From an analysis of broken pottery and statuary, archaeologists have estimated that an ancient settlement in southwestern Arabia was established around 1000 B.C. However, new evidence suggests that the settlement is considerably older: tests show that a piece of building timber recently uncovered at the site is substantially older than the pottery and statuary.
Conclusion
New evidence suggests that the settlement in SW Arabia is considerably older than 1000 B.C.
Evidence (colon)
Tests show that a piece of building timber recently uncovered at the site is substantially older than the pottery and statuary.
Evaluate
When they look at the pottery / statues, the age of the materials makes them think this settlement started in 1000 B.C., but our author is saying that if you look at the timber (the wood), those materials make the site seem way older than that.
Given that ... the wood used in the building seems a lot older than the pottery / statuary used, How could we say that ... the settlement wasn't established until 1000 B.C.?
Does the age of the timber wood used reliably tell us when a settlement was established? Isn't it possible that you move into an area in 1000 B.C. and use wood that was chopped down in 1500 B.C.?
The evidence also tells us that this is just a piece of wood. Could it be a random scrap of wood that wasn't really part of the settlement? Maybe going off the pottery is a more reliable / robust way of dating the site.
Goal
Let's look for a way to argue that,