Contamination

Definition

Contamination refers to the unwanted introduction of foreign materials or substances into a sample, which can compromise the integrity of scientific analyses and interpretations. In dating methods like radiocarbon and thermoluminescence, contamination can lead to inaccurate results, as the presence of modern carbon or light exposure can skew age estimates, making it crucial for archaeologists to minimize its impact during sample collection and processing.

5 Must Know Facts For Your Next Test

1. Contamination can occur from various sources, including handling by researchers, exposure to modern materials, or environmental factors like soil and water.
2. In radiocarbon dating, contamination from modern carbon can significantly alter age results, making it appear that a sample is younger than its actual age.
3. For thermoluminescence dating, exposure to light after a sample has been buried can reset the accumulated radiation dose, leading to misleading age determinations.
4. To reduce contamination risks, archaeologists often follow strict protocols during excavation and sampling, including wearing gloves and using clean tools.
5. Identifying potential contamination sources is essential for interpreting dating results accurately; a thorough understanding of the context helps in evaluating the reliability of age estimates.

Review Questions

• How does contamination specifically affect the accuracy of radiocarbon dating results?
  • Contamination affects radiocarbon dating by introducing modern carbon into a sample, which can make it seem younger than it truly is. For instance, if a researcher touches an organic artifact with bare hands, oils and residues from skin can be absorbed, leading to an erroneous measurement of carbon-14 levels. Therefore, it's crucial to handle samples carefully and follow established protocols to mitigate these risks.
• Discuss the measures archaeologists take to prevent contamination in thermoluminescence dating and their importance.
  • To prevent contamination in thermoluminescence dating, archaeologists must avoid exposing samples to light after they have been buried. This is because light can reset the luminescence signal and lead to inaccurate age estimates. Additionally, researchers often use specially designed containers and gloves when handling samples to minimize any external light or particulate interference. These measures are vital for ensuring the reliability of the dating results.
• Evaluate the broader implications of contamination on archaeological interpretations and how they shape our understanding of ancient societies.
  • Contamination can have significant implications for archaeological interpretations as it may lead to incorrect dating of artifacts or features, affecting our understanding of ancient societies' timelines and cultural developments. If contaminated samples suggest an earlier or later date than accurate, it could misrepresent historical events or technological advancements. Therefore, recognizing and addressing contamination not only improves data accuracy but also enhances our overall understanding of human history and prehistoric contexts.

Related terms

Radiocarbon Dating:

A method used to determine the age of organic materials by measuring the decay of carbon-14 isotopes.

Thermoluminescence: A dating technique that measures the accumulated radiation dose in materials like pottery, indicating the last time they were heated.

Sample Preservation: Methods and techniques used to maintain the integrity of archaeological samples to prevent contamination before analysis.