Diagnostics, Stratification and Zeppelin

Just a bit of a restatement or expansion of Mike's question and my response from class today.

The survey project I described used diagnostic pottery and projectile points to place the sites in the region into a basic temporal sequence.  What inferences was this based on?  Well, bear with my analogy again...

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It relied on the fact that archaeological work had been done in neighboring areas where a more definitive sequential relationship could be determined.  Imagine that Phoenix was filled with sites that people lived in for hundreds and hundreds of years.  They continually dumped garbage in the same spot over that time.  This constant behavior would lead to the development of distinct layers of cultural material from bottom to top, with the lower material being older and the upper being younger.  The Led Zeppelin albums are at the bottom, Bon Jovi in the middle and the Nirvana albums are at the top.  This situation would be what archaeologists would call a well stratified site.

In Tucson, however, people didn't stay in the same sites for long, maybe 50 years at a time.  This means that the same kind of patterns of stratification couldn't develop.  However, the folks here still liked them their pop-rock music.  That means that you still find Zeppelin, Bon Jovi and Nirvana at different sites.  Because of their similarities to the material in Phoenix, we can assume they were likely in use in Tucson at the same time as they were in Phoenix.  This allows us to make inferences about the dating, at least the sequence, of the sites in Tucson.