Oregon | Capital, Map, Population, & Facts | Britannica
2 天之前 · The forested mountains of western and northeastern Oregon have supplied the traditional core of the state’s economy. Its many forest-product plants produce a major portion of the country’s softwood lumber, much of its soft plywood, and large quantities of hardboard, pulp, and paper.Nationally, Oregon ranks at or near the top among all states in the production of …
Rock | Definition, Characteristics, Formation, Cycle, Classification ...
2024年10月22日 · rock, in geology, naturally occurring and coherent aggregate of one or more minerals. Such aggregates constitute the basic unit of which the solid Earth is composed and typically form recognizable and mappable volumes. Rocks are commonly divided into three major classes according to the processes that resulted in their formation. These classes are (1) …
Sedimentary rock | Definition, Formation, Examples,
2024年10月30日 · sedimentary rock, rock formed at or near Earth’s surface by the accumulation and lithification of sediment (detrital rock) or by the precipitation from solution at normal surface temperatures (chemical rock). Sedimentary rocks are the most common rocks exposed on Earth’s surface but are only a minor constituent of the entire crust, which is dominated by igneous and …
Igneous rock | Characteristics, Examples, Formation, & Types
2024年11月12日 · Igneous rock, any of various crystalline or glassy rocks formed by the cooling and solidification of magma, which is a hot (600 to 1,300 °C, or 1,100 to 2,400 °F) molten or partially molten rock. Igneous rocks constitute one of the three principal classes of rocks, the others being metamorphic and sedimentary.
Rock and roll | History, Songs, Artists, & Facts | Britannica
2024年10月23日 · Rock and roll, style of popular music that originated in the United States in the mid-1950s and that evolved by the mid-1960s into the more encompassing international style known as rock music, though the latter also continued to be known as rock and roll. Learn more about the history of rock and roll in this article.
Rock | Definition, History, Artists, Songs, & Facts | Britannica
rock, form of popular music that emerged in the 1950s.. It is certainly arguable that by the end of the 20th century rock was the world’s dominant form of popular music. Originating in the United States in the 1950s, it spread to other English-speaking countries and across Europe in the ’60s, and by the ’90s its impact was obvious globally (if in many different local guises).
Metamorphic rock | Definition, Formation, & Facts | Britannica
4 天之前 · Metamorphic rock, any rock that results from the alteration of preexisting rocks in response to changing conditions, such as variations in temperature, pressure, and mechanical stress, and the addition or subtraction of chemical components. The preexisting rocks may be igneous, sedimentary, or other metamorphic rocks.
Rock - Social Change, Cultural Evolution, Music Revolution
Rock - Social Change, Cultural Evolution, Music Revolution: How, then, should rock’s contribution to music history be judged? One way to answer this is to trace rock’s influences on other musics. Another is to attempt a kind of cultural audit. (What is the ratio of rock masterworks to rock dross?) But such approaches come up against the problem of definition.
Definition, Properties, Color, Applications, & Facts - Britannica
6 天之前 · A diamond is a mineral composed of pure carbon. It is the hardest naturally occurring substance known; it is also the most popular gemstone. Because of their extreme hardness, diamonds have a number of important industrial applications.
Rocky Mountains | Location, Map, History, & Facts | Britannica
2024年11月17日 · Rocky Mountains, mountain range forming the cordilleran backbone of the great upland system that dominates the western North American continent. Generally, the ranges included in the Rockies stretch from northern Alberta and British Columbia southward to New Mexico, a distance of some 3,000 miles (4,800 km).In places the system is 300 or more miles …