Lithosphere-Asthenosphere boundary a thermal control of oceanic-lithosphere thickness. The continental lithosphere contains an ancient, stable part known as the craton. The LAB is particularly difficult to study in these regions and evidence suggests that the lithosphere within this old part of the continent is at it thickest and even appears to exhibit large variations in thickness beneath the cratons, thus supporting the theory that lithosphere thickness and LAB depth are age-dependent. Depths of the LAB beneath these regions (also known as shields and platforms) are estimated to be between 200 and 250 km deep. Beneath Phanerozoic continental crust, the LAB is roughly
What Is the Third Estate? What Is the Third Estate? What Is the Third Estate? () is a political pamphlet written in January 1789, shortly before the outbreak of the French Revolution, by the French thinker and clergyman Abbé Emmanuel Joseph Sieyès (1748–1836). The pamphlet was Sieyès' response to finance minister Jacques Necker's invitation for writers to state how they thought the Estates-General should be organized. In the pamphlet, Sieyès argues that the third estate – the common people of France – constituted a complete nation within itself and had no need of the "dead weight" of the two other orders, the first and second