Structure of the Earth discontinuity (a second order discontinuity). The uppermost mantle together with the crust constitutes the lithosphere. The crust-mantle boundary occurs as two physically different events. First, there is a discontinuity in the seismic velocity, which is most commonly known as the Mohorovičić discontinuity or Moho. The cause of the Moho is thought to be a change in rock composition from rocks containing plagioclase feldspar (above) to rocks that contain no feldspars (below). Second, in oceanic crust, there is a chemical discontinuity between ultramafic cumulates and tectonized harzburgites, which has been observed from deep parts of the oceanic crust that have been
The Upper Crust (band) The Upper Crust (band) The Upper Crust is an American hard rock band from Boston, Massachusetts. The members adopt the personae of 18th century aristocratic fops and sing songs from that perspective. They use titles of nobility, wear powdered wigs and period costumes, and maintain a snobbish attitude both during live performance and on their albums. The members say that their guiding philosophy is "if not great and excellent, then debauched." Their major music influence is Bon Scott-era AC/DC, along with glam rock band Kiss and fictional heavy metal band Spinal Tap. "Rolling Stone" wrote, "[d]ismiss Boston's Upper Crust as