The gossip columns of newspapers and magazines are always full of the latest scoop on sports stars, rockers, and Hollywood celebs. I’m a great lover of gossip, but the juicy tidbits I like to know often take a little more digging than lifting the remote control. Lately, I’ve been wondering whether early humans in North America believed in Santa Claus. I wanted the scoop, the whole scoop, and nothing but the scoop, so I did some investigating. To my surprise, I discovered that thousands of years ago, in a landscape freshly exposed by a retreating ice sheet, hunters had strong opinions about Santa. They believed in him … with a vengeance. After 2.5 million years of ice age upon ice age, they were fed up with Santa’s antics and decided to strike where it hurt most – at his reindeer.
A paper released earlier this week by researchers at the University of Michigan marks the latest discovery in an archaeological adventure worthy of Indiana Jones. (Given the disappointment of the last Indiana Jones movie, it’s comforting to know that others have taken up the torch). Since 2008, the group has found more than 60 stone structures built by hunters 9,000 years ago. You might think it strange that they’ve uncovered so many artifacts in such a short timespan. Where in Michigan has nobody ever thought to look? Try at the bottom of Lake Huron.
Even from space, the Great Lakes stand out bright blue against the backdrop of North America
Lake Huron is the second-largest of the Great Lakes and the fourth-largest lake in the world. But it hasn’t always been this way. In fact, the Great Lakes are rather young, geologically speaking, formed by erosion of bedrock as a massive ice sheet traversed the landscape. Roughly 12,000 years ago, the ice retreated, leaving behind the vast basins that would become lakes Superior, Huron, Michigan, Erie, and Ontario. 9,000 years ago, the water level in Lake Huron was 100 meters (330 feet) lower than it is today, and a narrow land corridor known as Alpena-Amberley Ridge (AAR) spanned from northern Michigan to southern Ontario.
A view of present-day Lake Huron
This corridor was popular with the local traffic, serving as a route for caribou (reindeer) during their seasonal migration. And where the caribou walked, the hunters followed. Previous archaeological studies have shown that hunters were well-familiar with caribou behavior. In particular, they took advantage of the fact that caribou follow linear features, using wood and stone to channel the animals into corrals where they could be easily ambushed. The latest site is a driveway of sorts, measuring 8 m (26 ft) wide and 30 m (100 ft) in length. Raised cobble pavement along the edges guided caribou towards a stone cul-de-sac or enclosure. Stone blinds served as alcoves for hunters to hide unseen. Chipped stone flakes found within the enclosure show sharpened edges and signs of crushing – evidence of modification by primitive tools.
It seems strange to look for human history on a lake floor, but it is precisely the calm underwater environment that has preserved the sites so well. Similar intact sites have been found on land in the Canadian Arctic, but few in the Great Lakes region. The ridge’s location far from the lake shore has protected the sites from burial by sediments brought into the lake by rivers.
The research operation is a wonder in and of itself. Preliminary investigations are carried out by boats equipped with sonar systems. Like bats, the sensors emit a pulse of sound and use the signals reflected off the lake floor to form a map. A remotely operated vehicle (ROV) – an automated submersible – is then sent in to take video footage of the study area. When sites of interest require a ‘personal touch’, trained scuba diver-archaeologists are sent to assess the scene and take samples. If that’s not an adventure for Indiana Jones, I don’t know what is.
This video gives a short background on the Great Lakes, if you’re interested
Well, I don’t know about you, but that’s about as much gossip as I can handle for one week. Until next week, be warned: you may have just sustained a lethal dose of mostly harmless science.
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Cover photo courtesy of Johnny Peacock, Flickr Creative Commons. Other images from Wikimedia Commons.