Radiocarbon dating is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of carbon. The method was developed in the late 1940s by Willard Libby, who received the Nobel Prize in Chemistry for his work in 1960, it is based on the fact that radiocarbon is being created in the atmosphere by the interaction of cosmic rays with atmospheric nitrogen. The resulting 14C combines with atmospheric oxygen to form radioactive carbon dioxide, incorporated into plants by photosynthesis; when the animal or plant dies, it stops exchanging carbon with its environment, from that point onwards the amount of 14C it contains begins to decrease as the 14C undergoes radioactive decay. Measuring the amount of 14C in a sample from a dead plant or animal such as a piece of wood or a fragment of bone provides information that can be used to calculate when the animal or plant died; the older a sample is, the less 14C there is to be detected, because the half-life of 14C is about 5,730 years, the oldest dates that can be reliably measured by this process date to around 50,000 years ago, although special preparation methods permit accurate analysis of older samples.
Research has been ongoing since the 1960s to determine what the proportion of 14C in the atmosphere has been over the past fifty thousand years. The resulting data, in the form of a calibration curve, is now used to convert a given measurement of radiocarbon in a sample into an estimate of the sample's calendar age. Other corrections must be made to account for the proportion of 14C in different types of organisms, the varying levels of 14C throughout the biosphere. Additional complications come from the burning of fossil fuels such as coal and oil, from the above-ground nuclear tests done in the 1950s and 1960s; because the time it takes to convert biological materials to fossil fuels is longer than the time it takes for its 14C to decay below detectable levels, fossil fuels contain no 14C, as a result there was a noticeable drop in the proportion of 14C in the atmosphere beginning in the late 19th century. Conversely, nuclear testing increased the amount of 14C in the atmosphere, which attained a maximum in about 1965 of twice what it had been before the testing began.
Measurement of radiocarbon was done by beta-counting devices, which counted the amount of beta radiation emitted by decaying 14C atoms in a sample. More accelerator mass spectrometry has become the method of choice; the development of radiocarbon dating has had a profound impact on archaeology. In addition to permitting more accurate dating within archaeological sites than previous methods, it allows comparison of dates of events across great distances. Histories of archaeology refer to its impact as the "radiocarbon revolution". Radiocarbon dating has allowed key transitions in prehistory to be dated, such as the end of the last ice age, the beginning of the Neolithic and Bronze Age in different regions. In 1939, Martin Kamen and Samuel Ruben of the Radiation Laboratory at Berkeley began experiments to determine if any of the elements common in organic matter had isotopes with half-lives long enough to be of value in biomedical research, they synthesized 14C using the laboratory's cyclotron accelerator and soon discovered that the atom's half-life was far longer than had been thought.
This was followed by a prediction by Serge A. Korff employed at the Franklin Institute in Philadelphia, that the interaction of thermal neutrons with 14N in the upper atmosphere would create 14C, it had been thought that 14C would be more to be created by deuterons interacting with 13C. At some time during World War II, Willard Libby, at Berkeley, learned of Korff's research and conceived the idea that it might be possible to use radiocarbon for dating. In 1945, Libby moved to the University of Chicago, he published a paper in 1946 in which he proposed that the carbon in living matter might include 14C as well as non-radioactive carbon. Libby and several collaborators proceeded to experiment with methane collected from sewage works in Baltimore, after isotopically enriching their samples they were able to demonstrate that they contained 14C. By contrast, methane created from petroleum showed no radiocarbon activity because of its age; the results were summarized in a paper in Science in 1947, in which the authors commented that their results implied it would be possible to date materials containing carbon of organic origin.
Libby and James Arnold proceeded to test the radiocarbon dating theory by analyzing samples with known ages. For example, two samples taken from the tombs of two Egyptian kings and Sneferu, independently dated to 2625 BC plus or minus 75 years, were dated by radiocarbon measurement to an average of 2800 BC plus or minus 250 years; these results were published in Science in 1949. Within 11 years of their announcement, more than 20 radiocarbon dating laboratories had been set up worldwide. In 1960, Libby was awarded the Nobel Prize in Chemistry for this work. In nature, carbon exists as two stable, nonradioactive isotopes: carbon-12, carbon-13, a radioactive isotope, carbon-14 known as "radiocarbon"; the half-life
A midden is an old dump for domestic waste which may consist of animal bone, human excrement, botanical material, mollusc shells, sherds and other artifacts and ecofacts associated with past human occupation. These features, provide a useful resource for archaeologists who wish to study the diet and habits of past societies. Middens with damp, anaerobic conditions can preserve organic remains in deposits as the debris of daily life are tossed on the pile; each individual toss will contribute a different mix of materials depending upon the activity associated with that particular toss. During the course of deposition sedimentary material is deposited as well. Different mechanisms, from wind and water to animal digs, create a matrix which can be analyzed to provide seasonal and climatic information. In some middens individual dumps of material can be analysed. A shell midden or shell mound is an archaeological feature consisting of mollusk shells; the Danish term køkkenmøddinger was first used by Japetus Steenstrup to describe shell heaps and continues to be used by some researchers.
A midden, by definition, contains the debris of human activity, should not be confused with wind or tide created beach mounds. Some shell middens are processing remains: areas where aquatic resources were processed directly after harvest and prior to use or storage in a distant location; some shell middens are directly associated as a designated village dump site. In other middens, the material is directly associated with a house in the village; each household would dump its garbage directly outside the house. In all cases, shell middens are complex and difficult to excavate and exactly; the fact that they contain a detailed record of what food was eaten or processed and many fragments of stone tools and household goods makes them invaluable objects of archaeological study. Shells have a high calcium carbonate content; this slows the normal rate of decay caused by soil acidity, leaving a high proportion of organic material available for archaeologists to find. Edward Sylvester Morse conducted one of the first archaeological excavations of shellmounds in Omori, Japan in 1877, which led to the discovery of a style of pottery described as "cord-marked", translated as "Jōmon", which came to be used to refer to the early period of Japanese history when this style of pottery was produced.
Shell middens were studied in Denmark in the latter half of the 19th century. The Danish word køkkenmødding is now used internationally; the English word "midden" derives from the same Old Norse word. Shell middens are found in lakeshore zones all over the world. Consisting of mollusc shells, they are interpreted as being the waste products of meals eaten by nomadic groups or hunting parties; some are small examples relating to meals had by a handful of individuals, others are many metres in length and width and represent centuries of shell deposition. In Brazil, they are known as sambaquis, having been created over a long period between the 6th millennium BC and the beginning of European colonisation. European shell middens are found along the Atlantic seaboard and in Denmark and date to the 5th millennium BC, containing the remains of the earliest Neolithisation process. Younger shell middens are found in Latvia, the Netherlands and Schleswig Holstein. All these are examples where communities practiced hunting/gathering economy.
On Canada's west coast, there are shell middens that run for more than a kilometer along the coast and are several meters deep. The midden in Namu, British Columbia is over 9 meters deep and spans over 10,000 years of continuous occupation. Shell middens created in coastal regions of Australia by indigenous Australians exist in Australia today. Middens provide evidence of prior occupation and are protected from mining and other developments. One must exercise caution in deciding whether one is examining a beach mound. There are good examples on the Freycinet Peninsula in Tasmania where wave action is combining charcoal from forest fire debris with a mix of shells into masses that storms deposit above high-water mark. Shell mounds near Weipa in far north Queensland that are less than 2 meters high and a few tens of meters long are claimed to be middens, but are in fact shell cheniers re-worked by nest mound-building birds. Shell mounds are credited with the creation of tropical hardwood hammocks, one example being the Otter mound preserve in Florida, where shell deposits from Calusa natives provided flood free high areas in otherwise large watered areas.
There are instances in which shell middens may have doubled as areas of ceremonial construction or ritual significance. The Woodland period Crystal River site provides an example of this phenomenon; some shell mounds, known as shell rings, are open arcs with a clear central area. Many are known from Japan and the southeastern United States, at least one from South America; the word is of Scandinavian via Middle English derivation.
In the classification of Archaeological cultures of North America, the Woodland period of North American pre-Columbian cultures spanned a period from 1000 BCE to European contact in the eastern part of North America, with some archaeologists distinguishing the Mississippian period, from 1000 CE to European contact as a separate period. The term "Woodland Period" was introduced in the 1930s as a generic term for prehistoric sites falling between the Archaic hunter-gatherers and the agriculturalist Mississippian cultures; the Eastern Woodlands cultural region covers what is now eastern Canada south of the Subarctic region, the Eastern United States, along to the Gulf of Mexico. This period is variously considered a developmental stage, a time period, a suite of technological adaptations or "traits", a "family tree" of cultures related to earlier Archaic cultures, it can be characterized as a chronological and cultural manifestation without any massive changes in a short time but instead having a continuous development in stone and bone tools, leather crafting, textile manufacture and shelter construction.
Many Woodland peoples used spears and atlatls until the end of the period, when they were replaced by bows and arrows. The most cited technological distinction of this period was the widespread use of pottery, the diversification of pottery forms and manufacturing practices; the increasing use of horticulture and the development of the Eastern Agricultural Complex, consisting of weedy seed plants as well as gourd cultivation meant that groups became less mobile over time and, in some times and places, people lived in permanently occupied villages and cities. Intensive agriculture characterizes the Mississippian period from c. 1000–1400 CE and may have continued up to European contact, around 500 years ago. The Early Woodland period continued many trends begun during the Late and Terminal Archaic periods, including extensive mound-building, regional distinctive burial complexes, the trade of exotic goods across a large area of North America as part of interaction spheres, the reliance on both wild and domesticated plant foods, a mobile subsistence strategy in which small groups took advantage of seasonally available resources such as nuts, fish and wild plants.
Pottery, manufactured during the Archaic period in limited amounts, was now widespread across the Eastern Interior, the Southeast, the Northeast. The Adena culture built conical mounds in which single- or multiple-event burials cremated, were interred along with rich grave goods including copper bracelets and gorgets, art objects made from mica, hematite, banded slate, other kinds of stone, shell beads and cups, leaf-shaped "cache blades"; this culture is believed to have been core to the Meadowood Interaction Sphere, in which cultures in the Great Lakes region, the St. Lawrence region, the Far Northeast, the Atlantic region interacted; the large area of interaction is indicated by the presence of Adena-style mounds, the presence of exotic goods from other parts of the interaction spheres, the participation in the "Early Woodland Burial Complex" defined by William Ritchie Pottery was manufactured and sometimes traded in the Eastern Interior region. Clay for pottery was tempered with grit or limestone.
Pots were made in a conoidal or conical jars with rounded shoulders constricted necks, flaring rims. Pottery was most decorated with a variety of linear or paddle stamps that created "dentate" impressions, wavy line impressions, checked surfaces, or fabric-impressed surfaces, but some pots were incised with geometric patterns or, more with pictorial imagery such as faces. Pots were coiled and paddled by hand without the use of fast rotation such as a pottery wheel; some were brushed with red ochre. Pottery and permanent settlements have been thought of the three defining characteristics of the Woodland period. However, it has become evident that, in some areas of the United States, prehistoric cultural groups with a Archaic cultural assemblage were making pottery without any evidence of the cultivation of domesticated crops. In fact, it appears that hunting and gathering continued as the basic subsistence economy and that subsistence horticulture/agriculture did not occur in much of the Southeast for a couple of thousand years after the introduction of pottery, in parts of the Northeast, horticulture was never practiced.
This research indicated that a fiber-tempered horizon of ceramics predates 1000 BCE, first appearing about 2500 BCE in parts of Florida with the Orange culture and in Georgia with the Stallings culture. These early sites were typical Archaic settlements, differing only in the use of basic ceramic technology; as such, researchers are now redefining the period to begin with not only pottery, but the appearance of permanent settlements, elaborate burial practices, intensive collection and/or horticulture of starchy seed plants, differentiation in social organization, specialized activities, among other factors. Most of these are evident in the Southeastern United States by 1000 BCE. In some areas, like South Carolina and coastal Georgia, Deptford culture pottery manufacture ceased after c. 700 CE. In coastal regions, many settlements were near the coast near salt marshes, which were habitats ric
Santa Rosa-Swift Creek culture
The Santa Rosa-Swift Creek culture was characterized by the appearance of elaborate ceremonial complexes, increasing social and political complexity, mound burial, permanent settlements, population growth, an increasing reliance on cultigens. "Santa Rosa" is associated with the archeological site Santa Rosa Island, Santa Rosa County, Florida. "Swift Creek" is associated with the archeological site near Bibb County, Georgia. The Early Woodland Deptford culture evolved in place to become the Santa Rosa-Swift Creek culture. Burial mounds have yielded trade items which include copper panpipes, ear ornaments, stone plummets, stone gorgets; these show this area's incorporation within the Hopewellian Interaction Sphere by about AD 100. The Santa Rosa-Swift Creek culture extended over the western half of the Florida panhandle and adjacent parts of Alabama. Sites have been found around estuaries from St. Andrews Bay to Pensacola Bay, it is defined by a mixture of Swift Santa Rosa pottery types in village middens.
Four Santa Rosa-Swift Creek sites have been radiocarbon dated. Two sites in the Choctawhatchee Bay area have been dated to the period 150 to 450, while two sites in the Pensacola Bay area have been dated to the period 350 to 650; the dates for the Santa Rosa-Swift Creek culture in the Pensacola Bay area seem to indicate a adoption of the Santa Rosa-Swift Creek culture, as late Deptford ceramics have been dated to 260 in the Pensacola Bay area, but only to 150 in the Choctawhatchee Bay area. Santa Rosa ceramics appeared in both the Choctawhatchee Bay and Pensacola Bay areas by about 50 BCE. Deptford culture Swift Creek culture List of archaeological periods for North America
Paleo-Indians, Paleoindians or Paleoamericans is a classification term given by scholars to the first peoples who entered, subsequently inhabited, the Americas during the final glacial episodes of the late Pleistocene period. The prefix "paleo-" comes from the Greek adjective palaios, meaning "old" or "ancient"; the term "Paleo-Indians" applies to the lithic period in the Western Hemisphere and is distinct from the term "Paleolithic". Traditional theories suggest that big-animal hunters crossed the Bering Strait from North Asia into the Americas over a land-and-ice bridge; this bridge existed from 45,000–12,000 BCE. Small isolated groups of hunter-gatherers migrated alongside herds of large herbivores far into Alaska. From c. 16,500 – c. 13,500 BCE, ice-free corridors developed along the Pacific coast and valleys of North America. This allowed animals, followed by humans; the people used primitive boats along the coastline. The precise dates and routes of the peopling of the New World remain subjects of ongoing debate.
Stone tools projectile points and scrapers, are the primary evidence of the earliest human activity in the Americas. Archaeologists and anthropologists use surviving crafted lithic flaked tools to classify cultural periods. Scientific evidence links Indigenous Americans to eastern Siberian populations. Indigenous peoples of the Americas have been linked to Siberian populations by linguistic factors, the distribution of blood types, in genetic composition as reflected by molecular data, such as DNA. There is evidence for at least two separate migrations. From 8000–7000 BCE the climate stabilized, leading to a rise in population and lithic technology advances, resulting in more sedentary lifestyle; the specifics of Paleo-Indian migration to and throughout the Americas, including the exact dates and routes traveled, are subject to ongoing research and discussion. The traditional theory has been that these early migrants moved into Beringia between eastern Siberia and present-day Alaska 17,000 years ago, when sea levels were lowered due to the Quaternary glaciation.
These people are believed to have followed herds of now-extinct pleistocene megafauna along ice-free corridors that stretched between the Laurentide and Cordilleran ice sheets. Another route proposed is that, either on foot or using primitive boats, they migrated down the Pacific coast to South America. Evidence of the latter would since have been covered by a sea level rise of hundreds of meters following the last ice age. Archaeologists contend that Paleo-Indians migrated out of Beringia, ranging from c. 40,000 – c. 16,500 years ago. This time range promises to continue as such for years to come; the few agreements achieved to date are the origin from Central Asia, with widespread habitation of the Americas during the end of the last glacial period, or more what is known as the late glacial maximum, around 16,000–13,000 years before present. However, alternative theories about the origins of Paleoindians exist, including migration from Europe. Sites in Alaska are where some of the earliest evidence has been found of Paleo-Indians, followed by archaeological sites in northern British Columbia, western Alberta and the Old Crow Flats region in the Yukon.
The Paleo-Indian would flourish all over the Americas. These peoples were spread over a wide geographical area. However, all the individual groups shared a common style of stone tool production, making knapping styles and progress identifiable; this early Paleo-Indian period lithic reduction tool adaptations have been found across the Americas, utilized by mobile bands consisting of 20 to 60 members of an extended family. Food would have been plentiful during the few warm months of the year. Lakes and rivers were teeming with many species of fish and aquatic mammals. Nuts and edible roots could be found in the forests and marshes; the fall would have been a busy time because foodstuffs would have to be stored and clothing made ready for the winter. During the winter, coastal fishing groups trap fresh food and furs. Late ice age climatic changes caused plant communities and animal populations to change. Groups moved from place to place as preferred resources were depleted and new supplies were sought.
Small bands utilized hunting and gathering during the spring and summer months broke into smaller direct family groups for the fall and winter. Family groups moved every 3–6 days traveling up to 360 km a year. Diets were sustaining and rich in protein due to successful hunting. Clothing was made from a variety of animal hides that were used for shelter construction. During much of the Early and Middle Paleo-Indian periods, inland bands are thought to have subsisted through hunting now-extinct megafauna. Large Pleistocene mammals were the giant beaver, steppe wisent, musk ox, woolly mammoths and ancient reindeer; the Clovis culture, appearing around 11,500 BCE, undoubtedly did not rely on megafauna for subsistence. Instead, they employed a mixed foraging strategy that included smaller terrestrial game, aquatic animals, a variety of flora. Paleo-Indian groups carried a variety of tools; these included efficient fluted style spear points, as well as microblades used for butchering and hide processing.
Projectile points and hammerstones made from many sources are found traded or moved to new locations. Stone tools were traded and/or left behind fro