In June of 1867 — a few months before Alaska would become part of the United States with the transfer of $7.2 million to Russia — William Healey Dall picked up a shiny black rock from a riverbank.<\/p>\n
Dall was near the mouth of the Nowitna River, which flows into the Yukon River between today’s villages of Tanana and Ruby.<\/p>\n
He tucked away the interesting stone, scribbled a note about it in his journal, and continued on his expedition. His mission was to survey a possible route for a telegraph line along the Yukon River that might connect the U.S. with Europe via the Bering Strait.<\/p>\n
One-hundred-fifty-seven years later, while recently visiting Washington, D.C., Jeff Rasic held that same piece of obsidian in his hand.<\/p>\n
Rasic, an archaeologist and the science coordinator for all the 15 National Park Service units in Alaska, was at a gathering of colleagues in West Virginia. He had added a day to his trip from his home in Fairbanks to visit the Smithsonian Institution in Washington.<\/p>\n
There, he walked right to the institution’s geological collection to further explore one of his favorite projects: the sources of ancient obsidian tools found in Alaska.<\/p>\n
Obsidian is a black, often translucent rock. Volcanic eruptions sometimes ooze out magma that turns into this natural glass as it cools.<\/p>\n
Obsidian is hard, durable and can be worked to a razor-sharp edge. Archaeologists find it in sites all over Alaska where people once tipped spears, scraped hides and made knives with it. Far-north hunters also once implanted obsidian into the seats of their boats to draw whales to themselves.<\/p>\n
“It’s a fluke-of-nature rock,” Rasic said. “Because it’s such a rare thing, we can make a very precise match between the artifact and its source.”<\/p>\n
A good deal of the human-used obsidian in Alaska comes from a source called Batza Tena near the Indian River in Interior Alaska. There are a few other notable obsidian deposits, such as near Wiki Peak in the Wrangell Mountains, Okmok Caldera in the Aleutian Islands and sources in Southeast Alaska.<\/p>\n
Rasic is always on the lookout for samples of Alaska obsidian. He wants to pinpoint long-forgotten sources and learn what the rocks can tell us about interactions between ancient Alaskans.<\/p>\n
For example, he once linked an obsidian artifact from a 3,000-year-old site on Unalaska Island in the Aleutians to a source in the Wrangell Mountains, just a dozen miles from the Canada border.<\/p>\n
“To find something (in the Aleutians) from Interior Alaska was a big surprise,” Rasic said.<\/p>\n
How does Rasic tell the difference between Wiki Peak obsidian and obsidian from Okmok Volcano? He carries a hand-held machine that looks like a bar-code scanner.<\/p>\n
In the basement of the Smithsonian in Washington, Rasic pointed his machine at the black rock Dall had reported as a possible geological source. He pulled the trigger. The device sent out controlled beam of X-rays that excited electrons within the rock. That allowed Rasic to instantly know the concentration of elements in that piece of obsidian.<\/p>\n
Dall’s rock was a perfect match to Batza Tena, which makes sense in that the source is 70 miles from the beach where Dall picked it up.<\/p>\n
Rasic was pleasantly surprised to find that ancient people had worked this piece of obsidian, a rock he thought might have been from one of those unknown outcrops for which he is always searching.<\/p>\n
Dall’s obsidian was “evidently from a nearby camp, carried there by people with connections to the Koyukuk River and the Batza Tena source,” Rasic said. “I was happy to have solved a piece of the puzzle, and also for the chance to overlap in a small way with this noted explorer.”<\/p>\n
That naturalist and lover of Alaska left his name behind on more Alaska creatures and features than anyone else, including the Dall sheep and Dall’s porpoise.<\/p>\n
His name also remains on Dall Glacier, Dall Point, Dall Island, Dall Lake, Dall Mountain, Dall Ridge, Dall River and Mount Dall.<\/p>\n
• Since the late 1970s, the University of Alaska Fairbanks’ Geophysical Institute has provided this column free in cooperation with the UAF research community. Ned Rozell ned.rozell@alaska.edu is a science writer for the Geophysical Institute.<\/em><\/p>\n","protected":false},"excerpt":{"rendered":" In June of 1867 — a few months before Alaska would become part of the United States with the transfer of $7.2 million to Russia — William Healey Dall picked up a shiny black rock from a riverbank.<\/p>\n","protected":false},"author":106,"featured_media":111535,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_stopmodifiedupdate":false,"_modified_date":"","wds_primary_category":11,"footnotes":""},"categories":[11,6],"tags":[149,568,357],"yst_prominent_words":[],"class_list":["post-111534","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-home2","category-sports","tag-outdoors","tag-column","tag-nature"],"_links":{"self":[{"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/posts\/111534","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/users\/106"}],"replies":[{"embeddable":true,"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/comments?post=111534"}],"version-history":[{"count":0,"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/posts\/111534\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/media\/111535"}],"wp:attachment":[{"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/media?parent=111534"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/categories?post=111534"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/tags?post=111534"},{"taxonomy":"yst_prominent_words","embeddable":true,"href":"https:\/\/www.juneauempire.com\/wp-json\/wp\/v2\/yst_prominent_words?post=111534"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}