POLLEN ANALYSIS OF SEDIMENT FROM HARPERS WELL, CALIFORNIA

The pollen record for Harper's Well in southeastern California is derived from samples
collected at 2 cm intervals to provide good resolution for identification of vegetation in sediments
thought to represent the historic era at the top of the column and prehistoric levels prior to
Spanish exploration and grazing at depths of 12 cm and below. Native Americans settled this
area between 1600 and 1774 AD. DeAnza's expedition in 1774 provides our first written
records. Prior to 1600 AD, Lake Cahuilla inundated the area. The final recession of the lake
is noted between 1540 and 1600. Pollen analysis was undertaken to provide a record of
vegetation between the recession of Lake Cahuilla and ranging operations.

加州东南部哈珀井的孢粉记录（pollen record）取自间隔2厘米采集的沉积物样品，以获取高分辨率数据，用于识别两类沉积物中的植被信息：一类对应沉积物柱顶部的历史时期，另一类为12厘米及以下深度、西班牙探险与放牧活动之前的史前地层沉积物。公元1600年至1774年间，美洲原住民在此区域定居。1774年德安扎探险队留下了该区域迄今最早的文字记录。公元1600年以前，卡胡利亚湖（Lake Cahuilla）曾淹没该区域，其最终湖退发生于公元1540年至1600年之间。本研究通过孢粉分析，重建了卡胡利亚湖退水至畜牧放牧活动开展期间的植被演化历史。