Trap rock
Encyclopedia
Magma
Magma is a mixture of molten rock, volatiles and solids that is found beneath the surface of the Earth, and is expected to exist on other terrestrial planets. Besides molten rock, magma may also contain suspended crystals and dissolved gas and sometimes also gas bubbles. Magma often collects in...
of suitable chemical composition (typically basalt
Basalt
Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey...
ic) intrudes as a sill
Sill (geology)
In geology, a sill is a tabular sheet intrusion that has intruded between older layers of sedimentary rock, beds of volcanic lava or tuff, or even along the direction of foliation in metamorphic rock. The term sill is synonymous with concordant intrusive sheet...
or extrudes as a thick lava
Lava
Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...
flow, and slowly cools.
Because of the regular vertical fracture planes plus frequent horizontal fractures, trap rock tends to appear in orderly structures resembling piles of blocks, sometimes reminiscent of stairs and inspiring the term "trap", which comes from a Scandinavian word meaning "steps" or "stairs".
Trap rock is commercially quarried
Quarry
A quarry is a type of open-pit mine from which rock or minerals are extracted. Quarries are generally used for extracting building materials, such as dimension stone, construction aggregate, riprap, sand, and gravel. They are often collocated with concrete and asphalt plants due to the requirement...
and crushed to provide hard bulk in composite materials that bond it together, such as concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
and macadam
Macadam
Macadam is a type of road construction pioneered by the Scotsman John Loudon McAdam in around 1820. The method simplified what had been considered state-of-the-art at that point...
.
Trap rock is the primary constituent of many ridges and other rock outcrops in the Hudson River
Hudson River
The Hudson is a river that flows from north to south through eastern New York. The highest official source is at Lake Tear of the Clouds, on the slopes of Mount Marcy in the Adirondack Mountains. The river itself officially begins in Henderson Lake in Newcomb, New York...
valley, such as the Palisades
New Jersey Palisades
The Palisades, also called the New Jersey Palisades or the Hudson Palisades are a line of steep cliffs along the west side of the lower Hudson River in northeastern New Jersey and southern New York in the United States. The cliffs stretch north from Jersey City approximately 20 mi to near...
, and southern New England
New England
New England is a region in the northeastern corner of the United States consisting of the six states of Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, and Connecticut...
.
The Deccan traps
Deccan Traps
The Deccan Traps are a large igneous province located on the Deccan Plateau of west-central India and one of the largest volcanic features on Earth. They consist of multiple layers of solidified flood basalt that together are more than thick and cover an area of and a volume of...
and Siberian traps
Siberian Traps
The Siberian Traps form a large region of volcanic rock, known as a large igneous province, in the Russian region of Siberia. The massive eruptive event which formed the traps, one of the largest known volcanic events of the last 500 million years of Earth's geological history, continued for...
are vast areas of basaltic volcanism
Volcanism
Volcanism is the phenomenon connected with volcanoes and volcanic activity. It includes all phenomena resulting from and causing magma within the crust or mantle of a planet to rise through the crust and form volcanic rocks on the surface....
in India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
and Siberia
Siberia
Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...
respectively.
See also
- Devils Postpile National MonumentDevils Postpile National MonumentDevils Postpile National Monument is located near Mammoth Mountain in extreme northeastern Madera County in eastern California. It was established in 1911, and protects Devils Postpile, an unusual formation of columnar basalt.-Geography:...
- Giant's CausewayGiant's CausewayThe Giant's Causeway is an area of about 40,000 interlocking basalt columns, the result of an ancient volcanic eruption. It is located in County Antrim on the northeast coast of Northern Ireland, about three miles northeast of the town of Bushmills...
- Organ Pipes National ParkOrgan Pipes National ParkThe Organ Pipes National Park , a protected area, is located in Victoria, Australia. It was established with the focus on conservation of the native flora and fauna, and preservation of the geological features in the Jackson Creek, a part of the Maribyrnong valley, north-west of Melbourne...