Collaborative proposal: Tracing the Evolution of Late Quaternary Human Interaction and Mobility Patterns in Kenya

在国家科学基金会的支持下，伊利诺伊大学的Stanley Ambrose博士以及密苏里大学研究反应堆的Jeffrey Ferguson、Michael Glascock和David Robertson博士将研究现代人类行为发展的最后阶段发生的关键转变。互惠、合作和信息共享已被证明是在各种实验和自然环境中生存的一种有利战略。区域信息和材料交换网络是狩猎采集者在危险、不可预测的环境中生存的基础。什么样的考古证据可以表明人类社会采取了区域合作战略，这种转变是在何时何地发生的？长距离交换系统最持久、最丰富的证据是石器。黑玉岩是一种火山玻璃，在东非被广泛用于制作锋利的石器。每个火山源都有不同的化学成分。通过确定考古遗址黑铁矿文物的化学指纹，可以将它们与其来源联系起来，从而揭示有关交换和区域社会互动模式的信息。考古发掘的结果表明，大约在6万至7万年前，东非黑铁矿文物的出现频率大幅增加。这一变化与上一次冰河时代早期长期严重的环境退化相吻合。目前，非洲其他地区可能也发生了类似的变化，但尚不能通过对文物的化学分析来证实。由尼安德特人在欧亚大陆建造的当代遗址没有显示出来自遥远来源的石器原材料的类似增长。这一证据表明，合作战略首先是在非洲制定的，以应对剧烈的气候变化。遗传证据表明，东北非洲人在这种过渡之后走出了非洲，取代了欧亚大陆上古老的人类人口。他们的合作战略可能是他们在上一次冰河时代中期成功扩张的关键。安布罗斯博士和他的学生们的大部分工作将涉及对已知来源的黑铁矿进行采样，以及对肯尼亚更多露头的岩石进行调查。剩下的田野工作将包括从肯尼亚国家博物馆的藏品中挑选文物进行分析。密苏里大学研究反应堆(MURR)将使用X射线荧光和中子活化分析对数千件文物和来源样本的化学成分进行分析。这项研究将对社会和行为科学产生更广泛的影响，因为它将为气候变化在向现代人类行为过渡的最后阶段加强合作发展中的作用提供有价值的证据。它将促进对促进我们随后成功地从热带非洲扩展到世界其他地区以及尼安德特人灭绝的社会战略的理解。该项目还将影响该区域今后的研究，因为黑铁矿来源参考数据库将有助于以后的研究。最后，这项研究将为研究生提供野外地质学、考古学以及地球化学和核化学的实验室研究方法方面的科学培训和教育机会。

With the support of the National Science Foundation, Dr. Stanley Ambrose (University of Illinois) and Drs. Jeffrey Ferguson, Michael Glascock, and David Robertson (University of Missouri Research Reactor) will examine a critical transition that occurred during the final stages of the development of modern human behavior. Reciprocity, cooperation and sharing of information have been demonstrated to be an advantageous strategy for survival in a variety of experimental and natural settings. Regional information and materials exchange networks are fundamental for survival of hunter-gatherers in risky, unpredictable environments. What kinds of archaeological evidence can show that human societies adopt regional cooperative strategies, and when and where did this transition occur? The most durable and abundant class of evidence for long distance exchange systems is stone tools. Obsidian is a volcanic glass that was widely used for sharp-edged stone tools in East Africa. Each volcanic source has a distinct chemical composition. By determining the chemical fingerprint of obsidian artifacts from archaeological sites they can be linked to their sources, and thus can reveal information about exchange and regional social interaction patterns. Results from archaeological excavations show that a substantial increase in frequencies of obsidian artifacts occurred approximately 60,000 to 70,000 years ago in East Africa. This change coincides with a long period of severe environmental degradation during the early the last ice age. Similar changes may have occurred in other parts of Africa at this time, but cannot yet be validated by chemical analysis of artifacts. Contemporary sites in Eurasia made by neandertals do not show an analogous increase in stone tool raw materials from distant sources. This evidence suggests that cooperative strategies developed first in Africa, in response to dramatic climate change. Genetic evidence demonstrates that northeast Africans expanded out of Africa and replaced archaic human populations in Eurasia after this transition. Their cooperative strategy may have been the key to their successful expansion during the middle of the last ice age. The majority of the work by Dr. Ambrose and his students will involve sampling obsidian from known sources as well as survey for additional outcrops in Kenya. The remainder of the fieldwork will involve selecting artifacts for analysis from collections in the National Museums of Kenya. Analysis of the chemical composition of several thousand artifact and source samples will be carried out at the University of Missouri Research Reactor (MURR) using X-ray fluorescence and Neutron Activation analysis.This study will have broader impacts for social and behavioral sciences because it will provide valuable evidence for the role of climate change in the development of enhanced cooperation during the final stages of the transition to modern human behavior. It will promote understanding of the social strategies that facilitated our subsequent success in expanding from tropical Africa to the rest of the world, and the demise of neandertals. This project will also impact future research in the region because the obsidian source reference database will be useful for studying later periods. Finally, this research will provide scientific training and education opportunities for graduate students in field geology, archaeology and laboratory research methods on geochemistry and nuclear chemistry.