How many years passed between settlements in northern and southern Mesopotamia?

Settlements in southern Mesopotamia, particularly in the region of Sumer, emerged around 4500 BCE, while significant settlements in northern Mesopotamia, such as those in the region of Assyria, began to develop around 3500 BCE. This indicates that approximately 1,000 years passed between the establishment of settlements in southern Mesopotamia and those in northern Mesopotamia.