Dating Lab EXAM

• The time range perceived by human beings is related to:

  • Astronomical cycles related to day/night
  • Astronomical cycles related to annual season (summer/winter)
  • Our individual memories
• Concerning dating methods:

  • Some of the dating methods used in geology can also be applied to archaeological and paleoanthropological problems
  • Several methods can be applied to very extended time ranges (that is 104-1015 seconds)
  • Each method has a definite time range application
• Radiocarbon dating can be applied to a time range of:

  10^3-10^4 to 10^5 years
• In any experimental measurement (including dating), accuracy is related to:

  How close is the measurement to the "true value" in terms of the adopted standard used for calibration.
• Concerning stratigraphic sequences:

  • In stratigraphic sequences encompassing anthropogenic activity, inverse or reverse stratigraphies may sometimes be recognized on the basis of radiocarbon dating.
  • In stratigraphic sequences encompassing anthropogenic activity, inverse or reverse stratigraphies may sometimes be recognized on the basis of archaeological evidence.
• The following reaction rates can be used for relative dating:

  • The L-form to R-form conversion in amino acids
  • The fluorine content of teeth apatite
  • Uranium content in bones
  • Hydrogen content of volcanic glass
• In archaeomagnetic dating:

  Several samples should be collected, and they must be well oriented in terms of the present day magnetic field of the Earth
• Paleomagnetic dating:

  Relies on the continuous polar wandering of Earth’s magnetic pole
• Dating methods based on radioactive decay:

  Exploit the natural instability and the radioactive decay of specific elements

  Include parent-daughter systems that change their decay constant in time
• Thermo luminescence dating (TL):

  • Is based on the slow accumulation of electron traps in solids
  • Can be applied only to materials that were never heated above 1000°c
  • Measures only the accumulated electron traps in materials due to external radiation (cosmic rays)
  • It measures the time since the last heating of the material
• What is time?


  Continued sequence of existence and events that occurs in succession from past, present and into the future. Also referred as a component quantity of various measurements used to sequence events, compare duration or intervals of them, and, to quantify rates of changes.
• Concerning the time-frame of appearance of man on Earth:

  • Homo sapiens appeared between 0.1 and 0.3 ma yrs ago
  • Homo erectus appeared between 1 and 2 ma yrs ago
  • Australopithecus lived before 1.0 ma yrs ago
• Chemical stratigraphy:

  • Requires a systematic and well-documented chemical analysis of well-dated representative materials.
  • Requires a large number and well-documented chemical analysis of representative materials of the same site.
• Dendrochronology:

  • Requires a continuous calibration curve from present time
  • Exploits the variation in thickness of tree-rings due to seasonal variations
  • Exploits the variation in thickness of tree-rings due to local geographic climatic conditions
• Optically stimulated luminescence dating (OSL):

  • Requires taking samples in full dark conditions
  • Records the accumulated electron traps in materials due to light irradiation of the surface
  • Measures the time since the last heating of the material