Geologic and Anthropologic Histories of the Kuril Islands, Russia

1. Geologic and Anthropologic Histories of the Kuril Islands, Russia Amy Tice, Senior, Earth and Space Sciences, Anthropology Mentor: Joanne Bourgeois, Earth and Space Sciences • Research Goal: To use tephra to tell time in archaeological and geologic excavations. Osma Profile Courtesy of Bre MacInnes Introduction A team of researchers, including geologists, measured stratigraphic sections and took samples of tephra from various locations throughout the Kuril islands. My research involves analyzing tephra to gain a better understanding of the volcanic eruption history. View from Ainu Creek tephra sample ←Osma Profile This profile shows the Osma Point 19 excavation in context with the topography and other stratigraphic columns taken along a transect. Photo Courtesy of Ben Fitzhugh Surface 1899 +/- 6 AD 1689+/- 3 AD ↑Tephra layer ↑Archaeological layer 50 cm 1480 +/- 10 ↓ AD 100 cm Kapsyul Cape Roadcut 1 Ainu Creek – Uphill Osma Marsh Vasino Test Pit 1 Kapsyul Cape 3m Beach Osma Point 19 ↑Location:The Kuril Islands are located on the Pacific Ring of Fire and are volcanically active. I am looking specifically at the southern end of Urup Island at three sites: Ainu Creek/Vasino, Kapsyul Cape, and Osma. Stratigraphy Stratigraphy is the study of the strata (layers) which sediments form as they deposit. Geologists dig excavations and describe the layers, then use charts like this to correlate the layering between columns. Using information I found from analyzing tephra, I have drawn tie lines between layers which belong to the same volcanic event. Now I can represent the entire study area using only the information from a few stratigraphic columns. Marker Tephra 1 Photo Courtesy of Ben Fitzhugh Marker Tephra 2 ↑This is an example of an excavation that has a layer of tephra and a layer of archaeological material. Because the tephra is positioned above the archaeological layer, it is younger than the archaeological material. Marker Tephra 3 Marker Tephra 4 Analyzing Tephra (Volcanic Ash) When volcanoes erupt, they eject millions of tons of material into the air. The airfall material is called tephra, or volcanic ash, and consists of rocks, minerals, and glass. Each volcanic eruption ejects different proportions of these materials, and by comparing the proportions one can recognize if tephra samples came from the same or different eruptions. Uncorrelated Tephra ← Kapsyul Cape 3m Beach Tephra This is an example of what tephra can look like under a microscope. This is the fine portion of the sample and consists mostly of volcanic glass, with a few minerals and very few lithic fragments. • Conclusion and Future Work • I was able to make tephra correlations and identify important marker tephra in the South Urup region. However, work is needed to fill in the story of the island further: • Continue to compare tephra samples • Correlate tephra with radiocarbon dates • Compare dates with historical information For more information please visit the Kuril Biocomplexity Project website at: http://depts.washington.edu/ikip/index.shtml