Ice Patch Archeology

August 05, 2016 Posted by: Caitlin Rankin

This season the archeologists at KLGO conducted the first ice patch survey in Southeast Alaska. Our archeologists are often asked about the difference between ice patches and glaciers. Unlike glaciers, ice patches have not accumulated enough mass to flow downhill. Glaciers are not well suited to preserve archeological material because the movement of ice destroys artifacts. Unlike glaciers, artifacts deposited in ice patches are preserved due to the stable nature of ice patches. The spatial extent of ice patches are determined by a balance of winter snow accumulation and summer melting. The trend of decreasing winter snow accumulation and increasing summer melting has resulted in irregular ice patch shrinkage and loss. 

View at snowy mountain pass with line marking former ice patch extent

Weathering of rocks provides some insights on the extent of ice patch melting. The lighter colored, less weathered rocks (blue line) indicate this ice patch was typically much larger. 

As these ice patches disappear, the artifacts preserved within are newly exposed to atmospheric elements that can rapidly destroy and degrade artifacts. The purpose of our survey is threefold:

  1. determine if ice patches in KLGO have preserved archaeological material;
  2. document and preserve any cultural resources;
  3. determine the extent of ice patch melting.
There are 277 identified ice patches within the boundaries of KLGO. Archeologists at KLGO do not have the ability to survey every ice patch within the park, so the first step in an archeological ice patch survey is to determine which ice patches are most likely to preserve artifacts. Before the Klondike Gold Rush, the Chilkoot Trail originally functioned as a trade route between native peoples living on the coast of Southeast Alaska and the interior. While utilizing the trade route, it is likely that traders would have exploited large game that ventured onto surrounding ice patches. Other ice patch studies in the neighboring Yukon Territory have found artifacts indicative of hunting activities such as wooden dart shafts, fletched wooden arrows, antler fore shafts, and butchered animal remains. With this expectation, KLGO archeologists targeted ice patches that were accessible from the trail and would have been visited by large game.

Computer generated relief map showing ice patches along the Chilkoot Trail
Ice patches (blue) along the Chilkoot Pass. Ice patch survey area near the summit outlined in yellow box.

The ice patch survey began with a two day trek to the summit of the Chilkoot Pass. With the cooperation of Park Canada, KLGO archeologists were able to camp at the summit to more easily complete the ground survey. Survey consisted of walking around the ice patches, looking for any materials that have recently melted out. Additionally, archeologists mapped the ice patches with a Trimble handheld GPS to determine the extent of ice patch melting. Five ice patches were surveyed in the middle of July.

Snow, rocks, and blue sky.
Two of the five ice patches surveyed in mid-July. box.

No pre-contact artifacts were discovered; however, some historic wood was documented. Traces of large game (hair, scat, and tracks) were found at every ice patch in the survey, confirming our expectation that game utilize these ice patches. KLGO archeologists will re-survey the ice patches at the end of July and middle of August to create a baseline of ice patch melting rates, and determine if any new artifacts are melting out of the ice patches. 

1 Comments Comments icon

  1. LARRY I
    December 02, 2017 at 08:01

    Although I am not an archeologist :P I found this survey along Chilkoot Pass quite interesting.

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Last updated: August 5, 2016

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