Development of a Stable Isotope Technique for Sourcing Olivella Shell Beads in California

贝壳珠是美国加州原住民的一种货币。在该州的一些地方，珠子可以用来购买商品，通过购买进入精英社会团体，或者从其他个人那里获得劳务等服务。贝珠货币也促进了史前贸易。土著人民建立了广泛的贸易网络，以运输黑铁矿、篮子、食物、盐和其他货物。由于未知的原因，一种小型海洋蜗牛Olila biplicata的壳-紫色橄榄-被选为这一身份。奥利维拉珠子来自太平洋海岸，远在东部的犹他州、科罗拉多州和爱达荷州都能找到。其中大量的珠子是在南加州的圣巴巴拉地区制造的，那里以广泛的珠子生产中心而闻名。这些中心的突出地位导致一些考古学家提出，尽管在加利福尼亚州和俄勒冈州海岸发现了大量的奥列夫拉，但圣巴巴拉的薄荷糖制造了大部分珠子。杰尔默·埃肯斯和霍华德·斯佩罗将开发一种方法，使用氧和碳同位素来识别贝壳珠子的来源。根据在圣巴巴拉、蒙特利湾、博德加湾和南俄勒冈州收集的现代贝壳的初步数据，他们表明，由于海水温度和上升流的差异，生长在沿海某些地区的贝壳具有明显的同位素特征。利用目前的资金，他们将扩大这项研究的地理广度，并包括古代贝壳，以确定他们的指纹识别方法可以扩展到多远以前。这项基础研究最终将使考古学家能够解决几个有趣和相关的问题，其中一些问题将作为当前研究的一部分进行讨论。事实上，是不是圣巴巴拉的居民生产了全州所有的钱珠？如果是这样的话，他们是在整个史前时期一直控制着这种珠子的生产，还是只在某个特定的时间点出现了一种“集中式造币厂”？如果不是，贝壳珠还在哪里生产？最后，这项研究还将提供有关过去海表面温度和上升流变化的宝贵的古气候数据。今天的情况与过去相似吗？如果不是，它们在几千年里发生了怎样的变化？我们能否将其他古环境数据(例如，渔业产量、植被、降雪量等)与古代海面温度和上升流联系起来，以便我们能够更好地理解和预测其中一项的变化对另一项的影响？研究人员计划将这些发现纳入加州大学戴维斯分校人类学博物馆学童的教学模块中，每年有500多名K-12学童参观该博物馆。孩子们学习接触前的美洲原住民的生活方式，以及考古学家如何从材料遗迹中重建过去。本单元将展示如何使用听起来像是技术的分析技术(即质谱学)来回答听起来简单的问题(即，谁与谁交易)。这种外展通过提供与考古学家和真实文物的互动和动手体验，使过去变得生动起来。

Shell beads comprised a type of currency for Native American Californians. In parts of the state, beads could be used to purchase goods, to buy one's way into elite social groups, or to acquire services such as labor from other individuals. Shell bead currency also facilitated prehistoric commerce. Native peoples established extensive trade networks to move obsidian, baskets, food, salt, and other goods. For unknown reasons, the shell of a certain small-bodied marine snail, Olivella biplicata - the purple olive, was chosen to serve in this capacity. Derived from the Pacific Coast, Olivella beads are found as far east as Utah, Colorado, and Idaho. A large number of these beads were made in Southern California in the Santa Barbara area where extensive bead production centers are well known. The prominence of these centers has led some archaeologists to propose that Santa Barbara "mints" were responsible for the production of most if not all beads, despite the fact that Olivella is found in abundance all along the California and Oregon coast.Jelmer Eerkens and Howard Spero will develop a method to fingerprint the source of shell beads using oxygen and carbon isotopes. Based on preliminary data from modern shells collected in Santa Barbara, Monterey Bay, Bodega Bay, and Southern Oregon, they have shown that shells growing in certain regions along the coast have distinctive isotopic signatures due to differences in seawater temperature and upwelling. With the current funding they will expand the geographic breadth of that study and include ancient shells to determine how far back in time their fingerprinting method can be extended. This basic research will ultimately allow archaeologists to address several interesting and related questions, some of which will be touched upon as part of the current research. Were, in fact, Santa Barbara inhabitants responsible for the production of all money beads found throughout the state? If so, did they maintain control over the production of such beads throughout all of prehistory, or did a "centralized mint" only appear at a certain point in time? If not, where else were shell beads produced? Finally, the research will also provide valuable paleoclimatic data on past changes in sea surface temperature and upwelling. Are conditions today similar to those in the past? If not, how have they changed through the millennia? Can we correlate other paleoenvironmental data (e.g., fishery production, vegetation, snowfall, etc) to ancient sea surface temperature and upwelling, so that we may better understand, and predict for the future, how changes in one affect the others?The investigators plan to incorporate the findings into an instructional module for school children at the Anthropology Museum at UC Davis, where over 500 K-12 school children visit each year. Children learn about pre-contact Native American lifeways and how archaeologists reconstruct the past from material remains. This module will show how technical-sounding analytical techniques (i.e., mass spectrometry) are used to answer simple-sounding questions (i.e., who traded with whom). Such outreach brings the past alive by providing interactive and hands-on experience with archaeologists and real artifacts.