Dating Methods and Chronology

Method of dating artifacts or occupation phases in relation to one another.
- Outcome: An artifact is classified as either older or younger than another.
C.J. Thomsen’s 3 Age System (19th century): A framework for categorizing artifacts into three ages: Stone, Bronze, and Iron.

Involves chronometric aging of an artifact or matrix, providing a fixed date.
- Key Method: Willard Libby Radiocarbon dating (introduced in 1949) as a method of absolute dating.

Agreed Measure of Time: Defined unit of measurement is the year.
- Fixed Points for Measurement:
- Year 1 starts from different historical events:
  - Christian (Gregorian) Calendar begins at AD (CE) 1.
  - Muslim Calendar begins at CE 622.
  - Greek Calendar begins at 776 BCE.
  - Mayan Calendar starts at 3114 BCE.
  - Egyptian Calendar Year 1 is based on the reign of each pharaoh.
- Terminology:
- BC – Before Christ
- AD – Anno Domini (in the year of Our Lord)
- CE – Common Era
- BCE – Before Common Era
- BP – Before Present, established at 1950.

Law of Superposition: Older layers lie beneath younger ones in undisturbed sedimentary deposits.
Build-up Layers: Natural and cultural formation processes lead to deposits over time.

Chronological Sequence of Geological Eras:
- Earth formation is dated to approx. 4.6 billion years ago.
- Paleozoic Era:
  - Cambrian: 541 million years ago
  - Ordovician: 485 million
  - Silurian: 443 million
  - Devonian: 419 million
  - Mississippian: 359 million
  - Pennsylvanian: 323 million
  - Permian: 299 million
- Mesozoic Era:
  - Triassic: 252 million
  - Jurassic: 201 million
  - Cretaceous: 145 million
- Cenozoic Era:
  - Paleocene: 66 million
  - Eocene: 56 million
  - Oligocene: 33.9 million
  - Miocene: 23 million
  - Pliocene: 5.3 million
  - Pleistocene: 2.6 million
  - Holocene: 11,700 years

Linking ‘Like with Like’ (Evans): Method of chronological ordering based on observable changes in shape, style, and technology of artifacts.
- Artifacts must have recognizable features that change over time.

Method of Chronological Ordering:
- Grouping assemblages (first developed by Petrie).
- Contextual Seriation: Duration and change observed in artifacts.
- Example: Flinders Petrie's sequential ordering of predynastic Egyptian pottery from Diospolis Parva, identifying seven successive stages with linked shapes.

Measurements based on proportional abundance or changes in frequency over time, often visualized through battleship curves.

Analyzes changes in language over time; measures similarity or differences.
- Lexicostatistics: Evaluates vocabulary changes.
- Glottochronology: Measures time period in years, often equated with absolute dating.

Defined through deep sea and ice core data utilization of oxygen isotopes:
- Isotopic Ratios:
- $^{16}O$ has 8 protons and 8 neutrons, comprises 99.76% of oxygen.
- $^{18}O$ has 8 protons and 10 neutrons, is 12% heavier than $^{16}O$ .
Foraminifera: Shells composed of calcium carbonate (CaCO3) that help in identifying historical climate periods.
Identifying glacial vs. interglacial periods based on isotopic ratios can provide climate data over millions of years, visualized as a saw tooth curve.

Palynology: Study of pollen to establish dates and ecological conditions.
- Pollen Zone Sequence: Identifies mixture of grasses versus trees indicating regional growth periods.
- Dating Range: 10,000+ years for Northern Europe; up to 3 million years in other regions.

Uses presence or absence of specific species to identify time periods.
- Extinct species that are pivotal to understanding periods of evolution and adaptation
- Examples:
  - Ice age camel (Camelops hesternus), ground sloth, shrub ox (Eucerotherium collinum), dire wolf, Columbian mammoth (Mammuthus columbi), saber-toothed cat (Smilodon fatalis), giant beaver (Castoroides ohioensis), American cheetah.
Molar Evidence:
- Specific molar characteristics can indicate time periods, for example:
- 8 plates = 4 million years ago; 23 plates = 10,000 BP.

This study guide covers the definitions and methodologies of relative and absolute dating, highlighting key techniques and principles in stratigraphy, typology, linguistic dating, climate analysis, and faunal dating, providing a comprehensive overview of chronological dating methods in archaeology.