Flotation versus dry sieving archaeobotanical remains: A case history from the Middle Horizon southern coast of Peru

During excavations at the site of Casa Vieja located in the Peruvian coastal desert, archaeological plant remains were systematically collected to assess whether it is more productive and informative to sieve sandy sediments in dry environments or to process such samples by water flotation, a persistent methodological concern. At Casa Vieja, dual subsamples were collected and analyzed using both of these procedures. For dry, sandy sediment conditions, each processing strategy was found to yield a different view of the botanical remains. Dry sieving recovers more of the larger plant specimens whereas water flotation yields more of the smaller-sized material. These results should be incorporated into archaeological research designs in the future, especially for desert environments.