Playa Vista sediment cores, Los Angeles Co., California. Davis, O.K., 1998.
Abstract
Tilia II ASCII file plv8a.txt



Davis, O.K. 1998.
Pollen analysis of Playa Vista sediment cores, Los Angeles County,
California Report submitted to Statistical Research Tucson, Arizona. 20 p.

Routine pollen analysis is reported for 3 sites near Playa del Rey, Los Angeles County, California. Pollen analysis was performed for the Core 0, a 570 cm core taken with hand-operated piston corers near the lower levee of Ballona Creek; Core 1, a 1518 cm core near the barrier beach of Playa del Rey, obtained with a rotary auger using a 9-cm diameter split-spoon sampler; and Core 8, an 1829 cm core taken about 1 km inland from the beach using the same rotary auger. The pollen spectra of Core 1 and Core 0 are dominated by Chenopodiaceae-Amaranthus and Core 8 by "Other Compositae." The pollen concentration is extremely variable at all three sites (150 - 380,000 grains/cm3). The remains of marine organisms (dinoflagellates and foraminifera) are present in most samples, but are five times more frequent at the near-shore sites (Core 1 and Core 0) than in Core 8. Chronological control is provided by 7 radiocarbon dates for Core 8, with a date of 11,160 50 yr B.P. at 1506 cm.

Historic vegetation change is shown by increased percentages of Chenopodiaceae- Amaranthus pollen near the surface of Core 0. It likely results from the expansion of halophytic vegetation accompanying siltation of lower Ballona Lagoon during the historic period. The expansion of oak pollen in the surface sediments of Core 8 may result from urban landscaping. Prehistoric vegetation disturbance is evident in Cruciferae pollen percentages of Core 1 and Core 0 500 - 1500 yr B.P.

Pollen percentages and concentrations are highly variable throughout the late- and middle- Holocene, probably due to frequent flooding of Ballona Lagoon. From 6000 - 4000 yr B.P., Chenopodiaceae- Amaranthus percentages peak in Core 8 and Ruppia percentages peak in Core 1a, indicating maximum Holocene aridity.

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