STRATIGRAPHIC POLLEN ANALYSIS OF SEDIMENTS FROM BARTON GULCH (24MA171) , SOUTHWESTERN MONTANA

Stratigraphic pollen samples recovered from a 5.85 m deep section located in a recent placer mine cut along the north margin of the Barton Gulch Valley were examined to identify elements of the local vegetation and to reconstruct paleoenvironmental conditions from 10,360 BP to 3,900 BP. The Barton Gulch area was occupied by Paleoindians by 9,400 BP, and occupational strata are noted through approximately 3,900 BP (Davis et al. 1988, 1989; Davis 1993). Chronostratigraphic markers include stratum 12, represented by Mazama ash (6,850 BP) near the center of the column, the radiocarbon age of 10,360 BP at the base, and an end date of approximately 4,000 BP 20-30 cm below modern fan surface.

本次研究对采自巴顿谷（Barton Gulch Valley）北缘新近开挖的砂矿采掘剖面（深度5.85米）中的地层花粉样品开展分析，旨在鉴定当地植被组成，并重建10360 BP至3900 BP时段的古环境状况。巴顿谷地区在9400 BP时已有古印第安人（Paleoindians）活动，且人类活动地层的沉积年代可追溯至约3900 BP（Davis等，1988、1989；Davis，1993）。该剖面的年代地层标志包括：剖面柱中部附近以马扎马火山灰（Mazama ash，6850 BP）为代表的第12层、底部的放射性碳测年年龄（10360 BP），以及现代扇面地表下20~30厘米处的近似终止年代（约4000 BP）。