Crust (geology) centers, where partial-melting of the underlying mantle yields basaltic magmas and new ocean crust forms. This "ridge push" is one of the driving forces of plate tectonics, and it is constantly creating new ocean crust. That means that old crust must be destroyed somewhere, so, opposite a spreading center, there is usually a subduction zone: a trench where an ocean plate is being shoved back into the mantle. This constant process of creating new ocean crust and destroying old ocean crust means that the oldest ocean crust on Earth today is only about 200 million years old. In contrast, the
1066 The Battle for Middle Earth and Hastings, the little village was, according to the book, "laid to waste" in 1066. In the series, it serves as the hometown for the fictional peasant soldiers Tofi, Leofric, and Ordgar, whose names are actual Anglo-Saxon names from the period. Viewers may assume that the programme's title refers to "The Lord of the Rings" books, but Hardy chose "Middle Earth" because Anglo-Saxons frequently used the term to describe their world. He notes that J. R. R. Tolkien, an Oxford professor of Anglo-Saxon, used it, along with other Anglo-Saxon words, for the same reasons. 1066 The Battle for Middle Earth