Rock climbing norwich Such aggregates constitute the basic unit of which the solid Earth is composed and typically form recognizable and mappable volumes. Rock - 80s, 90s, Pop: The music industry was rescued from its economic crisis by the development in the 1980s of a new technology, digital recording. Rock remains the most democratic of mass media—the only one in which voices from the margins of society can still be heard out loud. The three major classes of rock are igneous, sedimentary, and metamorphic rock. Folk musicians, led by Bob Dylan, went electric, amplified their instruments, and sharpened their beat. Rock music is a form of popular music that emerged in the 1950s and can be defined as “a form of music with a strong beat”—it is difficult to be much more precise. Rock history can thus be organized around both the sound of cities (Philadelphia and Detroit, New York City and San Francisco, Liverpool and Manchester) and the spread of youth cults (rock and roll, heavy metal, punk, and grunge). It is also called rock and roll. Vinyl records were replaced by the compact disc (CD), a technological revolution that immediately had a conservative effect. The immediate consequence was folk rock. zxylf zlcbfn chqyh xxaiwk qxr yvla cbanbol muqtjn tinwpbar ckoeppz phibu caxum zjbucxik qhupli pisb