geology Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Ear ...

, a boulder (or rarely bowlder) is a

rock Rock most often refers to: * Rock (geology), a naturally occurring solid aggregate of minerals or mineraloids * Rock music, a genre of popular music Rock or Rocks may also refer to: Places United Kingdom * Rock, Caerphilly, a location in Wales ...

fragment with size greater than in diameter. Smaller pieces are called

cobbles Cobblestone is a natural building material based on cobble-sized stones, and is used for pavement roads, streets, and buildings. Setts, also called Belgian blocks, are often casually referred to as "cobbles", although a sett is distinct fro ...

and

pebble A pebble is a clast of rock with a particle size of based on the Udden-Wentworth scale of sedimentology. Pebbles are generally considered larger than granules ( in diameter) and smaller than cobbles ( in diameter). A rock made predominant ...

s. While a boulder may be small enough to move or roll manually, others are extremely massive. In common usage, a boulder is too large for a person to move. Smaller boulders are usually just called

s or stones. The word ''boulder'' derives from ''boulder stone'', from the

Middle English Middle English (abbreviated to ME) is a form of the English language that was spoken after the Norman conquest of 1066, until the late 15th century. The English language underwent distinct variations and developments following the Old English p ...

''bulderston'' or

Swedish Swedish or ' may refer to: Anything from or related to Sweden, a country in Northern Europe. Or, specifically: * Swedish language, a North Germanic language spoken primarily in Sweden and Finland ** Swedish alphabet, the official alphabet used by ...

''bullersten''.boulder. (n.d.)
Online Etymology Dictionary. Retrieved December 9, 2011, from Dictionary.com website. In places covered by

ice sheet In glaciology, an ice sheet, also known as a continental glacier, is a mass of glacial ice that covers surrounding terrain and is greater than . The only current ice sheets are in Antarctica and Greenland; during the Last Glacial Period at Las ...

s during

ice age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gree ...

s, such as

Scandinavia Scandinavia; Sámi languages: /. ( ) is a subregion#Europe, subregion in Northern Europe, with strong historical, cultural, and linguistic ties between its constituent peoples. In English usage, ''Scandinavia'' most commonly refers to Denmark, ...

, northern

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

, and

Siberia Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part of ...

glacial erratic A glacial erratic is glacially deposited rock differing from the type of rock native to the area in which it rests. Erratics, which take their name from the Latin word ' ("to wander"), are carried by glacial ice, often over distances of hundred ...

s are common. Erratics are boulders picked up by ice sheets during their advance, and deposited when they melt. These boulders are called "erratic" because they typically are of a different rock type than the

bedrock In geology, bedrock is solid Rock (geology), rock that lies under loose material (regolith) within the crust (geology), crust of Earth or another terrestrial planet. Definition Bedrock is the solid rock that underlies looser surface mater ...

on which they are deposited. One such boulder is used as the

pedestal A pedestal (from French ''piédestal'', Italian ''piedistallo'' 'foot of a stall') or plinth is a support at the bottom of a statue, vase, column, or certain altars. Smaller pedestals, especially if round in shape, may be called socles. In ci ...

the Bronze Horseman The ''Bronze Horseman'' (russian: link=no, Медный всадник, literally "copper horseman") is an equestrian statue of Peter the Great in the Senate Square in Saint Petersburg, Russia. It was opened to the public on 7 (18) August ...

Saint Petersburg Saint Petersburg ( rus, links=no, Санкт-Петербург, a=Ru-Sankt Peterburg Leningrad Petrograd Piter.ogg, r=Sankt-Peterburg, p=ˈsankt pʲɪtʲɪrˈburk), formerly known as Petrograd (1914–1924) and later Leningrad (1924–1991), i ...

, Russia. Some noted

rock formation A rock formation is an isolated, scenic, or spectacular surface rock outcrop. Rock formations are usually the result of weathering and erosion sculpting the existing rock. The term ''rock formation'' can also refer to specific sediment ...

s involve giant boulders exposed by

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...

, such as the Devil's Marbles in

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

Northern Territory The Northern Territory (commonly abbreviated as NT; formally the Northern Territory of Australia) is an states and territories of Australia, Australian territory in the central and central northern regions of Australia. The Northern Territory ...

, the

Horeke basalts The Horeke basalts is a disused formation that contained Miocene-Pliocene basalt lava flows that covered a large area in central Northland Region of New Zealand, and in places forms a high plateau around Okaihau. Wairere Boulders is a nature ...

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

, where an entire

valley A valley is an elongated low area often running between Hill, hills or Mountain, mountains, which will typically contain a river or stream running from one end to the other. Most valleys are formed by erosion of the land surface by rivers ...

contains only boulders, and

The Baths The Baths is a beach area on the island of Virgin Gorda among the British Virgin Islands in the Caribbean. Geography The Baths is situated about south off the maintown Spanish Town at the southern tip of the island between Spring Bay and Devil' ...

on the island of

Virgin Gorda Virgin Gorda () is the third-largest island (after Tortola and Anegada) and second-most populous of the British Virgin Islands (BVI). Geography Located at about 18 degrees, 48 minutes North, and 64 degrees, 30 minutes West, it covers an area o ...

in the

British Virgin Islands ) , anthem = "God Save the King" , song_type = Territorial song , song = "Oh, Beautiful Virgin Islands" , image_map = File:British Virgin Islands on the globe (Americas centered).svg , map_caption = , mapsize = 290px , image_map2 = Brit ...

. Boulder-sized

clast Clastic rocks are composed of fragments, or clasts, of pre-existing minerals and rock. A clast is a fragment of geological detritus,Essentials of Geology, 3rd Ed, Stephen Marshak, p. G-3 chunks, and smaller grains of rock broken off other rocks ...

s are found in some

sedimentary rock Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...

s, such as coarse conglomerate and

boulder clay Boulder clay is an unsorted agglomeration of clastic sediment that is unstratified and structureless and contains gravel of various sizes, shapes, and compositions distributed at random in a fine-grained matrix. The fine-grained matrix consists ...

. The climbing of large boulders is called

bouldering Bouldering is a form of free climbing that is performed on small rock formations or artificial rock walls without the use of ropes or harnesses. While bouldering can be done without any equipment, most climbers use climbing shoes to help sec ...

References

External links

{{Authority control Rocks Rock formations Garden features Natural materials

See also

References

External links