Show Details

Archaeological Digs

March 10, 2008

A listener asks: When archaeologists uncover ancient cities, why do they have to dig so deep?

Transcript

BOB HIRSHON (host):
Archaeology’s hidden layers. I’m Bob Hirshon and this is Science Update.

David Schwan of Fremont California wrote with this question: When archaeologists uncover ancient cities, why do they have to dig so deep? For the answer, we turned to archaeologist Kathryn Bard of Boston University.

KATHRYN BARD (Boston University):
Often, they are digging through centuries of buildup of houses and other structures. And so, frequently, when a house collapses for one reason or another, then another house is built on top of it; the same is true of ancient temples, so this accumulates a lot of deposits over centuries. And if you want to go to the early part of the site, you have to dig down through much later parts.

HIRSHON:
And natural processes such as decomposition, plant growth, and weather can all contribute to the decay of earlier structures and the layering of archaeological sites. If you have a science question, call us at 1-800-why-isit. I’m Bob Hirshon, for AAAS, the science society.