The Stob Earth Pyramids ( bg, Стобски пирамиди) are rock formations, known as

hoodoos A hoodoo (also called a tent rock, fairy chimney, or earth pyramid) is a tall, thin spire of rock formed by erosion. Hoodoos typically consist of relatively soft rock topped by harder, less easily eroded stone that protects each column from th ...

, situated at the foothills of the

Rila Rila ( bg, Рила, ) is the highest mountain range of Bulgaria, the Balkan Peninsula and Southeast Europe. It is situated in southwestern Bulgaria and forms part of the Rila– Rhodope Massif. The highest summit is Musala at an elevation of 2, ...

mountain range in south-western

Bulgaria Bulgaria (; bg, България, Bǎlgariya), officially the Republic of Bulgaria,, ) is a country in Southeast Europe. It is situated on the eastern flank of the Balkans, and is bordered by Romania to the north, Serbia and North Mac ...

. They span an area of 0.7 km² near the village of Stob,

Kyustendil Province Kyustendil Province ( bg, Област Кюстендил, trl ''Oblast Kyustendil'') is a province in southwestern Bulgaria, extending over an area of (constituting 2.7% of the total territory of the Republic of Bulgaria), and with a populat ...

. The rock formations are up to 12 m high and up to 40 m thick at the base. Their shape is mostly conical to mushroomlike. Some of the columns are topped by flat stones.

Location

The Stob Earth Pyramids are located at the western foothills of the

mountain range in the

Balkan Peninsula The Balkans ( ), also known as the Balkan Peninsula, is a geographical area in southeastern Europe with various geographical and historical definitions. The region takes its name from the Balkan Mountains that stretch throughout the whol ...

at an altitude between 600 and 750 m. They occupy the Klisura ridge facing the valley of the

Rilska River The Rilska River ( bg, Рилска река, ''Rilska reka'', "Rila River") is a river in south-western Bulgaria, a left tributary of the Struma. The river is 51 km long and drains the western sections of the Rila mountain range. Geograp ...

, a left tributary of the Struma. They are situated at less that one kilometre east of the village of Stob in

Kocherinovo Municipality Kocherinovo Municipality is a municipality in Kyustendil Province, Bulgaria Bulgaria (; bg, България, Bǎlgariya), officially the Republic of Bulgaria,, ) is a country in Southeast Europe. It is situated on the eastern flank of ...

. They lie some 83 km south of the national capital

Sofia Sofia ( ; bg, София, Sofiya, ) is the Capital city, capital and List of cities and towns in Bulgaria, largest city of Bulgaria. It is situated in the Sofia Valley at the foot of the Vitosha mountain in the western parts of the country. ...

and 18 km north of the city of

Blagoevgrad Blagoevgrad ( bg, Благоевград ) is а town in Southwestern Bulgaria, the administrative centre of Blagoevgrad Municipality and of Blagoevgrad Province. With a population of almost inhabitants, it is the economic and cultural centr ...

Geology and formation

Geologically, the Stob Earth Pyramids are part of the Blagoevgrad

Graben In geology, a graben () is a depressed block of the crust of a planet or moon, bordered by parallel normal faults. Etymology ''Graben'' is a loan word from German, meaning 'ditch' or 'trench'. The word was first used in the geologic contex ...

that consists of lakebed, alluvial and sloping deposits dated from the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Pleistocene The Pleistocene ( , often referred to as the '' Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed ...

epochs. They are built up by

Precambrian The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of th ...

metamorphic rocks. There are two

geological formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock expo ...

s: the Dzherman Formation consists of aleurolite, clay and sandstone; the Barakovo one is built up by conglomerate and sandstone. During the Pliocene the area was at the bottom of a shallow lake and accumulated sediments that form a 200 and 250 m thick stratum consisting of little fragments with a lot of clay. The colour is dull white to yellowing. It forms the foundations of the pyramids but the erosion reveals only small patches this layer. The Pleistocene stratum above is reddish with alternating layers of cobble conglomerate and lightly soldered sandstone, as well as larger rock pieces originating from the slopes of Rila. The principal factor for the formation of the Stob Earth Pyramids is erosion due to rainfall. The rain drops penetrate the lightly soldered sediment and continuously wash it away. The location of the rock pieces in the stratum determines the place, size and shape of each pyramid because they prevent the abrasion of the layers below. They are covered by a 1 cm thick coat of hardened sun burned clay which protects the fragile sandstone and delays the erosion.

Description

The Stob Earth Pyramids vary in shape from sharp through conical to mushroomlike. About half of the formations are crowned by rocks, whose area is sometimes two to three times larger than the cross-section of the pyramid below. Their height averages some 6 to 10 m but can reach up to 12 m; the thickness at the base is up to 40 m. Most of them are facing in southern direction but there are also a few grouped together on the northern slopes of the ridge overlooking Stob. Groups of individual Pyramids have been named the Towers, the Brothers, the Hammers, the Wedding Couple, the Pinnacles, the Samodiva Chimneys, etc. They are tourist destination, although not as popular as the much larger

Melnik Earth Pyramids The Melnik Earth Pyramids ( bg, Мелнишки пирамиди) are rock formations, known as hoodoos, situated at the foothills of the Pirin mountain range in south-western Bulgaria. They span an area of 17 km2 near the town of Melnik, ...

. The rock formations are easily accessible via the

Struma motorway The Struma Motorway (, ) is a motorway currently under construction in Bulgaria. The motorway is located in the Yugozapaden area in South West Bulgaria, and follows the route Sofia- Pernik-Dupnitsa- Blagoevgrad- Sandanski to Kulata on the border ...

and the parallel first class I-1 road that form part of

European route E79 European, or Europeans, or Europeneans, may refer to: In general * ''European'', an adjective referring to something of, from, or related to Europe ** Ethnic groups in Europe ** Demographics of Europe ** European cuisine, the cuisines of Europe a ...

along the Struma valley. The third class III-107 branches from I-1 at the municipal centre

Kocherinovo Kocherinovo ( bg, Кочериново, ) is a town in southwestern Bulgaria, part of Kyustendil Province. It is the administrative centre of Kocherinovo Municipality, which lies in the southern part of Kyustendil Province. As of 2013 it has 2,25 ...

and heads for 7 km to north-east to Stob. The Stob Earth Pyramids were declared a natural landmark in 1964 with a total extension of the protected area of 7.4 hectares, or 0.74 km².

Citations

References

External links