Term
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Definition
19th century, established 3 part organization of tools of Old World:
Stone, Bronze, Iron |
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Term
Relative Dating
(Indirect) |
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Definition
Idea that something is older or younger relative to something else
Expressed in terms of order.
Assignment of an age to a physical remain based on the association with other remains of known age.
Reliability of age: reliability of technique and association <= age assigned directly to sediments, provides an indirect age for physical remains of interest |
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Term
Absolute Dating
(Chronometric Dating) |
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Definition
How to know full or absolute age in years before present of different parts of the sequence.
Expressed in terms of unites.
Assignment of an age to a physical remain based on direct analysis of that physical remain.
Reliability of age = reliability of technique <= Age assigned directly to physical remains of interest => thing interested in dating. |
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Term
| Two biggest problems with Archae. dating methods |
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Definition
Not techniques themselves but:
1. Security of context i.e., ensuring the sample does relate securely to the context we are trying to date
2. Contamination of sample with more recent or older material |
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Term
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Definition
| Many dating methods provide results which form an age-bracket which can stretch over several centuries or even millenia |
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Term
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Definition
| Before Present, a way of standardizing years counted at 1950 AD so as to not be insensitive. |
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Term
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Definition
Two artifacts are buried at the same time within the same archaeo. deposit and can be no alter (no more recent) than the deposit itself
Allows to date a field site by dating an artifact because of association |
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Term
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Definition
Nitrogen, fluorine, uranium, collagen content, gradually reduced by process of chemical decay. Nitrogen content, for modern bone is 4%. Very variable, depends on site's chemical content as well.
Cannot form a basis of absolute dating, but on an individual site, chem, dating can distinguish bone on different age found in apparent stratigraphic association |
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Term
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Definition
1. Recognizable styles
2. Change in style is often gradual, evolutionary-like.
Sorting based on like goes with like.
Systematic organization of artifacts into types on the basis of shared attributes |
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Term
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Definition
| Based on chronological ordering of group of artifacts or assemblages, where the most similar is placed adjacent to each other in the series. |
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Term
Contextual Seriation
(Stylistic) |
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Definition
Duration of different artifact styles that governs seriation
Artifacts are arranged acc. to frequencies of their co-occurrence in specific contexts
Ordering of physical remains in a series so that adjacent items in the series are more similar to each other than items farther apart.
Don't know what is older or younger. |
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Term
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Definition
Relies on principally measuring changes in proportional abundance, or frequency, of ceramic style.
Ordering of artifacts according to their frequencies so that the distribution conforms to a "battleship-shaped" curve. |
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Term
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Definition
| Does not tell us which is first or last |
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Term
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Definition
| Applies to population events, not applicable to artifacts, or even samples of ancient DNA |
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Term
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Definition
| Language change, chronology. |
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Term
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Definition
| Part of linguistic dating, 100-200 words of vocab, compare them to other languages and their root words and score it to how similar it is. |
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Term
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Definition
| Part of linguistic dating, use a formula to pronounce measure of similarity and dissimilarities, how long ago in years it is since the two languages under consideration diverged. |
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Term
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Definition
Indestructible grains, preservation in bogs and lake sediments allowed pollen experts to construct detailed sequences of past vegetation and climate.
Can yield environmental evidence as far back as 3mya` |
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Term
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Definition
| Relies on the fact that many mammal species have evolved considerably over the last few million years |
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Term
| Varves and Lake Sediments |
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Definition
Thick layer: warm year with increased glacial melting
Thin layer: cold layer
Glacier sediment counting by year, reliable and can be linked to other varves for an expanded timeline |
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Term
Dendrochronology
(Tree Ring Dating) |
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Definition
Based on observation that the annual growth rings of a few tree species vary in width according to differences in seasonal growing conditions (esp. water availability)
Two uses:
1. Successful means of calibrating or correcting radiocarbon dates
2. Independent method of absolute dating in its own right.
Rings become narrower with age, amount of growth affected by fluctuations in climate
Sequence of tree-ring widths is perfectly unique to a sequence of growing seasons.
-Limitations
-Right species
-Seasonal variation
-Rings well preserved
-Sample > 30 rings
-Dated master sequence
-Sample context
-Direct dating (e.g. wood beam in a pueblo may date time of construction)
-Indirect dating (e.g. found in a deposit where cross-dating can be applied) |
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Term
| Limiting Factors of Dendrochronology |
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Definition
1. Applies to trees in regions outside tropics where pronounced differences btw. the seasons produce clearly defined annual rings
2. Restricted to wood from those species that have a.) yielded a master sequence back from the present and b.) people actually used in the past and c.) where the sample affords sufficiently long record to give a unique match. |
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Term
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Definition
Half life: 5730 Years
-Radiocarbon is produced in the upper atmosphere through the bombardment of 14N with cosmic and solar radiation
-14N + n -> 14C + 1H
All living organisms contain same amount of 14C as in the atmosphere. Also records from ANY organic material
Total amt of C does not change until organism dies, C decays
Max range of radiocarbon dating is appx. 9 half-lives.
Critical assumption: amount of radiocarbon produced in upper atmos. remained constant over time.
-NOT TRUE! More 14C in the past than today. |
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Term
| Error in Radiocarbon Samples |
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Definition
1. Contamination before sampling
2. Contamination during or after sampling
3. Context of deposition
4. Date of context |
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Term
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Definition
K-Ar: date rocks hundreds or even thousands of millions of years old. Appropriate for dating early human sites
Only viable radiometric technique for dating very old archaeological materials
Technique based on measuring the ratio 40Ar/40K in a sample
-Assuming that there is no 40Ar present at the beginning
-Ratio increases as age increases; 40Ar increases and 40K decreases as 40K decays
-Have to assume NO 40Ar in rocks... certain volcanic rocks that have been heated to melting point. |
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Term
| 40K Half Life, Error Estimate |
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Definition
1.3 billion years
Error estimate: 30,000 years |
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Term
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Definition
| Can help date teeth, etc., stalagmites/stalagtites because of calcium carbonate. |
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Term
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Definition
Earth's magnetic field is constantly changing, iron particles take up permanently the earth's magnetic direction at time of firing clay structures. Can date sites with clay quite accurately, or when something is out of context.
Every ~200ty |
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Term
Thermoluminescence Dating
(TL) |
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Definition
Two advantages:
1. Date pottery and rocks that have been heated at about 500ºC or higher.
2. Date inorganic materials beyond 50,000 of age.
HOWEVER: Very poor precision.
-Electron traps set to zero when heated. Increases with age. |
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Term
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Definition
Date minerals which have been exposed to light by several minutes' exposure to sunlight.
Drawback: some minerals don't capture sufficient amounts of sunlight, therefore are dated as older... very inaccurate. |
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Term
Electron Spin Resonance Dating
(ESR) |
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Definition
Less sensitive than TR, but better for dating materials that decay when heated.
Successful application: tooth enamel. Precision is 10-20%. |
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Term
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Definition
Based on principle that when volcanic obsidian is fractured, it starts absorbing water from its surroundings, forming a hydration layer that can be measured.
No universally valid rate of growth or hydration rate.
Obsidians from different quarries have different chemical compositions |
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Term
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Definition
Experimental stage. Used to date bone (only 10g required). Can be applied to material up to 100,000 years old, beyond time range of radiocarbon dating.
Bone preservation has enormous effect on apparent ages. Different aspects of bone has also different racemization rates. |
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Term
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Definition
Dating rock-art... kinda. Depends upon the accumulation of nuclides at/near surface of rock when exposed to cosmic radiation. One or two meters will block radiation. BUT when thick slabs of rock fall off....
Much higher if exposure is long.
Does not give info about date of a rock engraving, but about the length of time that the rock surface in Q has been exposed since the geological even leading to dating. |
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Term
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Definition
Small, independent sedentary communities without any strongly centralized organization.
Describing the first farmers. Mainly egalitarian communities. |
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Term
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Definition
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Term
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Definition
Order of strata from bottom to top represents temporal order of their deposition from oldest to youngest. (Below, older)
Layers get shifted- primary or secondary context?? DOES NOT tell you if site is primary or secondary. |
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Term
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Definition
| Natural sedimentary deposit layers that are organized in some sort of order (Z dimension) |
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Term
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Definition
Subdivision of stratigraphic record into sediments or rocks by means of fossil content
Evolution of characteristics one particular species
Development of new species |
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Term
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Definition
Sequence comparison
-Age assignment for a site or sequence of artifacts based on comparisons with a sequence of known relative or absolute age
-Assumes that process operating at undated spatial location are the same as that at the dated spatial location, or that the locations are connected.
-How reliable is dating method?
-How reliable are the associations?
-Assumes no time lag in between the two similar sites.
-CROSSCHECK EVERYTHING! Can't assume!!
-Some sequences cannot be cross dated based on sedimentary, soil, biostratigraphic or cultural similarities. |
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Term
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Definition
Measure of systematic error and refers to the "closeness" of a chronometric estimate to the true age
-Think a bulls-eye. The closer it is to the center, the more accurate it is.
-You have to know the true age… you have to have something outside the dating technique to assess the true age. |
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Term
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Definition
Measure of random error and refers to how often you arrive at the same answer for repeated dates (how often would you get the same answer?)
-Think a bulls-eye. The closer the clusters of multiple answers, the more precise it is. If the answers are very different from each other, then it is not precise. |
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Term
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Definition
| A subjective/objective determination of whether a date is representative of the "true" age |
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Term
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Definition
Refers to smallest unit of time at which two dates can be distinguishable
-My grandfather is an octogenarian, my grandmother is also an octogenarian. Who is older?
-You can only know if they fall within different decades worth of time.
-E.g., standard deviation of one date that can fall into one category. 1500 +/- 250 BP and 1490 +/- 250 BP is essentially the same thing.
-For relative stratigraphic dates, the resolution is determined by the thickness of the layers in the stratigraphic sequence. |
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Term
| Calendars and Historical Chronologies |
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Definition
High precision technique.
Only useful in literate times, usually complex societies and certain segments of society.
-e.g. Historical archaeology, Roman coins, Egyptian hieroglyphs, Mayan stelae, textual sources.
-To be used successfully, one must…
-Understand the date, literally (can you decipher it?)
-Understand what it dates (what is the literary context? factual or mythical?)
-Be able to translate it to a meaningful date referable to our time system (can the calendar be anchored in our calendar system?)
Written history throughout time. Must be sure that:
1. Chronological system requires careful reconstruction, list of rulers/kings must be reasonably complete
2. The list has to be linked with our own calendar if it is not to remain a "floating chronology"
3. Artifacts, features, or structures dated at a particular site have somehow to be related to the historical chronology, perhaps by association with inscription referring to ruler of time. |
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Term
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Definition
Application of a correction equation to convert radiocarbon years into calendar years
-Most reliable calibration based on:
-Dating of annual tree rings (but only goes back to ca. 13 ka)
-Dating of varved sediments
-Dating of fossil coral reefs using U-Th |
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