HR: 0800h
AN: GC51C-1060    [Abstracts]
TI: Patterned Ground in Wetlands of the Maya Lowlands: Anthropogenic and Natural Causes
AU: * Beach, T
EM: beacht@georgetown.edu
AF: Georgetown University, Science Technology & Int'l. Affairs, SFS, 301 ICC, Washington, DC 20057 United States
AU: Beach, S L
EM: slbeach@gmu.edu
AF: George Mason University, Earth Systems & GeoInformation Sci., School of Computational Sciences, 5C3, Fairfax, VA 22030-4444 United States
AB: We use geological and archaeological evidence to understand the formation of patterned ground in perennial and seasonal wetlands in the karst depressions of Belize and Guatemala. Some scholars have argued that these features are the remnants of ancient Maya wetland fields, chinampas, on which intensive cultivation produced food that could begin to nourish the extremely high population of the Late Classic (A.D. 550-850). Others have argued that these were natural features or that they represent landscape manipulation for rising sea level in the Preclassic (1000 B.C. -A.D. 250). We present the evidence for ancient intensive agriculture and natural landscape formation with multiple proxies: excavated field and canal features, artifacts, pollen, soil stratigraphy, and water chemistry. Evidence thus far suggests that many regional depressions have Preclassic (1200 BC to AD 200) or earlier paleosols, buried from 1-2 m by eroded soils induced by Maya land use practices. These paleosols were buried by eroded sediments from uplands and by precipitation of gypsum from rising groundwater. The sedimentation occurred largely between the Preclassic and Late Classic, when ancient Maya farmers built canals in pre-existing low spots to reclaim these wetlands. Thus, stable natural processes, environmental change, and human manipulation have acted together to form patterned wetland ground over the later Holocene.
DE: 1803 Anthropogenic effects
DE: 1890 Wetlands
DE: 1600 GLOBAL CHANGE (New category)
DE: 1625 Geomorphology and weathering (1824, 1886)
SC: Global Climate Change [GC]
MN: 2004 AGU Fall Meeting