A human jaw bone, recovered from a cave on northern Prince of Wales Island in Alaska's Tongass National Forest in early July 1996, has been radiocarbon dated at 9,730 +/- 60 years before present. "To my knowledge, these are the oldest reliably dated human remains ever found in Alaska," says James Dixon, curator of archaeology at the Denver Museum of Natural History, where the bones and artifacts are currently being studied. A tiny sample of bone from a break in the chin was treated by Thomas Stafford, Director of the Laboratory for Accelerator Radiocarbon Research at the University of Colorado-Boulder, before being submitted for dating to the Lawrence Livermore National Laboratory's Center for Accelerator Mass Spectrometry. Stafford feels an excellent sample was obtained from the jaw bone and that this is a very reliable date.
The cave, located in a remote area of southeast Alaska, was discovered in 1993 by cavers working with the Tongass Cave Project. During careful mapping of the passages, Kevin Alfred noted bear bones lying on the surface near the cave mouth. The bones were left in place until 1994 when Timothy Heaton, a paleontologist with the University of South Dakota-Vermillion was taken to the cave and collected two bear bones from eroding surface sediments in two different chambers. Then in 1996, accompanied by Fred Grady, preparator with the Smithsonian Institution, and supported by a grant from the National Geographic Society, Heaton spent two weeks carefully excavating a sample of the cave sediments. The team has recovered bear bones dating to 41,600 B.P. as well as seal bones dating to the peak of the ice age, 17,565 years ago. Seven other species of animals, no longer living on the island, have been discovered. "This cave has delivered one record-setting find after another," Heaton said. It was not until the last week of excavations in 1996 that the first evidence of human presence in the cave was discovered. In total, three artifacts (a stone spear point, a pointed bone tool, and a notched piece of bone) and five major skeletal elements (a lower jaw with teeth, three vertebrae, and a pelvis fragment showing signs of carnivore chewing) were found. As soon as the mud-covered bones were recognized as human, excavations were halted.
Under the terms of the Native American Graves Protection and Repatriation Act, immediately after discovery of the human skeletal material, Terry Fifield, archaeologist with the Tongass National Forest on Prince of Wales Island, began consultation with the tribal governments of Klawock, Craig, Hydaburg, and Kake to identify concerns and decide how to proceed. Both the Klawock Cooperative Association and the Craig Community Association passed resolutions supporting the analysis of the human bones and artifacts and agreeing to further excavations provided that the tribes were notified of any new discoveries. Both councils expressed some discomfort with analysis of the human bones and discussed their concern that increasing public interest in the caves of southeast Alaska poses a threat to sacred sites of the Tlingit and Haida people. However, in the end, both councils decided the potential to gain knowledge about some of their earliest ancestors was overwhelming.
The artifacts and human bones were sent to Dixon. For the past six years he and other researchers have been searching the caves of southeast Alaska for evidence indicating that humans first settled the Americas with the use of boats along the northwest coast of North America. The museum plans to continue its support of Dixon's research in southeast Alaska as this discovery develops. "I was delighted when we received the results of the radiocarbon analysis," said Dixon. "This may be just the tip of the iceberg. Future discoveries could be even older. It is my belief that some of the oldest archaeological remains preserved in North America will be found in the caves of southeast Alaska. This, and other discoveries, are critical to understanding when humans first came to the Americas, what the environment was like, and what their lives were like at that time. This discovery provides exciting new opportunities to scientifically demonstrate the long human occupation of southeast Alaska and to illuminate the rich cultural past of its people."
Further analysis of the bones and artifacts (radiocarbon dating, physical anthropological study, and other analyses) are planned. Excavation both outside and inside the cave is planned over the next few years. However, scientists, managers, and tribal members alike are concerned about the security of the cave. The fine, water-saturated silts that make up the cave floor are very vulnerable to damage, and the water-soaked bones and other organic materials contained in those silts are easily crushed. Jim Baichtal, geologist with the Ketchikan Area of the Tongass National Forest, stresses that the surfaces in these caves may not have been walked on by humans for millennia. When we enter these sites for the first time, we are altering or even destroying the accumulated record of thousands of years of environmental change in that area. Baichtal states, "These discoveries confirm the antiquity of the deposits within the caves. As explorers and researchers, we must recognize the potential importance of the paleoecological information contained in the sediments of the cave's floor and be careful with our disturbance. We all must take responsibility for protection of that information and what may be learned from it."
"We have seen a truly gratifying spirit of cooperation between tribal governments, federal agencies, universities, and scientists during the initial stages of this discovery," says Fifield. "In many ways this is a model of how we can work together on important concerns. We are optimistic that, as this discovery unfolds, we will continue to cooperate, sharing information and learning about the earliest beginnings of culture in southeast Alaska."
Terence E. Fifield is an archaeologist for the Thorne Bay and Craig Districts of the Tongass National Forest.