Thursday, February 14, 2008

Feb. 14: Dating the Past

Feb. 14: Dating the Past
Reading for Today: Ashmore and Sharer, "Dating the Past," pp. 157-178.

Dating the Past





This is a great video about radiocarbon dating, also known as carbon-14 dating! This is the most generally useful method of absolute dating used in archaeology.

The most important things to remember about dating archaeological data:

1. Every method has its applicability/limitations to certain situations, materials, and ages.
2. The more you can cross-check dates through different methods, the more reliable the dates.
3. Your dates are only as good as your data, the way they were collected, etc.
4. You generally will not do the dating yourself, only the sampling; data is sent to laboratories and specialists, and can be expensive.
5. Dating materials is not an end in itself; dating is only significant in terms of the research questions you are asking.

TOPICS DISCUSSED IN CLASS (Read the Chapter for details):

Direct dating- analysis of the artifact, ecofact, or feature itself to find its age
vs
Indirect dating- analysis of the material associated with the artifact/ecofact/feature to find the age (ex: the matrix around the artifact)

Relative dating- evaluating the age of one artifact/ecofact/feature relative to another (which is older than the other)
vs
Absolute dating- placing the age of the artifact/ecofact/feature on an absolute time scale (such as 4000 B.C. or A.D. 1970)…most are expressed in a range (the plus-minus symbol, or as "ca."= circa)

SERIATION
Seriation
Stylistic seriation
Frequency seriation - battleship-shaped curves

SEQUENCE COMPARISON
Sequence comparison aka cross-dating

STRATIGRAPHY
Stratigraphy

GEOCHRONOLOGY
Geochronology
Horizontal stratigraphy

OBSIDIAN HYDRATION
Obsidian hydration

FLORAL AND FAUNAL METHODS
Dendrochronology
Bone chemistry

RADIOMETRIC METHODS
Radiometric
Half-life
Radiocarbon dating (carbon-14)
Potassium-argon dating
Argon-argon dating
Uranium-series dating
Fission-track dating

ARCHAEOMAGNETISM
Archaeomagnetism

LIMITED AND EXPERIMENTAL METHODS
=========

Genographic Project



In today's class, we also watched a portion of the DVD about the National Geographic Society's "Genographic Project."



DNA studies such as the Genographic Project have been used to supplement and cross-check the archaeological record, and the spread of humankind across the globe.

Next class's reading assignment (Tuesday, Feb. 19) is Ashmore and Sharer, Chapter 8: “Reconstructing the Past,” Pp. 179-211.

2 comments:

Ryan said...

Hi Lance,
I'd just like to give you a courtesy notice to let you know that I'll be absent from class Tuesday, February 19th.
I respect your time and ordinarily wouldn't miss the class; however, my girlfriend is currently visiting from Scottsdale and I'd like to spend the day with her. I'll be in class Thursday, as normal.

Thank you for your understanding.

P.s. I tried to email you at yahoo without success.?

Sincerely,
Ryan N. d'Esterre

Lance Michael Foster said...

My email at Yahoo is lancemfoster@yahoo.com