Prado flood control basin. Davis, O.K., 1996.
Abstract
Tilia II ASCII file pradocor.txt



Davis, O.K. 1996.
Pollen analysis of a core from the Prado flood control basin.
Report Submitted to Donn R. Grenda, Statistical Research, Redlands, CA 92373. 16 p.

Routine pollen analysis is reported for 22 samples from a sediment core taken in the Prado Basin of western Riverside County, California. The pollen spectrum is dominated by high percentages (40-80 %) of sunflower (Other Compositae) pollen throughout the core. In the upper (81 - 320 cm), historic portion of the core, pollen preservation is good (10 - 25 % deteriorated) and the pollen concentration is low (1200 - 4300 grains cm-3). Filaree (Erodium) and Cruciferae pollen are relatively abundant, and sedge (Cyperaceae) pollen is abundant at 264 and 310 cm, marking a period of standing water in the basin at the beginning of the historic period. In the prehistoric portion of the core (320 - 1265 cm), pollen preservation is poor (30 - 65 % deteriorated) and the pollen concentration is very low (40 - 800 grains cm-3). Liguliflorae pollen (> 20%) and charcoal (> 10,000 %) are abundant. The bottom-most sample (1265 cm) contains little upland pollen, but has high percentages of willow (Salix) pollen, marking another period of standing water. The low pollen concentration in the core is apparently due to the rapid sedimentation (> 1.3 cm yr-1 in the historic period). The presence of well-preserved, but scarce pollen in the lower core (320 - 1265 cm) suggests that sedimentation rate also was very rapid. Erosion of soil surface material, including pollen, produced high pollen concentration in the historic period, but below 320 cm (ca. A.D. 1760) the pollen was diluted by rapid sedimentation of clastic material.

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