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
Core-and-pod kind of large and wide tree, with many “branches,” or pods, off the main “trunk,” or core. Core-and-pod Core-and-pod design is a network design that uses individual pods that hang off the core layer as atomic units. Within the pod, there may be only a single access layer or a “leaf and spine” network in the pod. The routed core layer serves as a fast and simple way to connect many generations of pods to each other. When the “leaf and spine” network is used within the pod, the core layer can be referred to as the “spine of spines,”