The isotopic zones are a product of the Continental drift theory and its modern development, plate tectonics, which prevailed after 1958. The earliest ideas of the Hellenic orogeny are a product of the previous Geosyncline theory, in which the mountains of the Earth were believed to have been raised by compression of large depressions, of geosynclines, caused by shrinkage, and infilled with sediment. It was hypothesized that the mountains of Greece, called the Hellenides, arose from a Hellenic geosyncline in two phases, a volcanic breakthrough in the center, resulting in the “inner Hellenides,” and a subsequent orogeny at the west periphery from the wrinkling of sediment running off the central mountains. The peripheral range was the “outer Hellenides.” As both theories featured a compressional regime, the Hellenides terminology was kept, but it had to be matched to the isopic zones   .
The isotopic zones are a product of the Continental drift theory and its modern development, plate tectonics, which prevailed after 1958. The earliest ideas of the Hellenic orogeny are a product of the previous Geosyncline theory, in which the mountains of the Earth were believed to have been raised by compression of large depressions, or geosynclines, caused by shrinkage, and infilled with sediment. It was hypothesized that the mountains of Greece, called the Hellenides, arose from a Hellenic geosyncline in two phases, a volcanic breakthrough in the center, resulting in the “inner Hellenides,” and a subsequent orogeny at the west periphery from the wrinkling of sediment running off the central mountains. The peripheral range was the “outer Hellenides.” As both theories featured a compressional regime, the Hellenides terminology was kept, but it had to be matched to the isopic zones . The Alpheios falls within river zone 3, the Outer Hellenides, an arc-like range continuing the Dinarides of the Balkans into western Greece, comprising most of the Peloponnesus, and including the southernmost arc of Aegean islands, with Crete, around to the coast of Anatolia (Hellenic arc). The isopic zones included, west to east, are The Ionian, the Tripolitsa, the Pindos, and the Parnassos. To the east are the inner Hellenides, partly volcanic, with the dividing line down the center of Greece. They end at the Chalcidic Peninsula, beyond which are the Rhodope and Serbomacedonian massifs .
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The Alpheios falls within river zone 3, the Outer Hellenides, an arc-like range continuing the Dinarides of the Balkans into western Greece, comprising most of the Peloponnesus, and including the southernmost arc of Aegean islands, with Crete, around to the coast of Anatolia (Hellenic arc). The isopic zones included, west to east, are The Ionian, the Tripolitsa, the Pindos, and the Parnassos. To the east are the inner Hellenides, partly volcanic, with the dividing line down the center of Greece. They end at the Chalcidic Peninsula, beyond which are the Rhodope and Serbomacedonian massifs