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F - 270 : The End of History - How Plate Tectonics Killed the Business of Ancient Ports

Updated: Nov 19, 2021

Ever wondered why ancient ports such as Marseille, Naples and Constantinople survived and others like Miletus, Knidos, Kaunas, Ephesus and Troy disappeared from history and left - at best - some ruins behind?

As a young boy, the story of Troy and how the German hobby archeologist Schliemann found it, fascinated me. The part I never understood was how Troy could be so far inland when Homer described how the Greeks harboured nearby and often went back to their ships. How does this reconcile with current geography?

Mighty walls like in Troy VI were only built when there was something valuable to protect!

The answer to my question lies in plate tectonics which we discovered as shaper and mover of Mediterranean history before - as for instance in the creation of the fertile coastal plains of Calabria which attracted Greek settlers around 800 BC and led to Magna Graecia.

Plate tectonics are at the heart of the emergence of Anatolia as land mass. As the African Continental Plate pushes north, it collides with the Europan Plate. In some places, this leads to subduction zones, in other places the former floor of the Tethys Sea folds and is pushed upwards, forming new land like the Alps, the Apennine or the Dalmatian mountains.

Subduction Zones and Plate Movemements in Anatolia

In Anatolia, the collision of Africa with Europe folds the Tethys Sea Floor mostly from south to north (with a few notable exceptions) and creates mountain ridges and valley systems on an east to west axis. This is most prominently visible on the Aegean side. Many of the resulting large valleys flooded at the end of the last ice age when sea levels rose by 100 m.

The faults and ridges of Anatolia which mostly follow an east-western direction

Once sea levels rose, these deep, Fjord like valleys started filling with sediments from Anatolia's mountains. The weather pattern in Turkey with dry summers, wet autumns and icy winters erode the Anatolian mountains by 1 - 2 millimetres per year, producing a giant amount of rubble and sediments which are carried downstream by violent rivers. The speed of the sedimentation was so fast that it was recorded in history. Already the Greeks and Romans struggled with it. The valleys of the Gediz River (north of Izmir) and the Büyük Menderes River (south of Izmir) are prominent examples and illustrate the case well.

Satelite Photo from Google Earth - Gezir Valley north, Büyük Menderes Valley south of Izmir

If unchecked, the Gezir River would close the access to the Port of Izmir, one of Turkey's main ports for exporting manufacturing goods, within a few hundred years. The diversion of river waters for irrigation slowed the sedimentation process down though. Also, now that the river deltas reach the open sea, they are exposed to sea currents which carry the lighter sediments away and reduce delta growth. The ancient town of Miletus, however, did not benefit from this. By late Antiquity, it was cut off from the Aegean and seized to be a port.

The shorelines around Miletus and Prieme during Antiquity. Today, the ruins of Miletus are at a distance of 10 km from the Mediterranean. It is almost inconceivable that Miletus was once the parent town to dozens of Greek colonies in the Black Sea and an important center of grain trading.

In front lies the sedimented harbour of Miletus where the Romans erected the Great Harbour Monument to honour General Pompey who defeated the Cilician pirates in Alanya, where we passed through in 2018. The photo was taken from the back of Miletus' Greek theatre.

The theatre in Miletus could sit 15 - 18'000 people which indicates that the town had a size of 250'000 - 300'000 citizens.

The most prominent Ancient Greek Harbour lost to sedimentation was probably Ephesus - one of the Mediterranean's main commercial centres. The town was so important that the Romans dug a long canal to keep it connected to the Mediterranean. Ephesus still had access to the Aegean Sea during the reign of Emperor Justinian who built important religious buildings here. Mother Marie lived in Ephesus at the end of her life. Today, Ephesus is now at a distance of 5 km from the sea.

The well known library in Ephesus - luckily there are fewer tourists in October!

The progress of sedimentation over the centuries - in the end, even the artificial harbour did not help. When the Seljuk Turks conquered Ephesus in the 11th century, it had shrunk to the size of a small village and had lost its access to the sea several centuries earlier.

City map of Roman Ephesus with town walls, the main buildings and the artificial port with its canal to the Aegean Sea. The library is no 8 on the map

The well preserved road leading to Ephesus' artificial port

With today's giant mechanical diggers, the problem of sedimentation can be solved. In Antiquity and the Middle Ages, sedimentation of a port was often the dead knell to its existence. Whilst harbours away from large rivers like Constantinople, Marseille or Naples continue to exist, others disappeared once cut off from the sea.

This leads me to an interesting thought about the Trojan war. Had the Greek Army waited long enough - maybe a few hundred years - alluvial sedimentation would have eliminated Troy's powerful position on the Dardanelles from where it controlled the sea lanes to the Black Sea with its trade in wheat and slaves. But we know from Homer that the Greek Army wanted to go home after 10 years of siege.

The eventual sedimentation of Troy's harbour a few centuries after the epic siege

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