Radiometric dating, radioactive dating or radioisotope dating is a technique which is used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they were formed. The method compares the abundance of a naturally occurring radioactive isotope within the material to the abundance of its decay products, which form at a known constant rate of decay. The use of radiometric dating was first published in 1907 by Bertram Boltwood and is now the principal source of information about the absolute age of rocks and other geological features, including the age of fossilized life forms or the age of Earth itself, and can also be used to date a wide range of natural and man-made materials.
In archaeology, excavation is the exposure, processing and recording of archaeological remains. An excavation site or "dig" is the area being studied. These locations range from one to several areas at a time during a project and can be conducted over a few weeks to several years.
Geochronology is the science of determining the age of rocks, fossils, and sediments using signatures inherent in the rocks themselves. Absolute geochronology can be accomplished through radioactive isotopes, whereas relative geochronology is provided by tools such as paleomagnetism and stable isotope ratios. By combining multiple geochronological indicators the precision of the recovered age can be improved.
Thermoluminescence dating (TL) is the determination, by means of measuring the accumulated radiation dose, of the time elapsed since material containing crystalline minerals was either heated or exposed to sunlight (sediments). As a crystalline material is heated during measurements, the process of thermoluminescence starts. Thermoluminescence emits a weak light signal that is proportional to the radiation dose absorbed by the material. It is a type of luminescence dating.
Historical geology or palaeogeology is a discipline that uses the principles and methods of geology to reconstruct the geological history of Earth. Historical geology examines the vastness of geologic time, measured in billions of years, and investigates changes in the Earth, gradual and sudden, over this deep time. It focuses on geological processes, such as plate tectonics, that have changed the Earth's surface and subsurface over time and the use of methods including stratigraphy, structural geology, paleontology, and sedimentology to tell the sequence of these events. It also focuses on the evolution of life during different time periods in the geologic time scale.
Quaternary geology is the branch of geology that study developments from 2.58 million years ago to the present. In particular, Quaternary geology study the process and deposits that developed during the Quaternary, a period characterized by glacial-interglacial cycles. Quaternary geology has developed over time from being originally a branch of historical geology to becoming a science on its own.
An artifact or artefact is a general term for an item made or given shape by humans, such as a tool or a work of art, especially an object of archaeological interest. In archaeology, the word has become a term of particular nuance and is defined as an object recovered by archaeological endeavor, which may be a cultural artifact having cultural interest.
Gustav Oscar August Montelius, known as Oscar Montelius was a Swedish archaeologist who refined the concept of seriation, a relative chronological dating method.
Archaeological science, also known as archaeometry, consists of the application of scientific techniques to the analysis of archaeological materials and sites. It is related to methodologies of archaeology. Martinón-Torres and Killick distinguish ‘scientific archaeology’ from ‘archaeological science’. Martinón-Torres and Killick claim that ‘archaeological science’ has promoted the development of high-level theory in archaeology. However, Smith rejects both concepts of archaeological science because neither emphasize falsification or a search for causality.
Stratigraphy is a key concept to modern archaeological theory and practice. Modern excavation techniques are based on stratigraphic principles. The concept derives from the geological use of the idea that sedimentation takes place according to uniform principles. When archaeological finds are below the surface of the ground, the identification of the context of each find is vital in enabling the archaeologist to draw conclusions about the site and about the nature and date of its occupation. It is the archaeologist's role to attempt to discover what contexts exist and how they came to be created. Archaeological stratification or sequence is the dynamic superimposition of single units of stratigraphy, or contexts.
The Calico Early Man Site is an archaeological site in an ancient Pleistocene lake located near Barstow in San Bernardino County in the central Mojave Desert of Southern California. This site is on and in late middle-Pleistocene fanglomerates known variously as the Calico Hills, the Yermo Hills, or the Yermo formation. Holocene evidence includes petroglyphs and trail segments that are probably related to outcrops of local high-quality siliceous rock.
Absolute dating is the process of determining an age on a specified chronology in archaeology and geology. Some scientists prefer the terms chronometric or calendar dating, as use of the word "absolute" implies an unwarranted certainty of accuracy. Absolute dating provides a numerical age or range, in contrast with relative dating, which places events in order without any measure of the age between events.
In archaeology, a typology is the result of the classification of things according to their physical characteristics. The products of the classification, i.e. the classes, are also called types. Most archaeological typologies organize portable artifacts into types, but typologies of larger structures, including buildings, field monuments, fortifications or roads, are equally possible. A typology helps to manage a large mass of archaeological data. According to Doran and Hodson, "this superficially straightforward task has proved one of the most time consuming and contentious aspects of archaeological research".
Relative dating is the science of determining the relative order of past events, without necessarily determining their absolute age. In geology, rock or superficial deposits, fossils and lithologies can be used to correlate one stratigraphic column with another. Prior to the discovery of radiometric dating in the early 20th century, which provided a means of absolute dating, archaeologists and geologists used relative dating to determine ages of materials. Though relative dating can only determine the sequential order in which a series of events occurred, not when they occurred, it remains a useful technique. Relative dating by biostratigraphy is the preferred method in paleontology and is, in some respects, more accurate. The Law of Superposition, which states that older layers will be deeper in a site than more recent layers, was the summary outcome of 'relative dating' as observed in geology from the 17th century to the early 20th century.
In archaeology, seriation is a relative dating method in which assemblages or artifacts from numerous sites in the same culture are placed in chronological order. Where absolute dating methods, such as radio carbon, cannot be applied, archaeologists have to use relative dating methods to date archaeological finds and features. Seriation is a standard method of dating in archaeology. It can be used to date stone tools, pottery fragments, and other artifacts. In Europe, it has been used frequently to reconstruct the chronological sequence of graves in a cemetery.
Luminescence dating refers to a group of chronological dating methods of determining how long ago mineral grains were last exposed to sunlight or sufficient heating. It is useful to geologists and archaeologists who want to know when such an event occurred. It uses various methods to stimulate and measure luminescence.
Sequence dating, an archaeological relative dating method, allows assemblages to be arranged in a rough serial order, which is then taken to indicate time. Sequence dating is a method of seriation developed by the Egyptologist Sir William Matthew Flinders Petrie. By linking styles of pottery with different time periods, he was able to establish the relative chronology of the site.
Amino acid dating is a dating technique used to estimate the age of a specimen in paleobiology, molecular paleontology, archaeology, forensic science, taphonomy, sedimentary geology and other fields. This technique relates changes in amino acid molecules to the time elapsed since they were formed.
George Francis Carter was an American professor of geography who taught at Johns Hopkins University and later Texas A&M University. Carter had a background in anthropology and conducted archaeological excavations in Southern California. He is best known for supporting the theories of trans-cultural diffusion and early human settlement of the Americas.
This page is a glossary of archaeology, the study of the human past from material remains.
