Petrology (from Greek: πέτρα, petra, rock; and λόγος, logos, knowledge) is the branch of geology that studies rocks, and the conditions in which rocks form.
岩石学 （希腊文：πέτρα， petra ，岩石和λόγος，标志，知识）是地质学的一个分支，专门研究岩石以及岩石形成的条件。
Lithology was once approximately synonymous with petrography, but in current usage, lithology focuses on macroscopic hand-sample or outcrop-scale description of rocks, while petrography is the speciality that deals with microscopic details.
In the oil industry, lithology, or more specifically mud logging, is the graphic representation of geological formations being drilled through, and drawn on a log called a mud log. As the cuttings are circulated out of the borehole they are sampled, examined (typically under a 10x microscope) and tested chemically when needed.
- Methodology 研究方法
- Branches 分支
- See also 另见
- References 参考文献
- External links 外部链接
Petrology utilizes the classical fields of mineralogy, petrography, optical mineralogy, and chemical analyses to describe the composition and texture of rocks. Modern petrologists also include the principles of geochemistry and geophysics through the studies of geochemical trends and cycles and the use of thermodynamic data and experiments to better understand the origins of rocks.
There are three branches of petrology, corresponding to the three types of rocks: igneous, metamorphic, and sedimentary, and another dealing with experimental techniques:
Igneous petrology focuses on the composition and texture of igneous rocks (rocks such as granite or basalt which have crystallized from molten rock or magma). Igneous rocks include volcanic and plutonic rocks.
Sedimentary petrology focuses on the composition and texture of sedimentary rocks (rocks such as sandstone, shale, or limestone which consist of pieces or particles derived from other rocks or biological or chemical deposits, and are usually bound together in a matrix of finer material).
Metamorphic petrology focuses on the composition and texture of metamorphic rocks (rocks such as slate, marble, gneiss, or schist which started out as sedimentary or igneous rocks but which have undergone chemical, mineralogical or textural changes due to extremes of pressure, temperature or both).
Experimental petrology employs high-pressure, high-temperature apparatus to investigate the geochemistry and phase relations of natural or synthetic materials at elevated pressures and temperatures. Experiments are particularly useful for investigating rocks of the lower crust and upper mantle that rarely survive the journey to the surface in pristine condition. The work of experimental petrologists has laid a foundation on which modern understanding of igneous and metamorphic processes has been built.
See Also 另见
- Important publications in petrology 岩石学的重要出版物
- Ore 金矿
External Link 外部链接
- Atlas of Igneous and metamorphic rocks, minerals, and textures – Geology Department, University of North Carolina
火成岩和变质岩，矿物和纹理地图集 – 北卡罗莱纳大学地质学系
- Metamorphic Petrology Database (MetPetDB) – Department of Earth and Environmental Sciences, Rensselaer Polytechnic Institute
- Petrological Database of the Ocean Floor (PetDB) – Center for International Earth Science Information Network (CIESIN), Columbia University
- Petrology 岩石学
- Petroleum geology 石油地质学
- Oilfield terminology 油田术语
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Source > Wikipedia at en.wikipedia.org/wiki/Petrology
Translated by > BlogHost
Word Count > approx. 580 words in English
Baleen or whalebone is a filter-feeder system inside the mouths of baleen whales. The baleen system works when a whale opens its mouth underwater and then water pours into the whale’s mouth. The whale then pushes the water out, and animals such as krill are filtered by the baleen and remain as food source for the whale. Baleen is similar to bristles and is made of keratin, the same substance found in human fingernails and hair. Some whales, such as the bowhead whale, have longer baleen than others. Others whales, such as the gray whale, only use one side of their baleen. These baleen bristles are arranged in plates across the upper jaw of the whale.
Depending on the species, a baleen plate can be 0.5 to 3.5 metres (1.6 to 11 ft) long, and weigh up to 90 kilograms (200 lb). Its hairy fringes are called baleen hair or whalebone-hair. They are also called baleen bristles, which in sei whales are highly calcified, calcification functioning to increase their stiffness. Baleen plates are broader at the gumline (base). The plates have been compared to sieves or Venetian blinds.
- Etymology 词源
- Evolution 进化
- Filter feeding 滤食性能
- Human uses 人类用途
- As a habitat 栖息地
- References 参考资料
- Further reading 其他读物
The word “baleen” derives from Early Modern English word meaning “whale”. This in turn derives from the Latin balaena, related to the Greek phalaina – both of these also mean “whale”.
“鲸须”一词源自于早期的现代英语单词，意思是“ 鲸鱼 ”,也是出自拉丁文的balaena，跟希腊文的phalaina有关，两者的意思都是”鲸鱼”.
The oldest true fossils of baleen are only 15 million years old, but baleen rarely fossilizes, and scientists believe it originated considerably earlier than that. This is indicated by baleen-related skull modifications being found in fossils from considerably earlier, including a buttress of bone in the upper jaw beneath the eyes, and loose lower jaw bones at the chin. Baleen is believed to have evolved around thirty million years ago, possibly from a hard, gummy upper jaw, like the one a Dall’s porpoise has. In fact, it resembles baleen closely at the microscopic level.
Many early baleen whales also had teeth, but these were probably used only peripherally, or perhaps not at all (again like Dall’s porpoise, which catches squid and fish by gripping them against its hard upper jaw).
Filter Feeding 滤食性能
A whale’s baleen plates play the most important role in its filter-feeding process. In order to feed, a baleen whale opens its mouth widely and scoops in dense shoals of prey (such as krill, copepods, small fish and sometimes birds that happen to be near the shoals), together with large volumes of water. It then partly shuts its mouth and presses its tongue against its upper jaw, forcing the water to pass out sideways through the baleen, thus sieving out the prey which it then swallows.
Human Uses 人类用途
People formerly used baleen for making numerous items where flexibility and strength were required, including collar stiffeners, buggy whips and parasol ribs, and as corset stays. It was commonly used to crease paper; its flexibility kept it from damaging the paper. It was also occasionally used in cable-backed bows. Synthetic materials are now usually used for similar purposes, especially plastic and fibre glass. Baleen was frequently used in the 18th and early 19th centuries as the handle for silver punch or toddy ladles. It was chosen for this use because of its insulating qualities. Baleen plates are also used by indigenous people to create fine crafts.
As a Habitat 栖息地
Baleen serves as a habitat for some species from the gastropod families Pyropeltidae, Cocculinidae, Osteopeltidae and Neolepetopsidae.
See Also 另见
- John Henry Devereux South Carolina architect who used whale jaw bones to adorn the largest mansion on Sullivan’s Island.
南卡罗来纳州的建筑师John Henry Devereux约翰亨利德弗罗用鲸鱼颚骨来装饰Sullivan苏里曼岛上最大的豪宅。
- Cetaceans 鲸类动物
- Whale Products 鲸鱼产品
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Source > Wikipedia at en.wikipedia.org/wiki/Baleen
Translated by > BlogHost
Word Count > approx. 630 words in English