Boulder in the context of "Drift (geology)"

Gravel (/ˈɡrævəl/) is a loose aggregation of rock fragments. Gravel occurs naturally on Earth as a result of sedimentary and erosive geological processes; it is also produced in large quantities commercially as crushed stone.

Gravel is classified by particle size range and includes size classes from granule- to boulder-sized fragments. In the Udden-Wentworth scale gravel is categorized into granular gravel (2–4 mm or 0.079–0.157 in) and pebble gravel (4–64 mm or 0.2–2.5 in). ISO 14688 grades gravels as fine, medium, and coarse, with ranges 2–6.3 mm (0.079–0.248 in) for fine and 20–63 mm (0.79–2.48 in) for coarse. One cubic metre of gravel typically weighs about 1,800 kg (4,000 lb), or one cubic yard weighs about 3,000 lb (1,400 kg).

Substrate is the earthy material that forms or collects at the bottom of an aquatic habitat. It is made of sediments that may consist of:

• Silt – A loose, granular material with mineral particles 0.5 mm or less in diameter.
• Clay – A smooth, fine-grained material made of fine particles of hydrous aluminium phyllosilicate minerals (such as kaolinite).
• Mud – A mixture of water with silt, clay, or loam.
• Sand – Mineral particles between 0.06 and 2 mm in diameter.
• Granule – Between 2 and 4 mm in diameter.
• Pebble – Between 4 – 64 mm in diameter.
• Cobble – between 6.4 and 25.6 cm in diameter
• Boulder – more than 25.6 cm in diameter.
• Other, assorted organic matter, detritus.

Stream substrate can affect the life found within the stream habitat. Muddy streams generally have more sediment in the water, reducing clarity. Clarity is one guide to stream health.

A shingle beach, also known as either a cobble beach or gravel beach, is a commonly narrow beach that is composed of coarse, loose, well-rounded, and waterworn gravel, called shingle. The gravel (shingle) typically consists of smooth, spheroidal to flattened, pebbles, cobbles, and sometimes small boulders, generally in the 2 to 20 centimetres (0.8 to 7.9 in) size range. Shingle beaches typically have a steep slope on both their landward and seaward sides. Shingle beaches form in wave-dominated locations where resistant bedrock cliffs provide gravel-sized rock debris. They are also found in high latitudes and temperate shores where the erosion of Quaternary glacial deposits provide gravel-size rock fragments. This term is most widely used in Great Britain.

While this type of beach is most commonly found in Europe, examples are also found in Bahrain, North America, and a number of other world regions, such as the west coast of New Zealand's South Island, where they are associated with the shingle fans of braided rivers. Though created at shorelines, post-glacial rebound can raise shingle beaches as high as 200 metres (660 ft) above sea level, as on the High Coast in Sweden.

A ribbon lake is a long and very deep, finger-shaped lake, usually found in a glacial trough. As such, a ribbon lake is one of a number of glacial landscapes, including arêtes, corries, rock lips, rock basins and terminal moraines.

Such a lake's formation begins when a glacier moves over an area containing alternate bands of hard and soft bedrock. The sharp-edged boulders that are picked up by the glacier and carried at the bottom of the glacier erode the softer rock more quickly by abrasion, thus creating a hollow called a rock basin. On either side of the rock basin, the more resistant rock is eroded less and these outcrops of harder rock are known as rock bars, which act as dams between which rainwater may accumulate after the retreat of the ice age, filling up the rock basin and creating a ribbon lake. A ribbon lake may also form behind a terminal or recessional moraine, both of which also act as dams, enabling water to accumulate behind them.

A cobble (also sometimes called a cobblestone) is a clast of rock defined on the Udden–Wentworth scale as having a particle size of 64–256 millimeters (2.5–10.1 in), larger than a pebble and smaller than a boulder. Other scales define a cobble's size differently. A rock made predominantly of cobbles is termed a conglomerate. Cobblestone is a building material based on cobbles.

Frost weathering is a collective term for several mechanical weathering processes induced by stresses created by the freezing of water into ice. The term serves as an umbrella term for a variety of processes, such as frost shattering, frost wedging, and cryofracturing. The process may act on a wide range of spatial and temporal scales, from minutes to years and from dislodging mineral grains to fracturing boulders. It is most pronounced in high-altitude and high-latitude areas and is especially associated with alpine, periglacial, subpolar maritime, and polar climates, but may occur anywhere at sub-freezing temperatures (between −3 and −8 °C (27 and 18 °F)) if water is present.

Grain size (or particle size) is the diameter of individual grains of sediment, or the lithified particles in clastic rocks. The term may also be applied to other granular materials. This is different from the crystallite size, which refers to the size of a single crystal inside a particle or grain. A single grain can be composed of several crystals. Granular material can range from very small colloidal particles, through clay, silt, sand, gravel, and cobbles, to boulders.

127 Hours is a 2010 biographical drama film co-written, produced, and directed by Danny Boyle. The film mainly stars James Franco, with Kate Mara, Amber Tamblyn, and Clémence Poésy appearing in brief supporting roles. In the film, canyoneer Aron Ralston must find a way to escape after he gets trapped by a boulder in an isolated slot canyon in Bluejohn Canyon, southeastern Utah, in April 2003. It is a British and American venture produced by Pathé, Everest Entertainment, Film4 Productions, HandMade Films and Cloud Eight Films.

The film, based on Ralston's memoir Between a Rock and a Hard Place (2004), was written by Boyle and Simon Beaufoy, co-produced by Christian Colson and John Smithson, and scored by A. R. Rahman. Beaufoy, Colson, and Rahman had all previously worked with Boyle on Slumdog Millionaire (2008). 127 Hours premiered at the Telluride Film Festival on 4 September 2010, and was released in the United States on 5 November 2010 and in the United Kingdom on 7 January 2011. It was acclaimed by critics and audiences and grossed $60.7 million worldwide. It was selected by the American Film Institute as one of the top 10 films of 2010 and was nominated for six Academy Awards, including Best Actor for Franco and Best Picture. The film also received nominations for eight British Academy Film Awards and three Golden Globe Awards.