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
What Hurts the Most Credits taken from "Perfect Day" liner notes. What Hurts the Most "What Hurts the Most" is a song written by American songwriter Jeffrey Steele and English songwriter Steve Robson. Initially recorded by country music artist Mark Wills in 2003 on his album "And the Crowd Goes Wild", it was covered by Bellefire a year later. The first version to be released as a single was by pop singer Jo O'Meara in 2005, from the album "Relentless". Later that year, country band Rascal Flatts covered the song as well, releasing it as the first single from the 2006 album "Me and