Projectile points across the Northern Rocky Mountain front: the Billy Big Spring Site (Blackfeet Reservation, Montana)

In the recent past, the Front Ranges of the Northern Rocky Mountains formed a permeable boundary that people repeatedly crossed for trade, subsistence, or warfare, and where people occupying different parts of western North America interacted. In this paper we apply a landscape approach to study pre-contact projectile point morphologies and raw materials, and related changes in the geographic affiliations of peoples using the Billy Big Spring Site, located near the Front Ranges in the Blackfeet Indian Reservation of Montana. This site contains numerous points recovered in chronostratigraphic contexts ranging in age from Late Paleoindian to Late Precontact. The sample includes types and raw materials alternatively typical of the Rockies/Plateau, the Front Ranges, and/or the Plains. Variation in the projectile point record at Billy Big Spring is consistent with the notion that, as observed in the recent past, information networks spanned a wide geographic area that englobed the Plains, the Front Ranges, and the Plateau/Rockies during most of the pre-contact period. Exceptions and changes in the geographic affiliations of people using the site can in turn be related to major environmental and demographic events that occurred in the region.

近代以来，北落基山脉前缘带（Front Ranges）曾是一道可渗透的边界，人群为开展贸易、维持生计或进行战争而反复穿越此处，分布于北美西部不同区域的人群亦在此进行互动交流。本研究采用景观考古学方法，对位于蒙大拿州布莱克菲尔德印第安保留地前缘带附近的比利大泉遗址（Billy Big Spring Site）所出土的接触前时期投射尖状器（projectile point）的形态、原材料，以及使用该遗址人群的地理归属相关变化展开研究。该遗址出土了大量投射尖状器，其出土的年代地层学背景年代跨度从古印第安晚期至接触前晚期。本次研究的样本涵盖了分别以落基山脉区、哥伦比亚高原区、前缘带以及大平原区为典型特征的投射尖状器类型与原材料。比利大泉遗址出土的投射尖状器记录所呈现的变异特征，与此前近代观察到的现象相符：在接触前时期的大部分阶段，信息交流网络覆盖了大平原、前缘带以及高原/落基山脉区这一广阔地理范围。而该遗址使用者的地理归属出现的例外情况与变化，则可与该区域发生的重大环境与人口事件建立关联。