| The Maya civilization peaked in terms of population density and socioeconomic complexity during a Classic Period extending from A.D. 250 to 900 only to end abruptly between A.D. 750 and 900. Climate change is included among the long list of factors that have been put forth to explain the Maya collapse. However, most efforts to reconstruct Mesoamerican climate conditions during the late Holocene have yielded equivocal results as there are few unambiguous sources of high-resolution proxy data for the region. Secondary mineral deposits within caves, known as speleothems, have been shown to be a rich source of proxy palaeoclimatic data. Until now, speleothem research has not been applied to humid, tropical regions.; This dissertation research concentrated upon a study area in western Belize, which is part of the Central Lowland region of the ancient Maya civilization. The study area possesses a humid, tropical climate characterized by warm temperatures and abundant, seasonal rainfall. The area is underlain by a thick sequence of Cretaceous age, carbonate rock which has given rise to a well-developed karst landscape. Although surface water supplies are practically nonexistent, archaeological evidence indicates that the area was densely populated by the ancient Maya. Today, the entire region is uninhabited.; An active stalagmite, approximately one meter in length, was collected from a cave within the study area in 1996. Variations in the stable isotope content of the speleothem, gray-level color analysis, and UV-stimulated luminescence analysis were used to construct the first high-resolution, proxy record of climate for the Central Lowland region. The record provides evidence that climatic conditions within the region have fluctuated considerably during the last 2,700 years. The data suggest that climatically drier conditions existed in the Central Lowlands during three known intervals of disruption in the ancient Maya civilization: Preclassic Abandonment, Maya Hiatus, and Classic Maya Collapse. The Late Classic Dry Phase, which began around A.D. 700 and extended to A.D. 1225, was the most prolonged dry period of the 2,700 year record. This dry period coincided with and thus, may have contributed to the collapse of the ancient Maya civilization. |
