Ochoco Mountains made of rocks from the Permian, Triassic, and Jurassic periods (300 to 200 million years old) that were transported by the Pacific Plate and accreted in the late Mesozoic era (about 100 million years ago) as part of a vast shallow sea, then slowly uplifted by volcanic eruptions during the Eocene epoch (50 to 37 million years ago) to form the Clarno Formation. From 37 to 17 million years ago, eruptions in the western Cascade Range spread ash across eastern Oregon, forming the John Day Formation. From 17 to 14 million years ago, major volcanic eruptions covered much of the
Geology of the Seychelles 85 million years ago as the Mascarene ocean basin formed. The Deccan Traps hotspot, which poured out immense basalt flows in India 65 million years ago and ultimately formed islands such as Mauritius and Réunion, isolated Seychelles. The microcontinent was confined between northern Madagascar and western India until the Late Cretaceous and evolved during the Cenozoic through a process of rift and drift tectonics. The microcontinent was uplifted, eroded and impacted by volcanic eruptions. In the early Cenozoic, around 63 million years ago, alkaline plutonic and volcanic rocks emplaced to become the Silhouette and North islands. Seychelles sources most of