Structure of the Earth obducted onto the continental crust and preserved as ophiolite sequences. Many rocks now making up Earth's crust formed less than 100 million (1) years ago; however, the oldest known mineral grains are about 4.4 billion (4.4) years old, indicating that Earth has had a solid crust for at least 4.4 billion years. Earth's mantle extends to a depth of 2,890 km, making it the thickest layer of Earth. The mantle is divided into upper and lower mantle. The upper and lower mantle are separated by the transition zone. The lowest part of the mantle next to the core-mantle boundary is
Salt crust of the salt crust method with the French "en papillote" style. In a Muslim cookbook originating from the thirteenth century, a layer of salt is placed on a new terracotta tile as a base and the fish is placed on top and another layer of salt is added on, then finally being placed in an oven. The Portuguese also have a history of drying and salting fish with their famous dish, Bacalhau, as before refrigeration, food needed to preserve to extend their expiry date. The fish used, cod, even caused battles between countries resulting in an Icelandic victory. Callaloo was