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Intro to Archaeology
Table of Contents
Unit 6 Overview: Dating Methods in Archaeology
6.1 Relative Dating Techniques
6.2 Radiometric Dating Methods
6.3 Other Absolute Dating Methods
6.4 Limitations and Challenges in Archaeological Dating

Archaeologists use various techniques to determine the age of artifacts and sites. Stratigraphy, seriation, typology, and cross-dating help establish relative chronologies without exact dates. These methods rely on layering, style changes, and comparisons between sites.

Understanding these principles is crucial for piecing together the past. By analyzing how objects and layers relate to each other, archaeologists can reconstruct sequences of events and cultural changes over time, even without precise dates.

Principles and Techniques of Relative Dating

Principles of stratigraphy in archaeology

  • Stratigraphy studies layered deposits (strata) to establish relative chronology
    • Law of Superposition: in undisturbed sequences, older layers deposited first and overlain by younger layers
    • Allows establishing relative age of artifacts and features within a site (pottery, tools)
  • Stratigraphic relationships determine sequence of events and changes over time
    • Intrusive features (pits, burials) cutting through older layers are younger than disturbed layers
    • Fill of intrusive features younger than feature itself and surrounding strata
  • Harris Matrix diagrams stratigraphic relationships and relative chronology of a site
    • Visualizes and analyzes complex stratigraphic sequences (Pompeii, Çatalhöyük)

Seriation for chronological sequencing

  • Seriation arranges artifacts in chronological sequence based on changes in attributes over time
    • Assumes artifact styles and characteristics change gradually and continuously in particular direction (pottery decoration, tool shape)
  • Frequency seriation arranges artifact types based on relative frequencies or proportions in different assemblages
    • Relies on idea that certain artifact types become more or less common over time
  • Contextual seriation considers stratigraphic and spatial context of artifacts within a site
    • Refines chronological sequences and identifies contemporaneous assemblages
  • Seriation particularly useful for dating artifacts and sites lacking absolute dating methods (prehistoric sites, early civilizations)

Typology in relative dating

  • Typology classifies artifacts into distinct types based on physical attributes
    • Assumes artifacts of same type are contemporaneous and reflect specific time period or cultural tradition (projectile points, ceramics)
  • Typological sequences establish relative chronologies and trace cultural changes over time
    • Requires understanding of regional and temporal variations in artifact styles
  • Limitations of typology in relative dating:
    • Typological sequences may not always reflect true chronological order
      • Some artifact types can persist for long periods or be reused
    • Regional variations and cultural differences complicate use of typology across different sites and areas
    • Typology alone cannot provide absolute dates, requires additional dating methods for more precise chronologies

Cross-dating for site correlation

  • Cross-dating compares and correlates archaeological finds from different sites using multiple dating methods and evidence
    • Establishes synchronicity and contemporaneity of artifacts and features across a region (trade goods, architectural styles)
  • Stratigraphic cross-dating correlates strata and features between sites based on relative position and associated artifacts
    • Requires careful comparison of stratigraphic sequences and diagnostic artifacts
  • Typological cross-dating compares artifact types and styles across sites to establish relative chronologies
    • Assumes similar artifact types are contemporaneous and reflect cultural connections or influences
  • Other cross-dating methods include absolute dating techniques (radiocarbon dating) and historical sources (written records, coins) to anchor relative chronologies
    • Provides independent age estimates to correlate and refine relative dating sequences across sites (Mayan sites, Roman provinces)

Key Terms to Review (19)

Law of Superposition: The law of superposition is a fundamental principle in geology and archaeology stating that in any undisturbed sequence of sedimentary rock layers or archaeological deposits, the oldest layers are at the bottom, and the younger layers are at the top. This principle helps to establish a chronological order for geological events and artifacts, allowing archaeologists to interpret the relative ages of findings based on their position within the stratigraphic sequence.
Chronological sequence: A chronological sequence is the arrangement of events or artifacts in the order they occurred over time. This concept is vital in understanding the progression of human activity and the development of cultures, as it helps archaeologists reconstruct past events and establish a timeline of historical significance. By organizing findings chronologically, researchers can better analyze relationships and influences across different periods.
Site stratigraphy: Site stratigraphy refers to the study of the layers of soil and sediment at an archaeological site, providing a record of its chronological sequence. Each layer, or stratum, represents a specific time period and helps archaeologists understand the relationship between artifacts and their context in time and space. By analyzing these layers, archaeologists can reconstruct past human activities and environmental changes.
Stratigraphic relationships: Stratigraphic relationships refer to the layers of sediment or rock that are deposited over time, which help archaeologists and geologists determine the relative ages of different layers and the artifacts or fossils within them. Understanding these relationships is essential for establishing a timeline of past events, as it allows researchers to analyze how layers interact and change over time due to natural processes like erosion, sedimentation, and tectonic activity.
William F. Libby: William F. Libby was an American chemist who developed the radiocarbon dating method in the late 1940s. This groundbreaking technique revolutionized archaeology and other fields by allowing researchers to accurately date organic materials up to about 50,000 years old, thereby providing a chronological framework for studying past human activities.
Cultural changes: Cultural changes refer to the transformation in the beliefs, practices, norms, and values of a society over time. These shifts can occur due to various factors such as technological advancements, interactions with other cultures, and social movements, leading to significant alterations in lifestyle, art, and social structure.
Cultural layers: Cultural layers refer to the distinct levels of sediment and artifacts found at an archaeological site, representing different periods of human activity and societal development. Each layer provides valuable information about the people who lived there, their behaviors, and how their culture evolved over time. By studying these layers, archaeologists can establish a timeline of occupation and understand changes in technology, economy, and social organization.
Typological Sequences: Typological sequences refer to a method in archaeology that organizes artifacts into a chronological order based on their shared characteristics, styles, or functions. This approach allows archaeologists to make relative dating assessments by comparing similar items from different contexts, ultimately helping to reconstruct historical timelines and cultural changes.
Contemporaneous assemblages: Contemporaneous assemblages refer to groups of artifacts or features that were created or used during the same time period at a specific archaeological site. These assemblages are crucial for understanding the cultural and social dynamics of a community as they provide insights into the daily lives, technologies, and interactions of people living in that time frame.
Artifact types: Artifact types refer to the various categories or classifications of objects created or modified by humans that archaeologists study to understand past cultures and behaviors. These classifications help researchers identify the function, usage, and cultural significance of artifacts found at archaeological sites, allowing them to piece together historical narratives and contexts.
James Hutton: James Hutton was an 18th-century Scottish geologist, often referred to as the 'father of modern geology.' His work laid the foundation for understanding geological processes and time, significantly influencing the development of relative dating techniques by proposing that the Earth is shaped by the same natural processes still in operation today, a principle known as uniformitarianism.
Artifact association: Artifact association refers to the relationship between different artifacts found at an archaeological site, providing context about how and when they were used. This concept is crucial for understanding cultural practices and social structures of past societies, as it allows archaeologists to infer connections between artifacts and the people who created and utilized them, helping to build a narrative of historical events and activities.
Contextual Seriation: Contextual seriation is a relative dating technique used in archaeology that organizes artifacts or features from different sites based on their similarities and differences in context. This method helps to establish a chronological sequence of cultural change by comparing the spatial relationships and associations of items found in different layers or locations, allowing archaeologists to infer the progression of styles or technologies over time.
Frequency seriation: Frequency seriation is a relative dating technique used in archaeology to arrange artifacts or sites in chronological order based on their frequency of occurrence over time. This method relies on the assumption that certain types of artifacts become more or less common in specific cultural periods, allowing archaeologists to identify trends and patterns that indicate changes in human behavior and technological advancements. By plotting these frequencies, researchers can visualize how artifact styles evolve and establish a timeline of cultural change.
Typology: Typology is the systematic classification of artifacts or features based on shared characteristics, allowing archaeologists to organize and analyze material culture. This classification helps in understanding cultural and chronological contexts, as it can reveal patterns of behavior, technological development, and social organization within past societies.
Seriation: Seriation is a relative dating technique that organizes artifacts or other archaeological finds in a chronological sequence based on their characteristics, such as style or frequency. This method allows archaeologists to understand cultural changes over time and establish relative timelines by comparing the changes in artifact types and styles within a specific context.
Horizontal excavation: Horizontal excavation is a method used in archaeology that involves digging a site in a horizontal plane to uncover artifacts and features spread across a wide area, rather than focusing on depth. This approach allows archaeologists to understand the layout of a site and how different layers and artifacts relate to each other spatially. By employing this technique, researchers can effectively map out the relationships between various elements at a site, contributing significantly to understanding the historical context of the findings.
Vertical excavation: Vertical excavation is a method used in archaeology that involves digging straight down into the ground to uncover layers of soil and artifacts in a specific area. This technique is essential for understanding the stratigraphy of a site, revealing how different layers correspond to various time periods and cultural practices. It provides archaeologists with a clear view of the chronological sequence of human activity at the site, allowing them to analyze changes over time.
Stratigraphy: Stratigraphy is the study of rock layers (strata) and layering (stratification), which is essential in understanding the chronological sequence of archaeological deposits. By examining the arrangement and distribution of layers, archaeologists can establish a timeline for human activity, uncover cultural practices, and understand environmental changes over time.