By Wayne Curtis
“It’s a huge area,” said Ashley Lemke. “It’s really deep. It’s really cold. And it’s hard to get to.” Lemke was talking about the Alpena-Amberley Ridge, a sizeable geological feature that lies about 100 feet beneath the surface of Lake Huron. The ridge runs in a northwest to southeast direction, and it once divided Lake Huron into two separate lakes. This terrestrial causeway attracted the attention of herds of caribou that migrated twice annually, moving north in the spring toward the grassy summer uplands, and south in the fall to more protected winter breeding grounds. In turn, the movement of those herds attracted the attention of early hunter-gatherers.
Lemke is an archaeologist at the University of Texas in Arlington and chair of the Advisory Council on Underwater Archaeology. For about a decade, she’s been studying this underwater ridge, which has been submerged for thousands of years. “It’s taken us a long time to put it all together,” she said, noting that, among other challenges, archaeologists can work in stints of only about twenty-five minutes at a time at those depths and temperatures. She and her colleagues are amazed by Alpena-Amberley Ridge. “It’s this perfectly preserved 9,000-year-old landscape with archaeological sites and pollen and rooted trees,” she said. It offers what she called a “Pompeiiesque” picture of hunter-gatherers at the end of the Pleistocene era.
A remotely operated vehicle (ROV) documents the exact location of a sample marker seen in the right corner at Alpena-Amberly Ridge. Researchers took sediment from the lake’s floor to examine it for archaeological evidence. | Credit: John O’Shea, UMMAA
A diver uses a portable air lift to collect a sediment sample at Alpena-Amberly Ridge. The sampled material is collected in a twenty liter container at the end of the lift tube, and sent to the surface via a lift bag. The sample will subsequently be screened and sorted in a laboratory at the University of Michigan. | Credit: John O’Shea, UMMAA
Rob Rondeau prepares an ROV for launching. He uses the ROV to search the seafloors of areas of the Pacific Northwest Coast for evidence of submerged archaeological sites. | Credit: Simon Fraser University
Underwater archaeology isn’t new. For decades, researchers have prowled ocean and lake bottoms using increasingly sophisticated equipment to locate and study shipwrecks ranging from prehistoric watercraft at the bottom of Irish lakes to the Titanic, at rest 12,500 feet below the surface of the Atlantic Ocean. But over the past two decades the techniques developed for discovering and probing sunken ships have aided archaeologists in investigating the submerged landscapes on which some of the wrecks are found. “The principal difference is with a wreck on the bottom, the landscape is incidental,” said John O’Shea, an archaeologist at the University of Michigan who pioneered studies of the Alpena-Amberley Ridge. “With prehistory, the landscape is everything.”
This is an article excerpt from the Spring 2022 edition of American Archaeology Magazine. Become a member of The Archaeological Conservancy for your complimentary subscription.