Wilkins Jayne, Brown Kyle S, Oestmo Simen, Pereira Telmo, Ranhorn Kathryn L, Schoville Benjamin J, Marean Curtis W
Human Evolution Research Institute, Department of Archaeology, University of Cape Town, Rondebosch, Private Bag, South Africa.
Centre for Coastal Paleoscience, Nelson Mandela Metropolitan University, Port Elizabeth, Eastern Cape, South Africa.
PLoS One. 2017 Mar 29;12(3):e0174051. doi: 10.1371/journal.pone.0174051. eCollection 2017.
There are multiple hypotheses for human responses to glacial cycling in the Late Pleistocene, including changes in population size, interconnectedness, and mobility. Lithic technological analysis informs us of human responses to environmental change because lithic assemblage characteristics are a reflection of raw material transport, reduction, and discard behaviors that depend on hunter-gatherer social and economic decisions. Pinnacle Point Site 5-6 (PP5-6), Western Cape, South Africa is an ideal locality for examining the influence of glacial cycling on early modern human behaviors because it preserves a long sequence spanning marine isotope stages (MIS) 5, 4, and 3 and is associated with robust records of paleoenvironmental change. The analysis presented here addresses the question, what, if any, lithic assemblage traits at PP5-6 represent changing behavioral responses to the MIS 5-4-3 interglacial-glacial cycle? It statistically evaluates changes in 93 traits with no a priori assumptions about which traits may significantly associate with MIS. In contrast to other studies that claim that there is little relationship between broad-scale patterns of climate change and lithic technology, we identified the following characteristics that are associated with MIS 4: increased use of quartz, increased evidence for outcrop sources of quartzite and silcrete, increased evidence for earlier stages of reduction in silcrete, evidence for increased flaking efficiency in all raw material types, and changes in tool types and function for silcrete. Based on these results, we suggest that foragers responded to MIS 4 glacial environmental conditions at PP5-6 with increased population or group sizes, 'place provisioning', longer and/or more intense site occupations, and decreased residential mobility. Several other traits, including silcrete frequency, do not exhibit an association with MIS. Backed pieces, once they appear in the PP5-6 record during MIS 4, persist through MIS 3. Changing paleoenvironments explain some, but not all temporal technological variability at PP5-6.
关于晚更新世人类对冰川循环的反应存在多种假说，包括人口规模、相互联系和流动性的变化。石器技术分析能让我们了解人类对环境变化的反应，因为石器组合特征反映了原材料运输、加工和丢弃行为，而这些行为取决于狩猎采集者的社会和经济决策。南非西开普省的尖峰点遗址5 - 6（PP5 - 6）是研究冰川循环对早期现代人类行为影响的理想地点，因为它保存了跨越海洋同位素阶段（MIS）5、4和3的长序列，并且与丰富的古环境变化记录相关。此处呈现的分析解决了这样一个问题：PP5 - 6的石器组合特征（如果有的话）代表了对MIS 5 - 4 - 3间冰期 - 冰期循环怎样的行为反应变化？它对93个特征的变化进行了统计评估，且对哪些特征可能与MIS有显著关联没有先验假设。与其他声称气候变化的大规模模式与石器技术之间关系不大的研究不同，我们确定了以下与MIS 4相关的特征：石英使用增加、石英岩和硅质岩露头来源的证据增多、硅质岩加工早期阶段的证据增多、所有原材料类型的剥落效率提高的证据以及硅质岩工具类型和功能的变化。基于这些结果，我们认为觅食者在PP5 - 6对MIS 4冰川环境条件的反应是人口或群体规模增加、“地点供给”、更长时间和/或更密集的遗址占用以及居住流动性降低。其他几个特征，包括硅质岩频率，与MIS没有关联。背片一旦在MIS 4期间出现在PP5 - 6记录中，就会持续到MIS 3。不断变化的古环境解释了PP5 - 6部分而非全部的时间技术变异性。
