POLLEN AND PHYTOLITH ANALYSIS OF PRE-MAZAMA AND POST-MAZAMA DEPOSITS AT FOUR SITES IN NEWBERRY CRATER, OREGON

Pollen and phytolith analysis of sediments from four sites in Newberry
Crater were examined to establish records of differences in vegetation between
the pre-Mazama (10,000-8,000 BP and 8,000-6700 BP) and the post-Mazama (3300-1300 BP) time periods represented. Sites 35DS220 and 35DS219 are presented by samples from the modern surface, as well as post-Mazama paleosols estimated to range in age from 3300 to 1300 BP. Site 35DS486 is represented by samples collected from post-Mazama deposits. Site 35DS34 exhibited both upper and lower pre-Mazama paleosols, as well as a possible house containing a hearth and an unrelated pit. These paleosols, as well as the house floor, hearth, and pit were also examined for pollen and phytoliths. Identification of differences in local vegetation between the pre-Mazama and post-Mazama deposits was sought.

本研究对纽贝里火山口（Newberry Crater）4处遗址的沉积物开展花粉与植硅体分析（Pollen and phytolith analysis），旨在建立所研究时段内马扎马火山喷发前（距今10000~8000 BP、8000~6700 BP）与马扎马火山喷发后（距今3300~1300 BP）两个时期的植被差异记录。遗址35DS220与35DS219的采样涵盖现代地表样本，以及年龄估算为3300~1300 BP的马扎马期后古土壤（paleosols）样本。遗址35DS486的样本取自马扎马期后沉积物。遗址35DS34则发育有上下两层马扎马期前古土壤，同时发现一处疑似带有灶坑（hearth）的房屋遗迹与一处无关联坑穴（pit）。本研究亦对上述古土壤、房屋地面、灶坑及坑穴开展了花粉与植硅体分析，旨在厘清马扎马期前与马扎马期后沉积物所对应的区域植被差异。