Franchthi cave or Frankhthi cave is an archaeological site overlooking Kiladha Bay, in the Argolic Gulf, opposite the village of Kiladha in southeastern Argolis, Greece

Between Ερμιονίδα (Ermionida) and Κοιλάδα (Kilada) at the coast. Follow the road from Ligourio to Port Cheli. A few hundred meter after the town Fourni there is a turnoff to the right to Παραλία Φούρνων (Paralia Fournon). Follow this road straight to the west to the beach. Park car and walk to the left, at the end of the beach a trail starts which leads south to the cave. Its about 1km walk.

Phránchthi Cave:

Although the cave is most known for it's Archeological history and discovered settlements far back in time, the cave has some interesting Geological elements too.

Franchti is on a rocky headland just above the shore of the bay, a small embayments on the south-east coast of the gulf of Argos in the Peloponnesian. Its wide mouth open towards the north-west. During the periods of occupation represented in the cave by the bay of Kilhada was dry land and the coast line of the gulf of Argos was as much as 5km distant because of lower sea levels during the last glacial period. Thus a wide coastal plain lay in front of the cave throughout much of its history.

The cave is about 30m wide and about 5m high at the entrance but expands to near 45m wide in the middle. The present cave floor is about 12m above sea level, but the cave sediments fill extends well below present sea level. Two large 'windows* open to the sky where the overlying bedrock has collapsed into the cave, leaving large piles of enormous limestone blocks on the cave floor. The major collapse appears to have occurred at or near the end of the Neolithic period and proably covers archeological deposits that are currently unreachable. The colapses have left only one area of floor habitate and more or less level. It is just inside the entrance and measures about 35x38m. This is the area where the excavations took place.

Archeological data prove that the rockfall here belong chronologgically to a period before and during the Neolithic (about 7,000-3,000 years B.C.). Near the bottom of the pond located at the rear of the cave, potsherds and other artefacts of final Neolithic to early Byzantine times (about 4,500 years B.C. to the 6th century A.D.) have been found. This part of the cave may have been in regular use during the Paleolithic until the early Neolithic period (at least from 40,000 years to the 8th millennium B.C.), given that it was presumably a dry cavity, when sea level was much lower than today.

The present view and extent of the cave is not the same as that during its prehistoric occupation. The further we go in time, the lower the floor was and consequently, more spacious the chamber were.
Over time, various materials have been deposited on the cave floor, resulting in its gradual rise. Some of these were of natural origin, such as rocks from the walls and roof, dust blown in by the wind or clay transported by water percolation through the roof. All of these contributed to the formation of geological layers.
In addition, archeological material such as the remains of meals, tools, ash from heats, constructions debris and refuse were incorporated within the layers.

In order to study the evolution of the cave and the history of its use by humans, archeologists excavated deep vertical trenches. In this way the layers appear in section and can be "read" in chronological order, from the oldest at the bottom, to the youngest at the top.
The trench H-H1 reached a maximum depth of 9,71m, revealing a succession of layers from the upper Paleolithic to the end of the Neolithic.

A volcano marks the early history of the cave.

Approximately 40,000 years ago, an enormous volcanic eruption occured at Campi Flegrei in southern Italy, with ash spread over a major part of Europe and at the Eastern Mediterranean. At Franchthi , this formed a thick layer at approximately 10m below the current ground surface. Precise dating of tephra particles within the ash, points to early human occupation of the cave prior to the eruption, probably during the Middle Palaeolithic. Volcanic tephra of the same origin has been detected at other Greek sites, including nearby Klissoura Rockshelter, also in the Argolid.

In the illustration, the northern face of the Trench is shown with its main chronological subdivisions. Particular archeological layers are numbered, each chronological subdivisions is linked to key technological and subsistence markers, witch are characteristic of each period.

Stalagctites:

If you look up just after entering the cave you will see a lot of Stalactites.

When water seeps into the cave and drips from the ceiling, a stalactite is the result. The first stage is a hollow soda straw stalactite. The water drop travels down the central canal of the soda straw and hangs on the end, depositing more calcite (calcium carbonate) before dropping to the floor. When the hollow tube eventually plugs up, more water runs on the outside of the stalactite, making it thicker and forming a stalactite. Yet there is still some water moving internally through stalactites (hence the helictites that form on some and the recrystallization of the internal portions). If the drop of water that falls still contains calcite when it hits the ground, this may deposit as well to form a stalagmite. They tend to be squatter than stalactites. The longer the water drop hangs from the ceiling, the less likely it is to still contain calcite when it lands on the floor. Not all stalactites have stalagmites beneath them. Columns result when a stalactite and stalagmite join.

Hollow stalagmites:

These are rare, in the Sorbas Gypsum Karst there are and it seems not to have been described anywhere else. Their formation is based on the simultaneous precipitation and dissolution of gypsum, but with the peculiarity that their origin is linked to stalactites made of calcite.

Examination of these stalagmites shows that a central orifice runs from apex to base. How can the hole and the stalagmite be formed at the same time? The answer in not so complex at all: precipitation of calcite on the stalactites means that the water that seeps in through the ceiling and creates the stalactites remains subsaturated in gypsum, so the continuous central orifice in the stalagmite is maintained: a veritable mineralogical jewel of nature I would say!

Source: Local information board and Archives of Ephorate of Palaeoanthropology and Speleology, S.G. and Indiana University (U.S.A).

Tasks to do and to mail me for approval, once you have mailed me the answers you can log online:

1 - Campi Flegrei had an eruption that formed a thick layer of ash in the cave approx 10m down below current ground face, in what time period did it occur?

2 - What particle in the ash gave us precise dating of the eruption?

3 - What is the thickness of the second layer and what age does it belong to?

4 - In the roof of the cave we see different kinds of Stalactites, can you see any Stalagmites?

Logs without these requests fulfilled may be deleted!