A Window on Ice Age Environment
Did Cave in Alaska's Lime Hills Shelter People 15,000 Years Ago?
A multidisciplinary team headed by Robert Ackerman of Washington State University is investigating the possibility of early human occupation in the Lime Hills region of south-central Alaska. Pending further funding, a team of archaeologists, geologists, a palynologist, and a zoologist will set out this summer to begin a three-year project of paleoenvironmental reconstruction. They believe that understanding the environment is the key to identifying and interpreting aspects of the human presence.
"When you study the context for humans in the Pleistocene, then you are dealing with a different environment, different vegetation patterns and different animals, and the adjustments for humans to the landscape would be different," Dr. Ackerman said in a recent telephone interview. He did a preliminary archaeological investigation in a cave in the Lime Hills region in June, 1993 with field support provided by the Alaska Division of Geological and Geophysical Survey.
Ackerman was contacted about possible cave sites there because he had done archaeological surveys in the Holitna and Hoholitna river drainages to the west of Lime Hills. Thomas Bundtzen of the Alaska Division of Geological and Geophysical Survey headed a research team mapping the geology of lands that were transferred from the federal government to the state of Alaska. During his 1992 geological survey Dr. Bundtzen found more than 50 shafts or caverns in the limestone topography east of the Stony River north of the community of Lime Village.
Having only 10 days to carry out field work, Ackerman immediately set out to determine if there were a human presence in a cavern Bundtzen thought would be the most promising archaeological site; it had been designated as Cave 1. Ackerman said the cave is about 1,700 feet in elevation at the eastern extreme of Lime Hills. He described it as having an opening two and a half meters high at its maximum and being about six and a half meters wide. From the entrance it extends into the hill more than 17« meters (58 feet). Dung and quills indicated that porcupines were the cave's current residents.
Ackerman made the initial excavations at the south side of the entrance: two adjoining one-by-one-meter test units, extending about two and a half meters back under the cave's shelter. These were excavated just over one meter deep without revealing a great deal of cultural evidence being recovered. "I found some bone that looked like it had perhaps cut marks on it, but that was it," he said.
Two separate one-meter-square test units were dug in the main corridor of the cave about one and three meters back from the drip line. These yielded artifacts made of organic material that included a bone or antler arrowhead with side-blade slots. These findings confirmed that preservation of bone and antler tools is possible in similar limestone caves of the Lime Hills region.
Charcoal and bone samples from the units were used for radiocarbon dating to determine the antiquity of the site. Two components were identified, indicating that there were two periods of occupation. The upper layer was found to contain artifacts of stone, bone and antler, and the lower component was found to contain a large amount of faunal remains. Technology combined with good luck provided the earliest dated artifact from the upper component. "While I was washing the [charcoal] sample I found a microblade in it," Ackerman said. "It couldn't get any better than that." The charcoal sample produced a radiocarbon age of 9,530 ñ 60 years B.P. (Beta 67667/CAMS 9896). That date and the presence of the microblade and the side-slotted arrowhead indicates that the cave occupancy was contemporary with the Denali complex of central Alaska, according to Ackerman's field report.
The artifacts, Ackerman says, demonstrate that around 9,000-10,000 years ago Denali complex people were using the bow and arrow. The recovery of a side-slotted bone arrowhead associated with the Denali complex assemblage at the Ilnuk site on the Holitna River, and H. Larsen's work at the Trail Creek site on Seward Peninsula, seem to back Ackerman's suggestion of such an early use of the bow and arrow.
"This is a very early use of it, and it's quite exciting because we have some idea what the microblades were used for." He points out that the bow and arrow is not known to have appeared in Washington until about 2,500 years ago.
Ackerman chose two samples of caribou bones and a bison bone to determine radiocarbon ages of the lower component of the Lime Hills Cave 1 site. He reported that the caribou bones were well preserved and provided satisfactory amounts of collagen for radiocarbon assay. One, a broken metapodial (shin bone) that he says possibly could have been a fleshing tool, was dated at 13,130 ñ 180 B.P. (Beta 67671). It was found 114 centimeters down in the outermost test unit in the cave's passageway. The other, a humerus bearing probable cut marks found at 91 centimeters in one of the earlier-excavated units, was dated at 15,690 ñ 140 B.P. (Beta 69669). More puzzling was a bison astragalus (ankle bone) from 70-77 centimeters down in one of the initial units; it yielded a date of 27,950 ñ 560 B.P. (Beta 67670). Ackerman reported that it must have been brought into the cave from a fossil locality. It was stained darker than other bones in the level.
Although the nature of the deposits in the lower component is not completely understood, Ackerman is certain there is enough evidence to warrant further research in the Lime Hills area. He has proposed a multidisciplinary approach that will target at least eight different facets that will provide a better understanding of the paleoenvironment of the Lime Hills and the place of humans within it.
Ackerman's proposal for the 1995 season:
Analyzing the stratigraphy of the caves;
Finding the bottom of the deposit in Cave 1;
Increasing the sample of faunal remains;
Increasing the sample of pollen;
Exploring the limestone ridge to find and correlate cave formations;
Arriving at a better understanding of the cave structure and the events that led to their formation;
Looking for more evidence of human occupation, especially stone tools.
Ackerman noted that these caves, because they are limestone and they preserve environmental information, present a unique opportunity to open a window on the Pleistocene. "Naturally we are hoping that we will find human evidence that takes us back into the Pleistocene. Even if we are not so lucky ... our paleoenvironmental data will still be tremendous."
--Robert W. Richards
ICE-AGE WISCONSIN PEOPLE LEFT UNIQUE CULTURAL RECORD
Complex Utilized Elephants, Caribou, Muskox
Investigations accomplished during the last few years have identified a distinct Paleoindian complex on the west side of Lake Michigan. After excavating two revealing sites near Kenosha, Wis., and studying lithic materials from more than 35 other sites nearby, Milwaukee archaeologist David F. Overstreet has proposed the name Chesrow Complex for a cluster of Paleoindian sites that are neither stylistically or typologically related to Clovis or Folsom. Chesrow, named for well-studied site at the south edge of Kenosha, seems to have been contemporary with late Clovis and Folsom about 11,000 years ago, although absolute antiquity remains uncertain.
Chesrow-complex sites occur on landscapes of the Lake Michigan lobe of the retreating glacial ice, while Paleoindian complexes related to Clovis and Folsom have been identified a short distance west on landscapes of the Green Bay glacial lobe. Chesrow complex does not contain exotic materials and the bifacially finished tools are highly variable, so much so that Dr. Overstreet initially thought he was seeing evidence of sequential occupations. "But I don't believe that anymore," he said in a recent telephone interview. He believes Chesrow was a relatively short-term occupation. The lithic materials, locally available glacial cobbles, were heat treated. By contrast, Clovis assemblages typically include lithics from distant sources.
The 1994 field season was important for confirming that Chesrow complex is associated with remains of extinct animals. Overstreet and his colleagues excavated the well-preserved bones of a disarticulated mammoth in direct contact with two stone tools. "The tools are certainly not Clovis. They're much more akin to Chesrow--small bifacial knives made on glacial cobbles-- purely local material," says Overstreet, who is president of Great Lakes Archaeological Research Center, a cultural resource management firm.
Though excavation of a butchered mammoth site and the delineation of a unique Paleoindian cultural record might seem exciting enough, Overstreet believes that environmental data might eventually be the greatest contribution of the archaeological sites near Lake Michigan in southeast Wisconsin. Analysis of evidence available or already gathered may eventually shed light on lingering questions about the human role in extinction of mammoths and mastodons.
However, a more basic question, the antiquity of the complex, remains to be settled. "I need to establish a very rigorous program of dating both the faunal remains and the site contexts," he explained, noting that there is little charcoal around in such old sites. Further, radiocarbon dating of bone collagen has been regarded with skepticism. But bone preservation from the sites is excellent and he expects to get several specimens dated by Thomas Stafford at the University of Colorado's Institute of Arctic and Alpine Research. "I've pulled together 14 well-documented specimens of mammoth, mastodon, caribou and muskox, and hopefully I'll get him to date all of it with his protocol," Overstreet said.
Because preservation of organic matter is so good in the southeastern Wisconsin sites, Overstreet says the locality is extraordinarily well suited to addressing many of the major issues in research relating to the Pleistocene-Holocene transition. However, the drainage and development projects that were responsible for the discovery of several of these sites are probably threatening still-undiscovered sites with deterioration as drying soils allow oxygen to reach buried organic materials.
"I think there's some urgency here," Overstreet said, discussing the cluster of sites in southeastern Wisconsin. He explained that the sites are associated with former glacial and post-glacial lakes that subsequently became wetlands, which were attracting duck hunters until the 1950s and 1960s. Gradually farmers extended their cultivation into the low, wet areas of muck soil by ditching and the installation of drain tile. Their ditching machines chanced upon some of the most spectacular faunal materials yet discovered including the Schaefer Mammoth (Mammoth Trumpet 8:4 "Mammoth Kill Dated 10,960") and the Hebior Mammoth, which Overstreet and colleagues recently excavated. Bone and other organic materials in the sites are beginning to be affected by oxygen, says Overstreet.
"I don't know what this holds for 20 years down the line," he adds. Though the archaeology of undisturbed Paleoindian sites is exciting, he believes that the overall picture of the environment at the Pleistocene-Holocene transition may be the most significant contribution of the Chesrow complex sites.
Besides dramatic bones of extinct megamammals, Overstreet points out that the locality offers well-studied stratigraphy and sedimentary deposits that can be correlated over considerable distances. "And there's wonderful organic preservation. Our excavations have recovered snails, clams, twigs, tree stumps, wood rafted up along former shore lines, insects, pond-weed seeds, needles of at least two species of pine, seeds, nut fragments, spruce cones and other organic remains." He notes that pollen, too, is well-preserved in the wet sediments.
Overstreet excavated the Chesrow site in 1986 and subsequently investigated lithic artifacts from several related sites. Chesrow lies alongside Sheridan Road in the village of Pleasant Prairie at the south edge of Kenosha. It is situated atop one of several old glacial-lake beach strands that parallel the present shore of Lake Michigan, which is about a mile to the east. It and other nearby sites have been known to artifact collectors since the beginning of the century. It had been placed on the National Register of Historic Places in 1977, but Overstreet's involvement began in 1985 when the municipality commissioned a study of the proposed right-of-way for a sewer line. His test excavations found undisturbed archaeological deposits and a Paleoindian fluted point.
After thorough excavations and analysis of material from the Chesrow site, Overstreet was left with the enigma of a Paleoindian occupation that had no obvious local or regional analog. "It flies in the face of conventional wisdom. This stuff doesn't seem to me to be closely related to Clovis, but somebody was hunting elephants in Southeast Wisconsin about 11,000 years ago." The Chesrow site revealed undisturbed Paleoindian features including a heat- treating kiln for processing raw material for stone tool manufacture. Less than a mile away at a discovery known as the Lucas site, he found completely undisturbed living floors with hearths, tools and calcined bone. "I hope to go back there again in the next couple of years."
These discoveries prompted three years of study of the region's lake-border moraines and glacial beaches, work partially funded by the National Parks Service through survey and planning grants administered by the State Historical Society of Wisconsin. Overstreet identified about 35 sites or components of Chesrow complex. "From this work I developed a preliminary settlement-subsistence model for the Chesrow complex with two site types: well-drained beach ridges of Glacial Lake Chicago, and so-called interior bog- margin sites in swales of Lake Border moraines."
Overstreet suggests that beach-ridge sites were well-situated to allow hunters to take advantage of possible caribou migrations. He notes that the lake shore would have formed a natural barrier to animals moving between summer calving grounds and winter forage areas. The interior sites, he suggests, were well- suited to exploitation of regional megafauna. Overstreet notes that Chesrow complex sites offer the opportunity to test current models of eastern Paleoindian subsistence that hold it unlikely that early people in Eastern North America exploited mammoths and mastodons.
Starting with the Schaefer Mammoth site, the focus of his research has turned more toward considering faunal and other environmental evidence. Schaefer was the first mammoth found in intimate association with stone tool material east of the Mississippi River. While archaeologists were excavating the Schaefer Mammoth, they learned of another farm-ditching project that had brought up a large bone fragment. That led to the Hebior Mammoth site, where excavation started last April, and concluded in November. With the bones of an adult male mammoth were some flakes, a crude chopper and two chipped stone knives.
Overstreet invited experts from other areas to visit the site while the stone tools were still in place. The mammoth material, he said, "is so tightly associated with bifaces right under the bones that I don't think anybody would argue that they're not contemporaneous." Vance Holliday, University of Wisconsin stratigraphy expert, and David Meltzer, Paleoindian authority from Southern Methodist University, looked and were convinced, Overstreet said. The mammoth sites, he said, raise many questions. Do the bone piles indicate active and systematic hunting? Or were the animals scavenged after dying under the stress of climatic transition? "Resolution of these questions will provide critical information for addressing the potential human role in extinction of mammoths on the North American continent," Overstreet said.
"The archaeology with undisturbed Paleoindian habitation sites and well- preserved megafauna is very exciting," Overstreet says. "However, I think the well-preserved pollen, plant macrofossils, gastropods and bivalves and insect remains, all in undisturbed sediments, are even more tantalizing. From continued research at this small basin and its associated pond sites, we hope to be able to provide a very comprehensive look at the end of the Ice Age, the relationship of human predation to extinction of megafauna, and the climatic conditions under which these events took place."
PRE-GLACIAL SITE IN ALBERTA SUGGESTS EARLY HUMAN PRESENCE
Investigators Agree on Need for Confirming Evidence
Archaeologists and geologists from the University of Alberta in Edmonton are examining evidence that people were in southwestern Alberta more than 20,000 years ago. Although initial results are regarded as promising, investigators concede that further work must be done at the sites to confirm preliminary results because the evidence bears directly on the highly controversial question concerning the antiquity of the peopling of the Americas.
The evidence consists of presumably artifactually flaked quartzite and hard limy siltstone cobbles found deeply buried in late Pleistocene geological contexts at two locations in the upper Bow River Valley on the western edge of the city of Calgary. The recovery of possible artifacts--flakes, cores and pebble tools, some found in situ below more than 20 meters of sediments of an Ice Age lake called Glacial Lake Calgary--strongly suggests early human activity there, says Jiri Chlachula, a researcher in Quaternary geology at the University of Alberta and principal investigator for the project he initiated.
At Varsity Estates or Site 1, investigations carried on since 1990 have yielded approximately 40 artifacts from an excavation of 15 square meters. About two kilometers upstream on the north side of the river valley, a second site, called Silver Springs, has yielded an assemblage of more numerous flakes. Artifacts are distributed there, mostly in a secondary position, at the base of till deposited by a valley glacier from the Rocky Mountains, presumably during the early portion of the late Wisconsin glacial stage. The stratigraphic position of the Silver Springs archaeological site indicates that people inhabited the area before the glacial advance that eventually overrode and severely disturbed the site. Although no radiocarbon dates are available, Dr. Chlachula said in a recent telephone interview that the glacial advance is assumed to have occurred between 25,000 and 21,000 years ago. He explained that after the Cordilleran glacier had retreated, the valley floor was reoccupied at Varsity Estates, as evidenced by the artifact assemblage excavated from the top of the till. This more recent occupation episode was disrupted during the maximum late Wisconsin glaciation by a southerly advance of the Laurentide ice sheet that dammed the Bow River and flooded the Varsity Estates site under the glacial lake.
Chlachula noted that work published last year by Alberta researchers provides a means for extrapolating a probable geological date for human occupation at the Varsity Estates site. The work by Robert R. Young of University of Calgary's Department of Geography, James A. Burns, paleontologist at the Alberta Provincial Museum, and three colleagues (See Suggested Readings) about 160 miles north of Calgary in central Alberta, has yielded radiocarbon dates ranging from 42,910 years B.P. to 21,330 years B.P. The researchers tested more than 30 samples of fossil mammal bones and wood from deposits beneath Laurentide glacial deposits. Chlachula said that another suite of nearly 40 radiocarbon dates on fossil bones from early postglacial deposits range from 11,600 to 9,000 years B.P. "The hiatus apparently dates the time when the first and only Laurentide ice-mass covered central Alberta and probably extended over parts of southwestern Alberta to dam the Bow River about 21,000 years ago and flood the Varsity Estates site," he told the Mammoth Trumpet.
Chlachula remains cautious but confident about the archaeological discoveries, agreeing that it would be good to have supporting dates from deposits that contain the artifacts. Such evidence could convince colleagues who may accept the archaeological evidence, as well as the geological context, but who still resist the idea that people were in the New World before 11,500 years ago--the conventionally accepted date for the entry of people from Asia into North America by way of the Bering land bridge.
Last year, Chlachula focused research on a third site with stone artifacts eroding from gravel deposits in a disturbed slope face. The researchers dug two pits through silts and gravel beds to try to establish a correlation with the two previous sites. "The geological context as well as the age of this site is not quite clear yet," Chlachula said of the third location. "So far, we are attempting to date indirectly only from the geological context. The results are very preliminary, and quite a lot of work is needed," he added. "Right now I'm hesitant to report on the latest site. More research is necessary to decide if there is some relation with the artifacts found in more definite geological contexts at the previous two sites. Some flakes and percussion-flaked pebbles have been found, but their approximate age has not been determined yet. Optically stimulated luminescence dating of samples we had taken last May may provide some clues." (See Mammoth Trumpet 9:3 "Measuring Energy Stored in Trapped Electrons")
There have been no discoveries of skeletal remains at any site, although spruce, pine and sedge pollen was recorded at Site 1 in the archaeological horizon. "I intend to expand the sections at Site 1 and Site 3 this summer," said Chlachula, who was born in Moravia in the former Czechoslovakia, and received his first doctorate in 1985 from Brno University in European archaeology, and a second doctorate in 1994 from the University of Calgary in archaeology. Research for his second Ph.D. was based on the study of the Calgary sites; Chlachula is now completing his Ph.D. in Quaternary geology at the University of Alberta focusing on Pleistocene environments in southern Siberia.
Nat Rutter, Professor of Quaternary Geology at the University of Alberta and Chlachula's supervisor, says that if both the archaeology and the geology are correct, it is a spectacular discovery. "I see nothing wrong with the interpretation of the geology," Dr. Rutter said in a telephone interview. He explained that the stratigraphic sequence is typical of western Canada. How old are the sites? Rutter said that there can be different interpretations of how the glacial till got over the top of the gravels that contain the artifacts. The sites may be as recent as 12,000-15,000 years old if till slumped off nearby melting ice during deglaciation. However, if the glacier advanced over the artifacts and the till was deposited off the bottom of the ice, it would mean the sites are much older, perhaps 21,000 years.
Though he leaves interpretation of the discoveries to archaeologists, Rutter supports the geology. "If those are artifacts, he's got a major find."
Jack Ives, Alberta's provincial archaeologist and assistant director at the Alberta Provincial Museum, has examined the artifacts and has seen other archaeologists react to them. He told the Mammoth Trumpet that many of the so- called artifacts are controversial, with some shown to have been created through natural forces working in a dynamic, high-energy glacial and river environment, and through modern fracturing of rock by earth-moving machinery. But Chlachula's archaeological experience in Europe and Siberia leaves him certain that some of them--unifaces as well as bifaces--are definitely prehistoric artifacts with traits similar to those produced on accepted stone tools of the late Pleistocene Paleolithic of northern Eurasia. Six flakes, found in a stratigraphically well-documented position below 24 meters of glaciolacustrine sediments, actually can be refitted onto one cobble biface, Chlachula said.
Dr. Ives believes it's better to remain skeptical until all the data are in. "The specimens collected from the sites certainly raise significant issues about how to tell natural from cultural breakage of stone, and many of the specimens could be natural," he said. But he agrees that one granular quartzite artifact Chlachula found at the Varsity Estates site is a bifacially created tool. "The specimen unquestionably looks like a biface--it has eight or nine alternating flakes creating good edge sinuosity along one side of the cobble. It would not be doubted as an artifact at Holocene-aged sites in Alberta." Ives noted that it is improbable that such an article was created naturally. "I can't feature this being a coincidence. It's very difficult to look at that biface and say 'that is not an artifact.'" But Ives pointed out that during the Pleistocene billions, if not trillions, of cobbles were being jostled and broken in the high-energy environments of the Bow River Valley, and naturally created "artifacts" or "eoliths" are not inconceivable. Apart from that biface, Ives said, many of the lithics are less convincing. He said he has seen a number of people react to Chlachula's assemblage and noted that some are willing to dismiss it because the raw material, granular quartzite, is almost like sandstone. Others, Ives added, are really happy with the raw material because it is friable enough that it couldn't stand any natural transport or banging around "without really coming unglued."
Alwynne Beaudoin, a paleoenvironmental research officer with the Provincial Museum of Alberta's Archaeological Survey, remains skeptical because during a short visit to the site she didn't notice a significant amount of evidence for soil development on the largely graveled surface. It is a surface that Ives called "a very inhospitable spot" for people to have been living.
"There was an absence of any evidence of any land surface or soil development, or indications of weathering," Dr. Beaudoin said in a telephone interview. That situation is difficult to account for, she said. "If it was a stable surface one would have expected to have found soil development of some kind and it is curious that we didn't notice any. It is one thing that needs to be explored a little further."
Despite criticism, Chlachula remains undaunted in his research. He believes that many of his critics wear blinders built by a narrow Clovis-first approach to Paleolithic archaeology. "I'm investigating and reporting on those sites as I would at any Pleistocene site in Eurasia," he said. "I know that some consider my work controversial, but that's not my problem--I don't. I realize that my claims on the early settlement of Alberta do not fit the established culture-historical scenario. Critics I have met so far tend to selectively use their arguments taken out of context against the Calgary sites by ignoring other lines of evidence." He says some of the objections show a lack of geological background and/or experience in early lithic technologies. Critics, he adds, often "try to operate with unfounded assumptions of natural glacial- fluvial flaking at the sites." Chlachula said he is quite familiar with the issues and that he dealt with them in detail in his dissertation.
"Overall, I do not think I have to be preoccupied with the 'Early Man' debate, which, in fact, I'm little interested in. Instead of simply talking and speculating about when and how prehistoric people came to America, I would rather do the basic field work. Once you have enough data, you can start putting together theories, but not vice-versa.
"As far as the ice-free corridor is concerned, it is not relevant for the work I'm doing," he said. "The corridor hypothesis relates to a traditional, conservative model of New World colonization at the very end of the Pleistocene by the Clovis culture. The archaeological data from the Bow Valley sites suggest that a settlement here in Alberta was earlier, established before the ice-free corridor existed."
--George Wisner
NEW BOOKS
The First Discovery of America: Archaeological Evidence of the Early Inhabitants of the Ohio Area. William S. Dancey, editor. ix + 212 8«-by-11-inch pages. $24.95 (paperback). The Ohio Archaeological Council, Columbus.
This book contains 12 papers presented in late November 1992 at The First Discovery of America: A conference on Ohio's Earliest Inhabitants. The chapters are grouped into four sections: Environmental Background, Paleoindian Studies, Early Archaic Studies, and Projectile Point Studies. "This book contains recently acquired archaeological data examined in original ways to kindle a rebirth of interest in research on the early inhabitants of Ohio between approximately 11,000 and 8,000 B.P.," editor Dancey, who is Associate Professor of Anthropology at The Ohio State University, says in the introduction.
The work of 22 contributors, some well-known to Mammoth Trumpet readers, is included. For example, David S. Brose of the Royal Ontario Museum describes archaeological investigations at the Paleo Crossing site, which has been confidently dated to 10,980 years B.P. In another chapter, Kenneth B. Tankersley of State University of New York, Brockport, examines the question of whether Clovis was a colonizing population. He argues that it was, but he notes that he does not conclude that it represented the first peopling of the continent. Curtis H. Tomak of the Indiana Department of Transportation describes the Alton Paleoindian site in Perry County, Ind., and Mark F. Seeman, Garry Summers, Elaine Dowd and Larry Morris compare fluted points from three of the largest Early Paleoindian sites in Ohio, Nobles Pond, Sandy Springs, and Welling. They argue that the three sites were functionally different. Evidence for butchery of the Burning Tree mastodon is presented by Daniel C. Fisher, Bradley T. Lepper, and Paul E. Hooge. They conclude that the cause of the mastodon's death is undetermined, but evidence suggests that it was hunted and killed by Paleoindians.
Papers in the volume are well illustrated with diagrams, maps, drawings and photographs.
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