Routine pollen analysis and macrobotanical analyses are reported for samples from CA ORA 116, an archaeological site overlooking San Joaquin Marsh, Orange County, California. Pollen preservation is good (deteriorated percentages 4 - 25%) and pollen concentration is high (3000 - 19000 grains cm-3). The pollen percentages are heavily dominated by weedy members of the sunflower family: Ambrosia and Liguliflorae. This dominance is in marked contrast to the pollen spectra in adjacent San Joaquin Marsh, which is dominated by the pollen of Chenopodiaceae-Amaranthus and "Other Compositae." Because Chenopodiaceae-Amaranthus and Other Compositae also dominate other sites near Newport Bay, the preeminence of Ambrosia and Liguliflorae at CA ORA 116, indicates very heavy disturbance of the vegetation of the site, itself. Pollen analysis of two artefact washes produced the same pollen spectra, indicating that the "background" pollen was more important that pollen from the materials processed with the artefacts. The macrobotanical samples contain the fruits and seeds of exotic plant species: Erodium cicutarium (filaree) and Medicago hispida (Abur clover) as well other disturbance indicators (weeds) such as Atriplex, Brassica nigra (black mustard), Chenopodium, Eremocarpus setigerus, Rumex, and Silene (Campion).
The presence of the introduced plants indicates that many samples contain admixtures of historic surface material. Silene is the most abundant macrofossil. Although infrequent, the presence of charred Sambucus (elderberry) in 8 samples may be securely attributed to human activity, and it is likely that Carex (sedge) and Scirpus (tule) in 4 samples were transported to the sites by humans. The complementary nature of the macrobotanical and pollen analyses can be seen in the abundance of Brassica nigra (mustard family) in the macrobotanical samples, the scarcity of mustard family pollen in the archaeological samples, but its abundance in the pollen samples from San Joaquin marsh. Likewise, the abundance of Ambrosia pollen in the CA ORA 116 samples contrasts with the scarcity of Ambrosia achenes in the plant macrofossil samples. The prominence of uplands plants producing the Chenopodiaceae-Amaranthus pollen type is also shown.BACK