GROUND WATER INTERACTIONS IN NATURAL AND ANCIENT MAYA WETLAND FORMATION AND USE

Ground water chemistry has played a critical role in the formation of perennial wetlands and the use of these wetlands by the ancient Maya over three millennia. Scholars have recognized the importance of rising water tables and gypsum precipitation in Maya field formation for two decades, but we are still fleshing out the role of water in the chronology, productivity, geography, and formation of these systems. We are using a new suite of paleoecological proxies for understanding soil geomorphology and ancient Maya interactions with wetlands across a broad environmental range in Belize. Multiple methods include carbon isotopic ratios, elemental analysis, pollen, phytoliths, macro-botanicals, artifacts, and soil and water chemistry. These wetlands lie in perennially moist coastal plain depressions and floodplains with water tables that vary seasonally from 2 m below the surface to above the surface. Over the last 2500 years, the wetlands have been aggraded by accelerated soil erosion, climatic change, flooding, field building, and a water table rise of water sources saturated with calcium and sulfate ions. This latter mechanism is a rarer geological process of environmental change that occurred after 2000 BP and during intensive Maya land use. Ancient Maya farmers responded to environmental change in both piece by piece and preplanned efforts to build 900-meter-long ditches to carve out new land for agricultural uses especially during the Classic Period (c. 1700-1100 BP). This correlates in time with intensive and widespread demographic and climatic changes. We compare these and new findings from wetland fields across a range of water conditions to understand the diversity of ancient Maya wetland interactions in the face of geomorphic change.