Quantifying the Duration and Impact of Human-Megafauna Overlap in Australia

在NSF考古计划的支持下，吉福德·米勒教授和澳大利亚的合作者将在澳大利亚西北部进行田野调查，以确定两种巨型鸟类--已灭绝的巨型鸟类Genyorennis和现存的澳大利亚麋鹿(Dromaius)--蛋壳碎片的人类背景。西澳大利亚州的野外活动提供了一个独特的机会，可以坚定地确定人类与已灭绝的巨型动物之间的相互作用，并量化人类与巨型动物重叠的持续时间。米勒的团队之前的田野调查记录了早期人类使用Genyoris鸡蛋作为食物来源，烹饪，以及后来在火中焚烧一些蛋壳。这是人类捕食澳大利亚巨型动物的第一个可靠证据。在早期人类活动遗址方面经验丰富的澳大利亚考古学家将陪同团队在烧焦的蛋壳和人类活动之间建立安全的关系。该项目的一个核心目标是应用四种独立的测年方法来确定人类和大型动物重叠的持续时间；美国和澳大利亚的测年专家团队已经组建了一个团队来实现这一目标。一项重大创新是开发了一种协议，以测量蛋壳中痕量铀同位素的水平，利用质谱学的最新发展，大大提高了检测水平。结合这些测量，蛋壳的矿物和有机成分中所含的氧、碳和氮的稳定同位素可以表征气候和鸟类的饮食状况。通过分析生活在人类殖民澳大利亚之前很久直到今天的鸟类的Dromaius蛋壳，将有可能独立地评估气候变化和可能发生的任何饮食变化。这样的数据集可以将与气候变化有关的影响与人类殖民造成的影响分开。比较灭绝的天才鸟和共存的卓迈厄斯的饮食策略将有助于理解为什么一种巨鸟灭绝，而另一种适应相同的压力并存活下来。澳大利亚的殖民是世界史前更大故事中的一个重要因素。更广泛地说，了解人类对从未被人类访问过的景观的殖民足迹，以及人类对陌生环境的适应性是至关重要的。这项研究有可能解决长期存在的争议，即人类是沿着海岸向澳大利亚南部扩散，然后再向内陆扩散，还是通过大陆内陆扩散。从创始人口开始的分散模式对适应和社会结构都构成了制约。人类早期历史上这些事件的断代一直受到缺乏可靠断代工具的阻碍。这项研究的一个关键方面是测试和完善禽蛋壳的U/Th测年。如果成功，这一强大的测年工具的加入不仅将重振澳大利亚早期人类遗址的研究，还将对非洲和欧亚大陆的考古研究产生深远影响。在非洲和欧亚大陆，鸵鸟蛋壳是许多考古遗址的常见元素，超出了14C测年的范围。这项研究激发了普通公众的想象力。米勒已经推动了相关的电视和大众媒体外联活动，并将继续这样做。

With support from NSF's Archaeology Program, Prof Gifford Miller and Australian collaborators will conduct fieldwork in NW Australia to define the human context surrounding eggshell fragments from two giant bird species, the extinct megafaunal bird Genyornis, and the extant Australian emu (Dromaius). The Western Australia field campaign offers a unique opportunity to firmly establish the interactions between humans and extinct giant animals, and to quantify the duration of human-megafauna overlap. Previous fieldwork by Miller's team documented early human use of Genyornis eggs as a food source, cooking, and later burning some of the eggshells in their fires. This is the first secure evidence of human predation on the Australian megafauna. Australian archaeologists experienced in early human occupation sites will accompany the team to derive secure relations between the burnt eggshell and human activity.A central goal of this project is to apply four independent dating methods to firmly define the duration of human-megafauna overlap; a team of US and Australian dating experts has been assembled to accomplish this goal. A major innovation is development of a protocol to measure trace levels of uranium isotopes in eggshells, capitalizing on recent developments in mass spectrometry that have greatly improved detection levels. In conjunction with these measurements, the stable isotopes of oxygen, carbon and nitrogen contained in the mineral and organic constituents of the eggshells allow characterization of the status of climate and the birds' diet. By analyzing Dromaius eggshells from birds living long before human colonization of Australia up through the present day it will be possible to evaluate independently changes in both climate and any dietary shifts that may have occurred. Such datasets allow the separation of impacts related to climate change from those due to human colonization. Comparing the dietary feeding strategies of the extinct Genyornis with co-existing Dromaius will help understand why one giant bird became extinct whereas the other adapted to the same stressors and remains extant.The colonization of Australia is an important element in the larger story of World prehistory. More generally, it is essential to understanding the footprint of human colonization of landscapes never before visited by humans, and the adaptability of humans to alien environments. This research has the potential to resolve long-standing disputes whether human dispersal was along the coasts to southern Australia and then inland, or through the continental interior. The dispersal pattern from a founding population provides constraints on both adaptation and social structures. Dating these events in early human history has been hampered by a lack of reliable dating tools. A key aspect of the proposed research is to test and refine U/Th dating of avian eggshell. If successful, the addition of this powerful dating tool will reinvigorate not only the study of early human sites in Australia, but it also will have profound effects in archaeological studies across Africa and Eurasia where ostrich eggshells are common elements of many archaeological sites beyond the range of 14C dating. This research captures the imagination of the general public. Miller has already facilitated related TV and popular media outreach activities, and will continue to do so.