Age of the Earth research. Most geological samples from Earth are unable to give a direct date of the formation of Earth from the solar nebula because Earth has undergone differentiation into the core, mantle, and crust, and this has then undergone a long history of mixing and unmixing of these sample reservoirs by plate tectonics, weathering and hydrothermal circulation. All of these processes may adversely affect isotopic dating mechanisms because the sample cannot always be assumed to have remained as a closed system, by which it is meant that either the parent or daughter nuclide (a species of atom characterised by the number
What We Do Elation" (1995). All tracks written by John Scofield. What We Do What We Do is the second studio album by jazz group The John Scofield Quartet. It was recorded in May 1992 and released the following year on the Blue Note label. Besides John Scofield on guitar, the quartet features saxophonist Joe Lovano, Bill Stewart on drums and Dennis Irwin on bass, replacing Marc Johnson. Irwin and Scofield (both born in 1951) had already recorded together in the mid-1980s with Bennie Wallace on a track for his album "Sweeping Through the City." Irwin would be the bassist on two more