forced by El Nino, are represented by higher 5180 values, and are correlative with higher 513C values, indicating that soil respiration rates are affected by regional climate variability, which are recorded in the speleothem stratigraphy gray-scale values. This study provides new evidence, based on 3 different proxies, that throughout the middle Holocene, rainfall was operating at interdecadal timescales, which I attribute to ENSO and the PDQ.
Costa Rica; Holocene Geologic Period; Paleoclimatology; Speleothems
Climate | Environmental Indicators and Impact Assessment | Geology
Azouz, April D., "Evidence of an Active ENSO and PDQ During the mid-Holocene from a Costa Rican Speleothem" (2006). UNLV Theses, Dissertations, Professional Papers, and Capstones. 1079.