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? |
---|---|---|---|---|---|---|---|---|---|---|
327 | Beta-20956 | MicroSample | pollen | 4570 | 70 | 5156 | 5444 | 4879 | No | |
436 | Beta-20954 | MicroSample | pollen | 2440 | 80 | 2460 | 2722 | 2183 | No | |
437 | Beta-20955 | MicroSample | pollen | 3310 | 80 | 3488 | 3690 | 3335 | No | |
434 | Beta-20954 | MicroSample | phytolith | 2440 | 80 | 2460 | 2722 | 2183 | No | |
435 | Beta-20956 | MicroSample | phytolith | 4570 | 70 | 5156 | 5444 | 4879 | No |