My students, colleagues and I sought to (1) “[assess] the degree to which geological hazards in the Aleutian archipelago disrupted prehistoric human and ecological systems” and (2) to examine what types of rocks the prehistoric Aleutian peoples (Unangax) used for tools and what distances separated the possible quarry sites from the abandoned villages where our team found the tools. Our work multiplied the project funding to achieve project outcomes, scientific collaborations, and training for students far beyond what was originally anticipated.

Expanding scientific collaboration and monitoring volcanoes for public safety

We pioneered an extremely successful collaboration with the Alaska Volcano Observatory (AVO) and the U.S. Geological Survey (USGS) to collect data about how frequently IFM volcanoes erupted in the last ~10,000 years, including the time of prehistoric occupation, and to interpret what the data mean for the eruption frequency of IFM volcanoes today.

Training the next generation of geoscientists in interdisciplinary work

Our senior scientists provided vital interdisciplinary research training to nine undergraduates —five women and four men—who are entering graduate school in science, architecture, and medicine.

Building senior STEM leadership at Whitman College

Associate Professor Nicolaysen’s experience with this project strengthens her application for promotion to full professor, which would increase the gender diversity of senior science faculty at Whitman, where only two women now serve at that level.

RESULTS OF SPECIFIC STUDIES:

New understanding of the volcanoes of the Islands of Four Mountains

The geology team provided the first evaluation of the eruptive histories of the volcanoes Herbert, Carlisle, Cleveland (Chuginadak), and Tana. We discovered that volcanic ashes interrupted habitation of prehistoric, indigenous villages and that Tana and Herbert volcanoes are still steaming. This result led the USGS and AVO to consider reclassifying their potential for future eruptive activity.

What does a glacier on Tana volcano tell us about climate change in the last 4,000 years?

In 2015, we examined how water, gravity, glaciers, and other processes changed the surface landscape of the Islands of Four Mountains. Our results suggest that several advances and retreats of Tana glacier occurred during the last 3,700 years when Unangax inhabited the Islands of Four Mountains.

Prehistoric tools of the Unangax  

During the field research, the archeology and geology teams found that local, prehistoric people used lava, jasper, low quality opal, and obsidian (volcanic glass) for tools. Our chemical analyses led us to conclude that with a few exceptions the Unangax used a single obsidian resource for ~3700 years, that the primary obsidian is similar to local IFM lavas, and that obsidian from distant islands show significant differences to IFM tools. We are finishing our evaluation of the four, local, volcanic glass candidates in comparison to flakes from the sites by using two additional analytical techniques. 

Identifying hidden volcanic ashes and landslides in the village sites 

Student Loopesko used grain size analysis data and Scanning Electron Microscope (SEM) data from two villages to investigate whether debris flows (watery flood and landslide deposits) and small volcanic eruptions may have interrupted village occupations. She discovered clear indications of volcanic ash layers and cryptic (hidden) signals of human occupation like obsidian micro-flakes and bone fragments too small to be seen by the eye.

Identifying chemical signals of human occupation in village sites

The subsurface water that moves through the sediments of ancient Aleutians villages is rather acidic and eventually dissolves bone and shells from discarded Unangan food rubbish. Student Deacon and I hypothesized that dissolved bones and shells may leave a lasting but invisible record of human activity. Unusual levels of the chemical elements calcium, phosphorus, nitrogen, and carbon were detected in layers both below and from the floors and fill of pit houses in the IFM villages. 

Figure 1: The work sequence of student S. Sheffer over 10 months from the fieldwork in 2015 to her presentation at a conference in 2016. (a) Students Sheffer and Deacon sieved sediments collected from a nearby beach cliff that exposed eroding prehistoric village deposits. b) All types of lithic material found in one extraordinary day by archeology doctoral student Bruner. The shiny black flakes at the bottom left are obsidian. (c) Sheffer analyzes the chemical elements in the tools using a portable X-Ray Fluorescence (pXRF) spectrometer that does not damage the artifacts. (d) This scan of a thin piece of the natural glassy rock from Tana shows that the lower brown area is volcanic glass (obsidian). The small shapes throughout this are mostly crystals of plagioclase (a mineral of Ca, Al, Si, O) and would interfere with making excellent tools. (e) These data compare ratios of chemical elements and show that most of the obsidian tools clump together near the bottom of the graph. Many tools made of basalt lava and jasper/opal have different compositions.

Last Modified: 05/04/2017
Modified by: Kirsten Nicolaysen