24 Undergraduate Research Posters

This poster session highlights geoscience research conducted and presented by undergraduate students. Abstracts must be written by students (but may include non-student co-authors). Research topics may include any area of the earth sciences.

Thursday, 23 April 2026
8:00 AM - 5:30 PM
LMH, 5th Floor Chapel

17th Century Volcanic-Induced Cooling Signaled by Tree Ring Growth, Gulf of Alaska

Paper number: 24-13
Program: Technical Sessions
Time: 8:15 AM – 8:15 AM

Authors

Abstract

Oral histories from the Huna Tlingit people of southeast Alaska chronicle an interval of extreme cold, when winter succeeded winter without an intervening summer. At around this time, the advance of the Sit’ Tlein glacier forced the Huna Tlingit from their homeland in Glacier Bay, but the timing of this protracted winter and glacial advance is uncertain.

Recent work in Scotland has linked volcanism in the 1690s to an extreme cooling event in the mid-to-high latitudes; the coldest summers identified in multiple European tree-ring series are 1698, 1699, and/or 1700. Researchers suggest that eruptions in the years 1693 and 1695 were the likely cause of the 1698/99 cold period documented along 55-60°N latitude in Scotland. However, this event has not yet been analyzed in the mid-high latitudes in the North Pacific region.

We analyzed tree ring data from Mountain Hemlock (MH) and Yellow Cedar (YC), two temperature-sensitive species near Juneau in southeast Alaska, to provide insight into temperatures from 1550 to 1850 CE. We selected 13 locations (7 YC and 6 MH), with a combined mean sample size of approximately 300 trees during the 300-year window of interest. These trees, proximal to the Gulf of Alaska (GOA), preserve temperature signals in their ring widths, which respond to mean temperature during the growing season (June-August). 

Trends in MH and YC ring thicknesses correlate strongly with the volcanic-induced cooling events previously documented in Scotland. In both the MH and YC chronologies, 1698 is the second-narrowest tree ring width, and our data reveal several other notable cooling events preserved in the chronologies, including 1572 and 1811, likely caused by dated volcanic eruptions. However, our tree-ring-width temperature reconstructions reveal a more prolonged period of cold, with 1697-1701, 1698-1702, and 1702 -1706 among the 10 coldest five-year periods for both species across the 300-year window analyzed in this study. 

Although the 1698/99 interval is a strong candidate for the “winter following winter” documented in Huna Tlingit oral histories, it is possible that the longer period of cold we document in this study was responsible for rapid advance of the Sit’ Tlein glacier and resulting migration of the Huna Tlingit people. We are investigating data correlations with Sea Surface Temperature, ENSO, and/or the Pacific Decadal Oscillation.

Geological Society of America Abstracts with Programs. Vol. 58, No. 3

doi: 10.1130/abs/2026CD-410959

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