Lake Ayauch(i)


Bush and colleagues (1989:303) extracted sediment core samples from the bottom of Lake Ayauch(i), 20 m beneath the lake surface. The longest sediment core was 3.26 m long and represents more than 7,000 years of accumulated deposits. In ancient times people living in the vicinity of the lake must have grown maize nearby because maize pollen and phytoliths made their way into the lake sediments, beginning as early as 6000 years (cal BP) ago. The authors note that by ca. 2500 years ago there was a dramatic increase in the frequency of maize phytoliths, suggesting that agriculture intensified beginning around that time (Bush et al. 1989:304).

ID Other ID Type Subtype Uncal BP (years) ± 1 σ (years) Median cal BP (years) Lower cal BP (years) Upper cal BP (years) δ13C Contaminated?
Beta-20956 MicroSample pollen 4570 70 5156 5444 4879 No
Beta-20954 MicroSample pollen 2440 80 2460 2722 2183 No
Beta-20955 MicroSample pollen 3310 80 3488 3690 3335 No
Beta-20954 MicroSample phytolith 2440 80 2460 2722 2183 No
Beta-20956 MicroSample phytolith 4570 70 5156 5444 4879 No

Attached Files

Sediment stratigraphy showing maize phytoliths and pollen present at Lake Ayauch(i), Ecuador. 'N' marks where Zea phytoliths were searched for but not found. The radiocarbon date in this figure correspond to the following lab sample numbers from top to bottom: Beta 20954, 20955, 20956, and I-13,306) (Bush et al. 1989:304; Figure 1). Imagen de la estratigrafía del Lago Ayauchi en Ecuador donde se recuperaron fitolitos y polen de maíz. La letra 'N' en el diagrama muestra la ausencia de fitolitos de maíz. Los números de laboratorio comienzan desde arriba con Beta-20954 hasta Beta-20956 y al último I-13,306 con la fecha más antigua de la sequencia (Figura 1 en Bush et al. 1989:304).

References Cited

Bush, M. B. and P. A. Colinvaux
    1988    A 7000-Year Pollen Record from the Amazon Lowlands, Ecuador. Plant Ecology 76(3):141-154.

Bush, M. B., D. R. Piperno and P. A. Colinvaux
    1989    A 6,000 year history of Amazonian Maize Cultivation. Nature 340:303-305.