106 37th Annual Undergraduate Research Exhibition Sponsored by Sigma Gamma Epsilon (Posters)

All students are encouraged to submit research to this poster session. Investigations from ANY geological subdiscipline are welcome. Presenters who are SGE members are eligible to compete for monetary awards distributed at the meeting.

Monday, 20 October 2025
8:00 AM - 5:30 PM
HBGCC, Hall 1

A Protracted Winter: Tree-Rings Indicate an Abrupt and Persistent Cooling in 1698 and 1699 CE, Gulf of Alaska

Paper number: 106-4
Program: Technical Sessions
Time: 8:00 AM – 8:00 AM

Authors

Abstract

Traditional oral histories from the Huna Tlingit of southeast Alaska chronicle an interval of extreme cold in their homeland, where winter abruptly succeeded the previous winter without an intervening summer. Shortly before or at this time, the Huna Tlingit people were forced off their homeland in Glacier Bay due to the advancing Sit’ Tlein glacier; however, the timing of this protracted winter is uncertain for the region.

Recent work in Northwest Europe has linked a volcanic eruption of unknown origin in the late 1690s to an extreme cooling event in the mid-high latitudes. Regional tree ring data characterizes the nature of this volcanic-induced cooling event in the context of the ongoing Little Ice Age (LIA, 1250-1850). The coldest summers identified in multiple European tree ring series are 1698, 1699, or 1700. This interval correlates strongly with extreme lows in tree ring latewood density data (a proxy for summer temperature) across much of the Northern Hemisphere; 1698 and 1699 are among the lowest densities, indicating cold summers. For Europe, the socioeconomic consequences of these coolings are evident in the approximately seven-year interval known as the “Ills” in Scotland during the 1690s. Although relatively well known in Northern Europe, this event and its effects on climate and human history have yet to be analyzed in the North Pacific sector.

A summer temperature-sensitive tree ring chronology based on Mountain Hemlock tree-ring series from the Gulf of Alaska (GOA), along with recently developed Alaskan cedar records, are consistent with NW European results. Tree ring indices in 1698, 1699, 1700, and 1701 are among the narrowest observed at several GOA locations. Tree-ring calendar dating of the advance of Sit’ Tlein glacier in Glacier Bay indicates that the Tlingit emigration from Glacier Bay likely occurred in the late 17th century. This timing is consistent with the oral history, indicating a protracted winter closely following the emigration. The late 1690s volcanic activity is a strong candidate for this reported cooling. Ongoing investigations of this event include the further characterization of this climate interval, which occurs during the Maunder Minimum, a period of increased volcanic activity, and an inferred negative shift of the Pacific Decadal Oscillation (PDO).

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-412514

© Copyright 2025 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.