An orogeny is underway when mountains begin to grow in the collision zone. There are other modes of mountain formation and orogeny but certainly continental collision is one of the most important. Rainfall and snowfall increase on the mountains as these rise, perhaps at a rate of a few millimeters per year (at a growth rate of 1 mm/year, a 5,000m tall mountain can form in 5 million years, a time period that is less than 10% of the life of a typical collision zone). River systems form, and glaciers may grow on the highest peaks. Erosion accel ...
Epizoanthidae
Parazoanthidae
Zoanthidae
Zoanthids (order Zoanthidea) are a type of soft coral commonly found in coral reefs all around the world. These animals come in a variety of different colonizing formations and in numerous colors. They can be found as individual polyps, attached by a fleshy stolon or a mat that can be created from pieces of sediment, sand and rock. There are a large amount of different morphs of the same or similar species depending on the location on the reef each colony occupies ...
Coastal defenses are objects and engineering techniques used to defend coasts against erosion and flooding. These may be hard engineering or soft engineering. In England and Wales, the term Coastal Protection is used to describe protection of the coast against erosion whilst the term Sea Defences is used from protection against flooding
Hard engineering techniques involve building rock or concrete structures, most commonly sea walls, jetties, rock islands, rock aprons and breakwaters. Piles of large rocks are especially efficient at dissipating wave energy as they ...
Argyre Planitia is a plain located in the Argyre impact basin in the southern highlands of Mars. Its name comes from a map produced by Giovanni Schiaparelli in 1877; it refers to Argyre, a mythical island of silver in Greek mythology.
Argyre lies between -35 and -61 deg S and 27 and 62 deg W. The basin is approximately 1120 miles (1800 kilometers) wide, the second-largest impact basin on Mars after Hellas Planitia, and drops 3. ...
Radiocarbon dating is a radiometric dating method that uses the naturally occurring isotope carbon-14 to determine the age of carbonaceous materials up to ca 60,000 years. Within archaeology it is considered an absolute dating technique. The technique was discovered by Willard Frank Libby and his colleagues in 1949. In 1960, Libby was awarded the Nobel Prize in chemistry for radiocarbon dating.
Radiocarbon dating - Basic chemistry.
Carbon has two stable, nonradioactive isotopes: carbon-12 (12C), ...
Calcareous refers to a sediment, sedimentary rock, or soil type which is formed from or contains a high proportion of calcium carbonate in the form of calcite or aragonite.
It is also used to refer to relatively alkaline soil. Frequently this is indeed due to a high calcareous content but there are other causes for a high soil pH.
Calcareous coatings, or calcareous deposits, are mixtures of calcium carbonate and magnesium hydroxide that are deposited on cathodically protected surfaces because of the increas ...
Bryozoans are tiny colonial animals that generally build stony skeletons of calcium carbonate, superficially similar to coral. They are also known as moss animals or sea mats. They generally prefer warm, tropical waters but even today are known to occur worldwide. There are about 5,000 living species, with several times that number of fossil forms known.
Most species of Bryozoan live in marine environments, though there are about 50 species which inhabit freshwater. In their aquatic habitats, bryozoans may be foun ...
Continental collision is a phenomenon of the plate tectonics of our solid Earth. Continental collision is a variation on the fundamental process of subduction, whereby the subduction zone is destroyed, mountains produced, and two continents sutured together. Continental collision is known only from this planet and is an interesting example of how our different crusts, oceanic and continental, behave during subduction.
Continental collision is not an instantaneous event, like a car crash, but may take several tens of millions of ...
A varve is an annual layer of sediment or sedimentary rock.
The word Varve is derived from the Swedish word varv whose meanings and connotations include revolution, in layers, and circle. The term first appeared as Hvarfig lera (varved clay) on the first map produced by the Geological Survey of Sweden in 1862. Initially, varve was used to describe the separate components of annual layers in glacial lake sediments, but at the 1910 Geological Congress, the Swedish geologist Gerard De Geer ...
A dam is a barrier across flowing water that obstructs, directs or retards the flow, often creating a reservoir, lake or impoundment. Most dams have a section called a spillway or weir over which or through which it is intended that water will flow either intermittently or continuously.
Dam - Types of dams.
Dams may be classified according to structure, intended purpose or height.
Based on structure and material used, dams are classified as timber dams, embankment dams or masonry ...
The second USS Thresher (SSN-593) was the lead ship of her class of nuclear-powered attack submarines in the United States Navy. Her loss at sea during deep-diving tests is often considered a watershed event in the implementation of a rigorous submarine safety program called SubSafe.
She was named for a type of shark that is harmless to man and easily recognizable because its tail is longer than the combined length of body and head.
The contract to build her was awarded to Portsmouth Naval Shipyard on 15 January 1 ...
USS Scorpion (SSN-589) was the sixth ship of the United States Navy to be named for the scorpion, (hence the Scorpius constellation on its insignia). She was a Skipjack-class nuclear submarine of the United States Navy. She was one of the few American submarines to be lost at sea while not at war and to date is one of only two nuclear subs the U.S. Navy has ever lost. She was also the last nuclear sub lost by the Navy; the first was the USS Thresher which sank in April 1963 off the coast of New England. Scorpion sank on ...
To braid is to interweave or twine three or more separate strands of one or more materials in a diagonally overlapping pattern. The word is used in many contexts:
As a noun, braid refers to any object created by such weaving, particularly if it remains in a strand or rope-like configuration. Simple braids with more than three strands can be flat or tubular and generally contain an odd number of strands. Complex braids have been used to create hanging fiber artworks.
Braiding of fiber yarn creates a strand or rope ...
History of creationism
Creation in Genesis
Types of creationism:
Young Earth creationism
- Creation science
Old Earth creationism
Omphalos creationism
Theistic evolution
Neo-Creationism
Islamic creationism
Intelligent design
- Intelligent design movement
Modern geocentrism
Controversy:
Creation vs. evolution
... in public education
Associated articles
Teach the Controversy
Irreducible ...
To most people not professionally involved in water quality issues, water is either drinkable (technically potable) or contains potentially harmful or toxic substances. However, the vast majority of surface water on the planet is neither potable nor toxic. This remains true even if we eliminate from consideration the more than 97% of the earth's water found in the oceans (sea water)—too salty to drink. Another general perception of water quality is that of a simple property that tells whether water is polluted o ...
A braided river channel consists of a network of smaller channels separated by small and often temporary islands called braid bars. Braided streams are common wherever a drastic reduction in stream gradient causes the rapid deposition of the stream's sediment load. Braided channels are also typical of river deltas.
The channels and braid bars are usually highly mobile, with the river layout often changing significantly during flood events. Channels move sideways via differential velocity: On the outside of a curve, deeper, swift water picks up sediment (usually gravel or larger stones), which is re-dep ...
A glacier is a large, long-lasting river of ice that is formed on land and moves in response to gravity. A glacier is formed by multi-year ice accretion in sloping terrain. Glacier ice is the largest reservoir of fresh water on Earth, and second only to the oceans as the largest reservoir of total water. Glaciers can be found on every continent except Australia.
Geologic features associated with glaciers include end, lateral, ground and medial moraines that form from glacially tran ...
The white cliffs of Dover, immortalized in popular song and verse (by Vera Lynn, Kate Smith, Matthew Arnold, Eric Johnson and others), are cliffs facing the Strait of Dover near the major English port town of Dover, in the county of Kent, and form part of the North Downs. The cliff face, which reaches up to 350 feet high, owes its striking façade to its composition of chalk (pure white lime) accentuated by streaks of black flint.
An alluvial plain is a relatively flat and gently sloping landform found at the base of a range of hills. As the hills erode due to weathering and water flow the sediment from the hills is transported to the lower plain. Various creeks will carry the water further to a river, lake, bay, or ocean. As the sediments are deposited during flood conditions in the floodplain of the creek, the elevation of the floodplain will be raised. As this reduces the channel floodwater capacity, the creek will over time seek new, lower paths, forming me ...
An alluvial deposit is an accumulation of alluvium (sediment), sometimes containing valuable ore and gemstones, or simply consisting of gravel, sand, or clay, in the bed or former bed of a river. Valuable materials such as gold may be extracted using techniques of placer mining. Historically, gemstones (diamonds in particular), were found in the gravels of India. They continue to be mined from alluvium in Myanmar and Sri L ...
