(View exact match)Nderit DriftCATEGORY: site
DEFINITION: Site on the Nderit River south of Lake Nakuru, Kenya, which preserves a long sequence of archaeological deposits which illustrate the precursors of the Pastoral Neolithic complex. A blade industry of the 11th millennium BC is regarded as a probable ancestor of the Eburran (Gambles's Cave).cultural driftCATEGORY: term
DEFINITION: A gradual cultural change due to the imperfect transmission of information between generations; it is analogous to genetic drift in biology.driftCATEGORY: geology
DEFINITION: Any debris transported or deposited by or from glacial ice and meltwater; a glacial deposit laid down by ice or water in glacial streams, lakes, or arctic oceans. The term 'drift' remains in common usage and includes alluvium, pro-glacial deposits, till, and ice-contact stratified drift.
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DEFINITION: A replica of a balsa raft constructed by Thor Heyerdahl in 1947 to test the hypothesis that South American Indians could have drifted into Polynesia. This was the type of raft used in the 16th century AD along the coasts of Ecuador and northern Peru. He sailed the raft from South America to the Tuamotu Archipelago to show that Indians could have reached Polynesia. Archaeological evidence, however, has shown that any contacts were only of a minor nature.Lindholme HojeSYNONYMS OR RELATED TERMS: Lindholm Hills
DEFINITION: A site on the northern shore of Limfjord in Jutland, used as a gravefield from the prehistoric period until the Viking era, including a Viking ship cemetery. In the 11th century it was overlaid by a Viking village which functioned as a small trading and industrial settlement. One interesting find was a spoked wagon wheel. The settlement went out of use around 1100 due to the silting-up of the fjord and continual sand drifts.MesozoicCATEGORY: chronology
DEFINITION: The second of the Earth's three major geologic eras of Phanerozoic time and the interval during which the continental landmasses as known today were separated from the supercontinents Laurasia (North America and Eurasia) and Gondwana by continental drift. It occurred before the Cenozoic and after the Palaeozoic and was marked by the development of the ancestors of the major plant and animal groups that exist today and the extinction of the dinosaur, suddenly at the end of the Cretaceous Period. It lasted from about 245 to 66.4 million years ago and included, in order, the Triassic Period, the Jurassic Period, and the Cretaceous Period.flaking toolSYNONYMS OR RELATED TERMS: flaker
DEFINITION: A tool, such as an antler billet, or antler drift, which was used in removing flakes during the manufacture of a flaked stone projectile, tool, blade or artifact.magnetometerSYNONYMS OR RELATED TERMS: proton magnetometer
DEFINITION: A geophysical instrument that measures the intensity and sometimes direction of the Earth's magnetic field. It is used in electromagnetic surveying to identify changes in the field within soil or sediment that might be caused by subsurface features, hearths, kilns, or metal artifacts. When a current is passed through a coil in a bottle of water or alcohol the protons of the hydrogen atoms align themselves to its magnetic field. When the current is cut off, the protons realign themselves according to the earth's field, its strength being indicated by the frequency of their gyration on realignment. This sets up a weak current which is transmitted back from the bottle to the instrument and there registered on dials. The resulting figures are plotted to reveal anomalies in field strength - usually due to buried iron, kilns, hearths, or to pits or ditches. These features can thus be rapidly located without disturbance of the ground, and excavation can be directed to the most promising areas. Magnetrometry is the use of a magnetometer for mapping subsurface anomalies. There are a number of designs, but two are particularly widely used. The proton magnetometer makes an absolute measurement of field strength, but is intermittent in operation: each reading is initiated by the push of a button, and takes some seconds to appear on the display of the instrument. Fluxgate magnetometers work on a different principle, and give a continuous reading, which makes surveying less time-consuming. Most fluxgate machines do not however measure field strength directly, but rather are gradiometers, measuring the vertical gradient of the earth's' magnetic field, i.e. how fast the field strength changes with vertical distance from the earth's magnetic field Gradient measurements can also be used in archaeological surveys and have an advantage over absolute measurements. The earth's field strength varies continuously during the day at any one location. Absolute measurements taken at different times have to be calibrated for this effect if they are to be comparable. Gradient measurements are not affected by this diurnal drift in field strength, and so do not need to be calibrated. Proton gradiometers are also available. The fluxgate, differential fluxgate, and proton gradiometer take continuous measurements of relative vertical change in the intensity of field strength.paleomagnetismSYNONYMS OR RELATED TERMS: palaeomagnetism, remanent magnetism; paleo-magnetism, palaeo-magnetism; archaeomagnetism
DEFINITION: The magnetic polarization acquired by the minerals in a rock at the time the rock was deposited or solidified. The permanent magnetism in rocks, resulting from the orientation of the Earth's magnetic field at the time of rock formation in a past geological age. It is the source of information for the paleomagnetic studies of polar wandering and continental drift. The field of paleomagnetism involves techniques for determining the age of rocks by analyzing the magnetic field polarity of certain minerals in the rock and its importance in archaeology lies in its use as a dating method. The ancient orientation and intensity of the earth's magnetic field is preserved by the magnetization of iron oxides in rocks and sediments and archaeological materials (archaeomagnetism). Ancient direction and intensity of the earth's magnetic field may be preserved in three ways: a) thermoremanet magnetism (T.R.M.) works through the alignment of the magnetic domains within iron minerals when heated to above the Curie point and subsequently cooling, b) detrital remanent magnetism works through the alignment of clay particles sinking down slowly through still lake or deep ocean water. A block of sediment is magnetized in the direction of the earth's field at the time when it was deposited., and c) sun-dried bricks as the bricks become magnetized in the current direction and intensity of the earth's field. Using igneous rocks, independently dated by potassium/argon, and kilns, hearths, pots etc. dated archaeologically, it has been possible to reconstruct something of the history of the earth's magnetic field. Palaeomagnetism proper is done by studying reversals in the magnetic field of the Earth, the youngest reversal dating to 700,000 bp. Measurement of the declination and inclination of the magnetic poles as it affects materials of different ages can be used to build regional chronologies. Palaeomagnetic dating has also been successfully applied to lacustrine deposits, deep sea cores, and volcanic rocks.umiakCATEGORY: artifact
DEFINITION: A large, open boat used in Greenland and other Arctic peoples, made of seal or other animal skins stretched on a wooden (driftwood) or whalebone frame. It was called the woman's boat, as opposed to the kayak, the men's hunting and fishing boat. It was paddled and either round or elongated, like the birchbark canoe. The umiak was used by women for transporting themselves, children, the elderly, and possessions. It was also used by the men for whaling.