In Current World Archaeology 89 (June 2018) – www.world-archaeology.com … there is an article on Iran's prehistory. It says the archaeology of Iran is dominated by the Zagros mountain chain which divides it from the flood plain of the Tigris and Euphrates. To the west of the Zagros are the fertile lands of Mesopotamia and to the east the hilly upland of the Iranian plateau (rich in metals but also fertile in places). The Neolithic revolution, we are informed, began in the hills and valleys of the Zagros between 10,000 and 8,000BC. This is where wild ancestors of sheep and goats are thought to have roamed – and grain cultivation. It then says that around 6,000BC the Neolithic revolution spread westwards (to found Ur and Uruk in Sumeria) and eastwards to the plateau region (the article focussing on Sialk). The 6th millennium archaeology of the Iranian plateau are mostly restricted to 900 to 1200m above sea level – and Sialk fits into this bracket. Sialk was founded around 6000BC – a date which follows closely behind the 6200BC event (which witnessed abrupt global sea level changes). It seems that this event (involving climate change also) that caused people to colonise Iran and Iraq but also, at the same point in time another group of Neolithic people (in Anatolia and the Levant) migrated into the Balkans and eastern Europe. At Sialk the first farmers grew wheat and barley and herded cattle, sheep, goats and pigs.
The next big upheaval was associated with the beginning of the Bronze Age. Presumably this is around 3000BC and coincides with another phase fo climate change and societal upheaval . In fact, the author claims there was significant disruption across the length and breadth of Iran characterised by a wholesale abandonment of rural settlements. Houses of Sialk level III were destroyed by fire and succeeded by a new lay out. As is their want archaeologists interpreted this as an invasion from the south rather than stringing together evidence of a massive natural disaster (which would have included earthquakes). The author claims this was roughly contemporary with Jemdet Nasr in Sumeria. This site is famous for the appearance of horse riding incomers from the central Asian steppes.
Again, at the end of the LB age (the mid to late 3rd millennium event is not mentioned) further disruption across Iran occurred – which is also true of Sialk. This is when the arrival of Indo-Iranian tribes is thought to have occurred – at the beginning of the Iron Age. Later, in the middle of the first millennium BC Sialk was abandoned – at the beginning of the Achaeomenid Persian empire (Cyrus and Darius and Xerxes etc). The nearby town of Kashan replace Sialk it would seem and it is thought to contain evidence of Achaemenid, Parthian and Sassanian period settlement (but the archaeology has not been done).