First Advisor

Kenneth M. Ames

Date of Publication


Document Type


Degree Name

Master of Arts (M.A.) in Anthropology






Projectile points -- Oregon -- Tualatin River Valley, Archaeological dating -- Oregon -- Tualatin River Valley



Physical Description

1 online resource (2, x, 122 p.)


Little is known about the time depth of human occupation in the Tualatin Valley. Archaeological investigations have produced no absolute dates for the few sites tested. Projectile points collected from the Ibach and Heynderickx farms in the Tualatin Valley show similarities to early point styles from sites in the Pacific Northwest dating from 6,000 to 10,000 years ago. To determine how old the Ibach and Heynderickx sites are, the undated collections of 107 Ibach points and 119 Heynderickx points are compared to two established chronological projectile point sequences, which had been constructed using the relative dating technique of frequency seriation. These sequences are further anchored with radiocarbon dates which extend back 6,000 years. On the basis of the comparison of Ibach and Heynderickx projectile point types to the seriated point types, it is suggested that the Tualatin Valley sites evidence occupation times at least as early as 6,000 years ago and possibly earlier.


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