Collaborative Research: Support for A Cryptotephra Laborators at UNLV and ASU

拉斯维加斯内华达大学的尤金·史密斯博士和亚利桑那州立大学的柯蒂斯·马里恩博士将管理分析实验室，利用火山喷发出的火山灰对南非和欧洲的考古遗址应用一种新的测年方法。在南非，马里恩和史密斯将确定一套独特的人类特征在进化史上首次出现的时间，从而帮助理解人类物种在何时、何地以及为何进化。南非中石器时代（MSA）遗址推翻并丰富了我们对科学认为确定物种的关键特征时间的认识，彻底改变了我们对现代人类起源的认识。在欧洲，利用火山灰，实验室将精确地确定现代人取代尼安德特人的时间。现代测年技术及其在考古遗址上的应用为确定早期人类历史上关键事件发生的时间提供了基础。这些技术使用复杂的模型来估算年龄，而不是绝对的日期。在过去，不同的实验室使用了不同的模型，这可能导致同一地质单元的不同年龄。这引起了一场日期争议，降低了人们对早期人类历史上关键事件时间的信心。人们普遍认为，产生可靠的年龄估计的最好方法是使用几种独立的年代测定技术。最近，研究小组在非洲南部的三个考古遗址中发现了火山灰，这些火山灰的化学成分与74000年前印度尼西亚多巴火山的喷发最为吻合。这一发现提供了一种独立的测年工具，可以与传统的测年方法一起使用，以解决测年争议，并将非洲南部这些遗址中保存的人类起源记录与现代人类起源的全球记录联系起来。这个项目不仅将为考古遗址提供一种新的独立的测年工具，而且将有助于培养学生和早期从事考古和地质技术的科学家。史密斯和马里恩以及他们的研究小组将从非洲南部和欧洲的考古遗址收集和处理样本，以识别和确定火山灰的分布，这些火山灰可能用于精确确定早期人类历史上重大事件的年代，并将这些遗址记录的早期人类历史与一个单一的年代模型联系起来。利用火山灰进行精确的年代测定将消除关于早期人类发展中关键事件发生时间的任何争论。火山灰与火山源的对比将利用火山灰的化学性质来完成。火山灰以非常小（微米大小）的玻璃颗粒的形式存在，被称为碎片。这些颗粒通过将小直径的电子束或激光束聚焦在碎片上的仪器来分析，以确定它们的化学成分。然后将化学成分与已知化学成分的数据库进行比较，以确定灰烬的来源和年龄。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Dr. Eugene Smith of the University of Nevada, Las Vegas and Dr. Curtis Marean of Arizona State University will operate analytical laboratories that will apply a new dating method using ash erupted explosively from volcanoes to archaeological sites in South Africa and Europe. In South Africa, Marean and Smith will determine when a suite of uniquely human features first appeared in the evolutionary history and thus help understand when, where and why the human species evolved. South African Middle Stone Age (MSA) sites have revolutionized our knowledge of modern human origins by pushing back and enriching our knowledge of the timing of key features science considers definitive for the species. In Europe, using volcanic ash, the laboratories will precisely date the timing of when modern humans replaced Neanderthals. Modern dating techniques and their application to archaeological sites provide the basis for determining when key events in early human history occurred. These techniques use complex models that produce age estimates and not absolute dates. In the past, different laboratories have used different models that may result in different ages for the same geologic unit. This has created a dating controversy that reduces confidence in the timing of key events in early human history. There is general agreement that the best way of producing robust age estimates is to use several independent dating techniques. Recently, the team identified volcanic ash in three archaeological sites in southern Africa, and the best fit of the chemistry of this ash is to the 74,000-year-old eruption of the Toba volcano in Indonesia. This discovery provides an independent dating tool that can be used along with traditional dating methods to resolve the dating controversy and tie the record of human origins preserved in these sites in southern Africa to the global record of modern human origins. This project will not only provide a new independent dating tool for archaeological sites but will help train students and early career scientists in the techniques of archaeology and geology.Drs. Smith and Marean and their research team will collect and process samples from archaeological sites in southern Africa and Europe to identify and determine the distribution of volcanic ash that may be used to precisely date major events in early human history and to tie early human history recorded at each of these sites to a single dating model. Precise dating using volcanic ash will remove any debate about the timing of key events in early human development. Correlation of volcanic ash to source volcanoes will be done using the chemistry of the ash. The ash is in the form of very small (micron-sized) glass grains known as shards. These grains are analyzed by instruments that focus a small-diameter electron or laser beam on the shard to determine their chemical makeup. The chemistry is then compared to a database of known chemistry to identify the source and age of the ash.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.