Stone run
Encyclopedia
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...
of particular rock varieties caused by myriad freezing-thawing cycles taking place in periglacial
Periglacial
Periglacial is an adjective originally referring to places in the edges of glacial areas, but it has later been widely used in geomorphology to describe any place where geomorphic processes related to freezing of water occur...
conditions during the last Ice Age.
The actual formation of stone runs involved no less than five processes: weathering
Weathering
Weathering is the breaking down of rocks, soils and minerals as well as artificial materials through contact with the Earth's atmosphere, biota and waters...
, solifluction
Solifluction
In geology, solifluction, also known as soil fluction, is a type of mass wasting where waterlogged sediment moves slowly downslope, over impermeable material. It occurs in periglacial environments where melting during the warm season leads to water saturation in the thawed surface material ,...
, frost heaving
Frost heaving
Frost heaving results from ice forming beneath the surface of soil during freezing conditions in the atmosphere. The ice grows in the direction of heat loss , starting at the freezing front or boundary in the soil...
, frost sorting, and washing. The stone runs are essentially different from moraines, rock glacier
Rock glacier
Rock glaciers are distinctive geomorphological landforms of angular rock debris frozen in interstitial ice which may extend outward and downslope from talus cones, glaciers or terminal moraines of glaciers. There are two types of rock glaciers: periglacial glaciers, or talus-derived glaciers, and...
s, and rock flows or other rock phenomena involving the actual flow of rock blocks under stress that is sufficient to break down the cement or to cause crushing of the angularities and points of the boulders. By contrast, the stone run boulders are fixed quite stably, providing for safer climbing and crossing of the run.
Stone runs are accumulations of boulders with no finer material between them. In the Falklands, they occur on slopes of between 1 and 10 degrees, and are the product of mass-movement and stone sorting during past periods of cold climate. They everywhere occur in association with poorly-sorted, clay-rich solifluction deposits
Geographic distribution
Falkland Islands
The Falkland Islands are an archipelago in the South Atlantic Ocean, located about from the coast of mainland South America. The archipelago consists of East Falkland, West Falkland and 776 lesser islands. The capital, Stanley, is on East Falkland...
, and the stone rivers of Vitosha Mountain
Vitosha
Vitosha is a mountain massif, on the outskirts of Sofia, the capital of Bulgaria. Vitosha is one of the tourists symbols of Sofia and the closest site for hiking, alpinism and skiing. Convenient bus lines and rope ways render the mountain easily accessible. Vitosha has the outlines of an enormous...
, Bulgaria
Bulgaria
Bulgaria , officially the Republic of Bulgaria , is a parliamentary democracy within a unitary constitutional republic in Southeast Europe. The country borders Romania to the north, Serbia and Macedonia to the west, Greece and Turkey to the south, as well as the Black Sea to the east...
. The highly specific combination of particular climatic conditions and rock varieties that existed there during the Quaternary
Quaternary
The Quaternary Period is the most recent of the three periods of the Cenozoic Era in the geologic time scale of the ICS. It follows the Neogene Period, spanning 2.588 ± 0.005 million years ago to the present...
explains both the formation of stone runs in those two territories, and their absence in areas with otherwise comparable nature conditions.
For instance, while the present Falklands climate is quite similar to that of Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
the latter was completely glacial rather than periglacial during the relevant period, which would not allow for the formation of stone runs. On the other hand, due to geological and other specifics of the southern temperate
Temperate
In geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally relatively moderate, rather than extreme hot or cold...
and sub-Antarctic
Subantarctic
The Subantarctic is a region in the southern hemisphere, located immediately north of the Antarctic region. This translates roughly to a latitude of between 46° – 60° south of the Equator. The subantarctic region includes many islands in the southern parts of the Indian Ocean, Atlantic Ocean and...
territories with climatic history similar to that of the Falklands (Prince Edward Islands
Prince Edward Islands
The Prince Edward Islands are two small islands in the sub-antarctic Indian Ocean that are part of South Africa. The islands, named Marion Island and Prince Edward Island, are located at ....
, Crozet Islands
Crozet Islands
The Crozet Islands are a sub-antarctic archipelago of small islands in the southern Indian Ocean. They form one of the five administrative districts of the French Southern and Antarctic Lands.-Geography:...
, Kerguelen Islands
Kerguelen Islands
The Kerguelen Islands , also known as the Desolation Islands, are a group of islands in the southern Indian Ocean constituting the emerged part of the otherwise submerged Kerguelen Plateau. The islands, along with Adélie Land, the Crozet Islands and the Amsterdam and Saint Paul Islands are part of...
, Macquarie Island
Macquarie Island
Macquarie Island lies in the southwest corner of the Pacific Ocean, about half-way between New Zealand and Antarctica, at 54°30S, 158°57E. Politically, it has formed part of the Australian state of Tasmania since 1900 and became a Tasmanian State Reserve in 1978. In 1997 it became a world heritage...
, Campbell Islands, or nearby Tierra del Fuego
Tierra del Fuego
Tierra del Fuego is an archipelago off the southernmost tip of the South American mainland, across the Strait of Magellan. The archipelago consists of a main island Isla Grande de Tierra del Fuego divided between Chile and Argentina with an area of , and a group of smaller islands including Cape...
and Patagonia
Patagonia
Patagonia is a region located in Argentina and Chile, integrating the southernmost section of the Andes mountains to the southwest towards the Pacific ocean and from the east of the cordillera to the valleys it follows south through Colorado River towards Carmen de Patagones in the Atlantic Ocean...
), none of them features landforms even remotely comparable to the Falklands stone runs.
Likewise, the specific geology of Vitosha
Vitosha
Vitosha is a mountain massif, on the outskirts of Sofia, the capital of Bulgaria. Vitosha is one of the tourists symbols of Sofia and the closest site for hiking, alpinism and skiing. Convenient bus lines and rope ways render the mountain easily accessible. Vitosha has the outlines of an enormous...
accounts for the fairly restricted examples of similar landforms in other Bulgaria
Bulgaria
Bulgaria , officially the Republic of Bulgaria , is a parliamentary democracy within a unitary constitutional republic in Southeast Europe. The country borders Romania to the north, Serbia and Macedonia to the west, Greece and Turkey to the south, as well as the Black Sea to the east...
n or indeed Balkan
Balkans
The Balkans is a geopolitical and cultural region of southeastern Europe...
mountains with comparable climatic record among which Vitosha is one of the smallest, extending just 15 km (9.3 mi) by 10 km (6.2 mi). However, even on that small territory the stone runs exist along with scree
Scree
Scree, also called talus, is a term given to an accumulation of broken rock fragments at the base of crags, mountain cliffs, or valley shoulders. Landforms associated with these materials are sometimes called scree slopes or talus piles...
s and other rock landforms, suggesting that the right periglacial conditions and rock composition are necessary but not sufficient conditions for the formation of stone runs.
Other examples of stone runs occur in England, most notably at the Stiperstones, Shropshire. They are also known in Pennsylvania. Small examples are probably very widespread where solifluction deposits contain large concentrations of frost-resistant rock blocks.
Falklands stone runs
An early description of the Falklands stone runs was given in Antoine-Joseph PernetyAntoine-Joseph Pernety
Antoine-Joseph Pernety, known as Dom Pernety was a French writer. At various times he was a Benedictine, and librarian of Frederic the Great of Prussia...
’s account of his exploration of the islands during the 1763–64 French
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
expedition under Louis Antoine de Bougainville
Louis Antoine de Bougainville
Louis-Antoine, Comte de Bougainville was a French admiral and explorer. A contemporary of James Cook, he took part in the French and Indian War and the unsuccessful French attempt to defend Canada from Britain...
, which established the Port Saint Louis settlement on East Falkland
East Falkland
East Falkland the largest of the Falkland Islands in the South Atlantic, has an area of and a coastline long. Most of the population of the Falklands live in East Falkland, almost all of them living in the northern half of the island...
. While crossing the neck between Baye Accaron (Berkeley Sound
Berkeley Sound
Berkeley Sound is an inlet, or fjord in the north east of East Falkland in the Falkland Islands. The inlet was the site of the first attempts at colonisation of the islands, at Port Louis, by the French....
) and Baye Marville (Salvador Water
Salvador Water
Salvador Water or Port Salvador is a bay/inlet on the northeast coast of East Falkland, the largest of the Falkland Islands. It has an intricate shoreline, but could be described as being shaped like an "M"....
) he described in detail two particular stone features he called ‘City Gates’ and ‘Amphitheatre’:
Pernety’s observations were continued by young Charles Darwin
Charles Darwin
Charles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...
, who visited the Falklands in 1833 and 1834:
The Falklands stone runs are made up of hard quartzite blocks. They are more widespread and larger on East Falkland
East Falkland
East Falkland the largest of the Falkland Islands in the South Atlantic, has an area of and a coastline long. Most of the population of the Falklands live in East Falkland, almost all of them living in the northern half of the island...
, especially in the Wickham Heights
Wickham Heights
The Wickham Heights are a rugged chain of mountains on East Falkland in the Falkland Islands. They include the island group's highest peak, Mount Usborne, Mount Wickham and are partly contiguous with No Man's Land...
area where the largest of them extend over 5 km in length. Those on West Falkland
West Falkland
West Falkland is the second largest of the Falkland Islands in the South Atlantic. It is a hilly island, separated from East Falkland by Falkland Sound. Its area is and its coastline is long. Including the adjacent small islands the land area is .-Population:The island has fewer than 200...
and the minor islands are fewer in number and of smaller dimensions. Darwin's "great valley of fragments", subsequently renamed Princes Street Stone Run after Edinburgh
Edinburgh
Edinburgh is the capital city of Scotland, the second largest city in Scotland, and the eighth most populous in the United Kingdom. The City of Edinburgh Council governs one of Scotland's 32 local government council areas. The council area includes urban Edinburgh and a rural area...
's Princes Street
Princes Street
Princes Street is one of the major thoroughfares in central Edinburgh, Scotland, UK, and its main shopping street. It is the southernmost street of Edinburgh's New Town, stretching around 1 mile from Lothian Road in the west to Leith Street in the east. The street is mostly closed to private...
that was cobbled
Cobblestone
Cobblestones are stones that were frequently used in the pavement of early streets. "Cobblestone" is derived from the very old English word "cob", which had a wide range of meanings, one of which was "rounded lump" with overtones of large size...
at the time, occupies a 4 km long and 400 m wide shallow valley trending east-west. The feature is situated off the road to Port Louis
Port Louis, Falkland Islands
Port Louis is a settlement on northeastern East Falkland. It was established by Louis de Bougainville in 1764 as the first French settlement on the islands, but was then transferred to Spain in 1767 and renamed Puerto Soledad .-History:The settlement has seen several name changes...
, some 20 km northwest of Stanley
Stanley, Falkland Islands
Stanley is the capital and only true cityin the Falkland Islands. It is located on the isle of East Falkland, on a north-facing slope in one of the wettest parts of the islands. At the 2006 census, the city had a population of 2,115...
.
Vitosha stone rivers
Vitosha
Vitosha is a mountain massif, on the outskirts of Sofia, the capital of Bulgaria. Vitosha is one of the tourists symbols of Sofia and the closest site for hiking, alpinism and skiing. Convenient bus lines and rope ways render the mountain easily accessible. Vitosha has the outlines of an enormous...
stone rivers , located in Bulgaria
Bulgaria
Bulgaria , officially the Republic of Bulgaria , is a parliamentary democracy within a unitary constitutional republic in Southeast Europe. The country borders Romania to the north, Serbia and Macedonia to the west, Greece and Turkey to the south, as well as the Black Sea to the east...
, are situated in the middle and upper mountain belts at elevation over 1,000 m above sea level. Among the largest ones are those on the Subalpine
Subalpine
The subalpine zone is the biotic zone immediately below tree line around the world. Species that occur in this zone depend on the location of the zone on the Earth, for example, Snow Gum in Australia, or Subalpine Larch, Mountain Hemlock and Subalpine Fir in western North America.Trees in the...
plateau
Plateau
In geology and earth science, a plateau , also called a high plain or tableland, is an area of highland, usually consisting of relatively flat terrain. A highly eroded plateau is called a dissected plateau...
s surrounding the summit Cherni Vrah
Cherni Vrah
Cherni Vrah is the summit of Vitosha Mountain in Bulgaria. Rising to 2290 m, the peak is the fourth highest mountain summit in the country after Musala , Vihren , and Botev Vrah .Cherni Vrah is bounded to the northwest by Torfeno Branishte which — like the extensive adjacent...
(2290 m), and in the upper courses of the mountain’s rivers, extending over 2 km at the Zlatnite Mostove
Zlatnite Mostove
Zlatnite Mostove is the largest stone river on Vitosha Mountain, Bulgaria. The feature is situated in the valley of Vladayska River, extending 2.2 km, and up to 150 m wide, with several ‘tributary’ stone rivers. The stone river is ‘descending’ from elevation 1800 m above sea level...
(‘Golden Bridges’) site in the upper course of Vladayska River, and over 1 km in the case of Boyanska
Boyanska River
The Boyanska reka is a river in western Bulgaria, a tributary to Vladayska River.The river flows from the northern slopes of Cherni Vrah on Vitosha Mountain, crossing Torfeno Branishte Nature Reserve; at the northern foothills of Vitosha the river drops forming the Boyana waterfall and then...
, Bistritsa
Vitoshka Bistritsa
Bistritsa or Vitoshka Bistritsa , is a river in western Bulgaria, tributary of Iskar River. Flows from the eastern slopes of Golyam Rezen Peak on Vitosha Mountain, crossing Bistrishko Branishte Nature Reserve, where it forms a small but beautiful waterfall Samokovishteto, then crossing villages of...
, and Struma
Struma River
The Struma or Strymónas is a river in Bulgaria and Greece. Its ancient name was Strymōn . Its catchment area is 10,800 km²...
Rivers. Golyamata Gramada
Golyamata Gramada
Golyamata Gramada is one of the largest stone rivers on Vitosha Mountain, Bulgaria. The feature is situated in the upper valley of Vitoshka Bistritsa River in Bistrishko Branishte Nature Reserve, extending near 1 km, and up to 300 m wide...
(Big Pile) Stone River in Vitoshka Bistritsa River valley is up to 300 m wide, and other stone run formations sprawl even wider on the mountain slopes, notably the ‘stone sea’ at the northern foot of Kamen Del
Kamen Del
Kamen Del is a peak on Vitosha Mountain in Bulgaria. Rising to , and surmounting the city of Sofia, it is the most conspicuous peak seen from the Bulgarian capital. Its northern slope is partly covered by an extensive one by one km stone sea...
Peak. Some boulders are several dozen to over three hundred cubic metres in volume, and sixty to several hundred tons weight.
While Vitosha was known already to Thucydides
Thucydides
Thucydides was a Greek historian and author from Alimos. His History of the Peloponnesian War recounts the 5th century BC war between Sparta and Athens to the year 411 BC...
, Aristotle
Aristotle
Aristotle was a Greek philosopher and polymath, a student of Plato and teacher of Alexander the Great. His writings cover many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, linguistics, politics, government, ethics, biology, and zoology...
, and Pliny the Elder
Pliny the Elder
Gaius Plinius Secundus , better known as Pliny the Elder, was a Roman author, naturalist, and natural philosopher, as well as naval and army commander of the early Roman Empire, and personal friend of the emperor Vespasian...
in Antiquity
Classical antiquity
Classical antiquity is a broad term for a long period of cultural history centered on the Mediterranean Sea, comprising the interlocking civilizations of ancient Greece and ancient Rome, collectively known as the Greco-Roman world...
, its first modern geological survey
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...
was made as late as 1836 by the German
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
-French
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
-Austria
Austria
Austria , officially the Republic of Austria , is a landlocked country of roughly 8.4 million people in Central Europe. It is bordered by the Czech Republic and Germany to the north, Slovakia and Hungary to the east, Slovenia and Italy to the south, and Switzerland and Liechtenstein to the...
n scientist Ami Boué
Ami Boué
Ami Boué , Austrian geologist, was born at Hamburg, and received his early education there and in Geneva and Paris....
who incidentally had studied medicine
Medicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
at Edinburgh University
University of Edinburgh
The University of Edinburgh, founded in 1583, is a public research university located in Edinburgh, the capital of Scotland, and a UNESCO World Heritage Site. The university is deeply embedded in the fabric of the city, with many of the buildings in the historic Old Town belonging to the university...
just few years before Charles Darwin
Charles Darwin
Charles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...
did. Since Boué, it took several decades of argument to conclude that Vitosha stone rivers were not true glacial
Glacier
A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...
moraine
Moraine
A moraine is any glacially formed accumulation of unconsolidated glacial debris which can occur in currently glaciated and formerly glaciated regions, such as those areas acted upon by a past glacial maximum. This debris may have been plucked off a valley floor as a glacier advanced or it may have...
s as some believed.
Exploited in the past as a source of cobblestone
Cobblestone
Cobblestones are stones that were frequently used in the pavement of early streets. "Cobblestone" is derived from the very old English word "cob", which had a wide range of meanings, one of which was "rounded lump" with overtones of large size...
material for Sofia
Sofia
Sofia is the capital and largest city of Bulgaria and the 12th largest city in the European Union with a population of 1.27 million people. It is located in western Bulgaria, at the foot of Mount Vitosha and approximately at the centre of the Balkan Peninsula.Prehistoric settlements were excavated...
’s streets, nowadays the stone rivers are protected by law. Special permission would be granted in exceptional cases for the removal of an odd boulder for sculpture
Sculpture
Sculpture is three-dimensional artwork created by shaping or combining hard materials—typically stone such as marble—or metal, glass, or wood. Softer materials can also be used, such as clay, textiles, plastics, polymers and softer metals...
artwork. As a nature park
National park
A national park is a reserve of natural, semi-natural, or developed land that a sovereign state declares or owns. Although individual nations designate their own national parks differently A national park is a reserve of natural, semi-natural, or developed land that a sovereign state declares or...
situated right by the outskirts of Sofia
Sofia
Sofia is the capital and largest city of Bulgaria and the 12th largest city in the European Union with a population of 1.27 million people. It is located in western Bulgaria, at the foot of Mount Vitosha and approximately at the centre of the Balkan Peninsula.Prehistoric settlements were excavated...
(Cherni Vrah
Cherni Vrah
Cherni Vrah is the summit of Vitosha Mountain in Bulgaria. Rising to 2290 m, the peak is the fourth highest mountain summit in the country after Musala , Vihren , and Botev Vrah .Cherni Vrah is bounded to the northwest by Torfeno Branishte which — like the extensive adjacent...
itself being but 16 km away from the central square of Sofia), Vitosha is a major tourist destination. Some 1.5 million people from dozens of nations visit the mountain annually, and the stone rivers feature high on the list of tourist attractions.
External links
Google views
- Princes Street Stone Run, Falkland Islands
- Zlatnite Mostove (‘Golden Bridges’) Stone River, Vitosha Mountain, Bulgaria
Sources
