Magma is a mixture of molten and semi-molten rock found below Earth's surface. Most magma consists of four types of materials: liquid rock, crystallized minerals, solid pieces of rock, and dissolved gases. When magma escapes through a volcano onto Earth's surface, scientists call it lava.
Download the Accretion of Duties Form (PDF, 8K) An accretion of duties is a promotion resulting from the upgrading of an employee's position because of additional duties and responsibilities. Jobs change and evolve for many reasons.
From Wikipedia, the free encyclopedia. Artist's conception of a binary star system with one black hole and one main sequence star. An accretion disc (or accretion disk) is an astronomical term. It describes a disc of material being drawn in by gravity to a centre of mass, such as a star or black hole. As the material comes in, it spins round the central body and radiates energy.