THE RECORD
What changed
Hammering native copper expanded into ore smelting and casting, while canals and embankments distributed water in dry regions.
EVIDENCE
What remains
Slag, crucibles and mines document high-temperature production; canal sediments and landscapes document long-term water management.
WHY IT MATTERS
Why it matters
Specialized knowledge, resource exchange and collective maintenance deepened interdependence among settlements.
OPEN QUESTION
Where interpretation begins
Metal and irrigation did not automatically create states or classes; small communities also managed complex systems.