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
The Lord of the Rings: The Battle for Middle-earth of "The Battle for Middle-earth" sold 230,000 copies and earned $9.4 million by August 2006, after its release in December 2004. It was the country's 89th best-selling computer game during this period. It received a "Gold" sales award from the Entertainment and Leisure Software Publishers Association (ELSPA), indicating sales of at least 200,000 copies in the United Kingdom. The critical response to "The Battle for Middle-earth" was fairly positive. The video game review aggregator GameRankings displays an average critic score of 82.5%, with about two-thirds of the reviews in the 80%s. IGN praised the game for its visual flair and