6S, the longest salt cave in the world

summary 

Covering an area of approximately 1.7 km2 of the upper part of a block of salt, there is a complex karst and well developed. Were found 50 cavities. The most important is Pestera 6S de la Manzalesti, with 3234 m development and -42 m depth. It is develops on three main levels, the inferior being crossed by water.

We present here the evolution of the cave, they made references to paleontological and paleobotanical aspects. A comparison between the salt caves and limestone caves also exists. We propose a classification of speleothems in the manner in which water contributes to their genesis.

1 Location 

In north-west of the city Buzau, in the basin of Valee Jghiab tributary of Slanic, on the Plateau Meledic (600 m altitude).

All Meledic Plateau, including slopes, is covered with a rich and varied exokarst: lapies fields, dolines, ouvales, ponors, canyons, steps antitetiques and others.

Teams Caving Club "Emil Racovita" Bucuresti have discovered more than 50 fully formed cavities in salt or on salt and breaches contact; total development 4544 m, depth 354 m. All cavities have permanently or temporarily water.

2 Geology 

Plateau Meledic is modeled on the salt deposit Lopatari with 3.4 km2 surface and an inclination of 60o. According to the structural position of the solid salt, age has been assessed as Aquitanian. The average content of the deposit is 81.7% NaCl.

Clays and breaches of its upper part have thicknesses up to 40 meters but there are also relatively large areas where salt is at the surface.

3 Exploration 

Pestera (the cave) 6S de la Manzalesti was discovered September 13, 1980 by Ica Giurgiu and Gabriel Silvasanu. Topographies were 1257 m development (-32 m depth) until October 25, 1980, when the entrance of the cave was found pluged up. This length represented a new world record for the salt caves. In the cavity we were able to penetrate new sentence in October 1985, another place. Until March 1986 it was still surveying the cave, reaching 3190 m and 42 (-40, +2) m depth, 284 m extension and ramification index of 11.23.

In June 1992 we entered the cave 6S by a third input, setting the length to 3234 m and the depth to -42 m.

The synthesis of topographic data from inside was conducted by Ica Giurgiu and Gabriel Silvasanu. The topographic data from outside have been synthesized by Ica Giurgiu.

4 The evolution of cave 

After the formation pressure of the first galleries, subaerial drainages (among the Mare Lake and Meledic Creek, respectively among the back slope antitetique C and Meledic Creek) have been gradually transferred to depth in modeling vadose regime and amplifying the network of galleries.

Now, the cave is developed on three main levels superimposed that is less have water, the higher have important caving in. The branch southeast of the cave is covered by water collected in the back slope antitetique C.

5 Comparison with caves developed in limestone 

There are many similarities: forms digging pressure on the ceiling and walls, ceilings horizontal plane, levels of erosion, meanders, terraces of rock, canyons deepening, sediments.

Differences. The salt speleothems have shapes much more different; their color is much richer and can change several times along speleothem. Because microclimate saline, the remains of plants and wildlife that are fixed in or on sediments remain exceptionally.

6 The sediments 

In general, the sediments are allochthonous, with elements from very thin to thick, very well rounded. In sediments there is a lot of plant remains (plants and trees), diverse and various dimensions, many very well preserved. There are a lot of sediment in general and their thickness is important.

7 Paleontology 

In the area called The Library (Biblioteca), a mid-level terrace has been discovered by author a teeth of herbivore, determined by the archaeologist Alexandra Bolomei from History Museum of Romania as an upper molar of Eqvus hemionus (a species of small horse) with a seniority appreciated more than 12,000 years.

There is a rich deposit of remains of birds in the northern zone of the cave in the upper floor. There are also remains of birds in other areas of the cavity.

8 Climatology 

The meroclimat of stability have values between 8.5 and 12o Celsius.

9 Speleothems 

Abundant, diverse and with a color complex. We propose to them a clasification the manner in which water contributes to their genesis.

A. Speleothem drip

1. stalactites; forms:

- conical

- cylindrical

- bayonet

- one or more change of direction (it may exist on their bodies small threads sousmillimetriques in various forms, long up to 2 cm or forms attached with two-dimensional type flag)

- cell (the redissolution has created spa-ces in the body of stalactite)

- macrocrystals attached (shapes, sizes and various colors)

- small fir invers

- on roots

2. stalagmites; forms:

- cylindrical

- conical

- any

- influenced by the direction of air

- in the layer of alluvium

           - needles

           - grass

           - glass sewer

3. columns

B. Speleothems by gravitational ooze

1. parietal flowing; of:

- salt

- salt and other substances

2. floors

3. gours, microgours

C. Speleothems by capillary ooze

1. speleothems coral

- inlay

- antodites

- cauliflower

2. eccentrics

D. Speleothems in basin

1. macrocrystals

2. carpet of crystals.

The formations are white or different colored (stalactites, columns, parietal flowing, macrocrystals / shades of red, brown, rust, yellow, gray).

Were harvested for quantitative analysis of evidence. The 20 samples studied have identified a total content of substances non-halogenated (Fe2O3, MnO, CaSO4, CaCO3, MgCO3) between 0,089-46,082% and a total content of halogenated substances between 53,918-99,911%. For the first time facing the bibliography it is reported the presence of MnO.