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·马雷恩博士将操作分析实验室，这些实验室将应用一种新的测年方法，使用从南非和欧洲的火山喷发出来的火山灰。在南非，Marean和Smith将确定一系列独特的人类特征何时在进化史上首次出现，从而帮助理解人类物种何时、何地和为什么进化。南非中石器时代(MSA)遗址通过推迟和丰富我们对科学认为对该物种具有决定性意义的关键特征的时间安排的知识，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，实验室将准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的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，产生年龄估计，而不是绝对日期。在过去，不同的实验室使用不同的模型，这可能会导致同一地质单位的不同年龄。这引发了一场约会争议，降低了人们对人类早期历史上关键事件的时间安排的信心。人们普遍认为，做出可靠的年龄估计的最好方法是使用几种独立的测年技术。最近，该团队在南部非洲的三个考古遗址中发现了火山灰，这些火山灰的化学成分最符合印度尼西亚7.4万年前的托巴火山喷发。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，并将南部非洲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。该项目不仅将为考古遗址提供一种新的独立测年工具，还将帮助培训学生和早期职业科学家掌握考古学和地质学的技术。Smith和Marean以及他们的研究团队将从南部非洲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，这些火山灰可能被用来准确测定早期人类历史上的重大事件，并将每个地点记录的早期人类历史与单一的测年模型联系起来。使用火山灰进行精确的年代测定将消除关于人类早期发育中关键事件时间的任何争论。火山灰与源火山的关联将使用火山灰的化学成分来完成。火山灰是被称为碎片的非常小的(微米大小)玻璃颗粒。这些颗粒由仪器分析，这些仪器将小直径的电子束或激光束聚焦在碎片上，以确定它们的化学组成。然后将这些化学物质与已知化学物质的数据库进行比较，以确定火山灰的来源和年代。这一裁决反映了NSF的法定使命，并通过使用基金会的智力优势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.