Lithosphere for silicate rocks, and formula_4 is the age of the given part of the lithosphere. The age is often equal to L/V, where L is the distance from the spreading centre of mid-oceanic ridge, and V is velocity of the lithospheric plate. Oceanic lithosphere is less dense than asthenosphere for a few tens of millions of years but after this becomes increasingly denser than asthenosphere. This is because the chemically differentiated oceanic crust is lighter than asthenosphere, but thermal contraction of the mantle lithosphere makes it more dense than the asthenosphere. The gravitational instability of mature oceanic lithosphere has the
Salt of the Earth (song) Jagger and Richards using a personal tape recorder, "Salt of the Earth" was recorded at London's Olympic Sound Studios in May 1968. Featuring on the song are the Los Angeles Watts Street Gospel Choir and a piano performance by Nicky Hopkins. These additions, and their prominence near the end of the song, are further developed on their next album "Let It Bleed"'s closing song, "You Can't Always Get What You Want". "Salt of the Earth" has a unique live history. It has only been played once to an instrumental playback and live five times. Salt of the Earth (song) "Salt