Labels:text | black and white | font | number | screenshot | document OCR: Era Period Epoch and Events Quaternary Holocene Age in years Normal faults of the: Intermountain Seismic Belt in the Basin and Range Province Deposition of blanket of loess on much of the area south and east of Pocatello (Recent) 12,000- Eruption of basalt lava flows at Craters of the Moon, the Great Rift, and Hell's Half Acre north of Blackfoot Pleistocene Lake Bonneville Flood (14,500 years ago) with retreat to Provo Shoreline until 11,000 years Late Wisconsin glaciation and most recent rise of Lake Bonneville (30,000 to 12,000 years ago) Formation of the ancestral American Falls Lake, visited by giant land mammals (75,000 years ago) Eruption of tuff cones at Menan Buttes (about 70,000 years ago) Eruption of Basalt of Portneuf Valley (600,000 years) causes diversion of Bear River, formation of Lake Thatcher and cutting of Oneida Narrows Rhyolite domes formed at Big Southern Butte, East and Middle Buttes Eruption of Snake River Group of basalt lava on the Snake River Plain and in the Blackfoot Lava Field Catastrophic eruption of rhyolite ash flows of Yellowstone Volcanics (2 Ma, 1.2 Ma, and 600,000 years) 2 Ma Multiple glacial and interglacial intervals cause lakes to form in several lowlands in Idaho Tertiary Neogene Pliocene Formation of Lake Idaho on the western Snake River Plain. Primitive horses buried near Hagerman. Superposed streams cot Portneuf Narrows, Garden Creek Gap, Bear River Canyon at Lava Hot Springs 5 Ma Basin and Range faulting and Snake River Plain volcanism continues; Basaltic eruptions at Massacre Rocks. Miocene Teton Mountains start to rise (5 to 10 m.y. ago) Volcanic ash of Salt Lake and Starlight Formations deposited in valleys south of the Snake River Plain Series of rhyolite caldera eruptions migrate northeastward along the Snake River Plain, from the Bruneau- Jarbidge center in SW Idaho, to the Twin Falls area (Idavada volcanics, to the Pocatello area (lava on Howard Mountain, to the Rexburg Caldera (Heise volcanic field, 6 Ma). About 17 m.y. ago Yellowstone-Snake River Plain Hot Spot originates in southeast Oregon 24 Ma Basin and Range faulting begins generally moving outward in time from central Nevada Paleogene Oligocene Generally Idaho is a topographic plateau; few Oligocene sedimentary rocks remain. 37 Ma- Intrusion of Almo Pluton at what is now the Silent City of Rocks and final uplift of core complexes. Eocene Eruption of Challis Volcanic Group Formation of gold-bearing mineral deposits of the Trans-Challis fault system Intrusion of granitic stocks in Sawtooth Range, Boulder Mountains, and elsewhere in central Idaho Metamorphism and intrusion in Pioneer Mountains and Albion Mountains core complexes 58 Ma Deposition of fluvial Wasatch Formation in SE Idaho and lacustrine Green River Formation in SW Wyoming Paleocene Major uplift of Laramide basement blocks in northwest Wyoming (Wind River, Gros Ventre, Ancestral Teton Ranges), with continued thrusting in thrust belt 66 Ma- Major extinction event, withdrawal in interior seaway and drop in worldwide sea level Mesozoic Cretaceous Formation of rich silver-lead-zinc veins near Hailey and Bellevue Intrusion and mineralization of the Idaho batholith (mainly Late Cretaceous) Deposition of Gannett Group in foreland basin that passed eastward into a shallow sea Peak of thrust faulting and folding of the Idaho-Wyoming thrust belt Metamorphism in core complexes of Pioneer and Albion Mountains in hinterland of Sevier orogenic belt Jurassic 144 Ma Subsidence in the foreland basin east of the Sevier orogenic belt; deposition of sandstones in E Idaho 208 Ma Formation of Sevier orogenic belt, with magmatic belt on the west and fold-thrust belt to the east Triassic Establishment of thick carbonate bank of the Thaynes Formation with shallow evaporite lagoon to the east 245 Ma Deposition of continental redbeds in thrust belt, last vestige of the Ancestral Rockies Paleozoic Permian Phosphate-rich Phosphoria Formation deposited in biologically productive shallow sea -286 Ma Sun Valley and Oquinh basins continue; these are last major marine deposits as sea level falls in Triassic Carboniferous Pennsylvanian Sun Valley and Oquirth Groups deposited in basin inboard of mountainous areas to the south (Ancestral - 320 Ma Rockies) and west (reactivated Antler or western oceanic highland) Mississippian Carbonate bank of the Madison Group covers much of Northern Rockies Deep water turbidites of Copper Basin Formation and McGowan Creek Formation deposited in basin east 360 Ma of the uplifted Antler orogenic belt Devonian 408 Ma End of passive western American continental margin. Formation of silver-lead-zinc in Milligen Formation. Silurian 438 Ma Formation of regional carbonate bank of Laketown Dolomite Ordovician Deposition of the Swan Peak and Kinnikinic Quartzites and Fish Haven Dolomite 505 Ma Intrusion of granitic plutons in the Beaverhead and Salmon River Mountains Cambrian Early complex life thrives in carbonate banks now seen in Cambrian limestones. Carbonate was formed during rapid crustal subsidence after separation of North America from Antarctica or Australia 540 Ma Major encroachment of the paleo-Pacific ocean over western U.S. (transgression of the shoreline) Pre- Proterozoic Late First complex multicellular life evolves in latest Proterozoic time cambrian Deposition of Brigham Group of gravelly sandstones and siltstones in braided streams and shallow seas -1000 Ma Glaciation, continental rifting and basaltic volcanism recorded in the Pocatello Formation Middle Formation of huge, shallow water intracratonic basin of the Belt Supergroup in western Montana and east- central Idaho (rocks are called Lemhi Group in Idaho) 1600 Ma Formation of mineral deposits of the Cobalt and Blackbird areas Early Deposition of the Elba Quartzite in the Albion Mountains and Wasatch Range Metamorphism of crust in Pioneer Mountains 2500 Ma Intrusion of mafic dikes in the Teton Range about 1500 Ma Archean Intrusion and high-grade metamorphism in core of Albion Mountains and Teton Range
