S: National Parks Rosemary
2: Big bang: ~14 billion years Solar system: 4.7 billion years Earth: 4.5 billion years Life exploded: ~500 million years Pangaea: - 200 million years Animals and dinosaurs: ~200 million years Humans go back only ~1 million years
3: Grand Canyon - Lowest step of the Grand Staircase Zion is in the middle Bryce is the highest step (and the youngest rocks) Entire region was part of an inland sea that caused all of the sedimentary layers, dunes and fossils
4: Grand Canyon Oldest rocks at bottom: 1.8 billion years old Base of 5-6 mile high mountains that eroded (weight caused the metamorphic rocks, schists and gneiss) By 1.2 billion years ago, mountains eroded away For next ~1 billion years, inland sea in and out ~8 times - leaving behind many layers of sedimentary rock with fossils Top layer, Kaibab limestone, is 270 million years old - rocks above have eroded 75 - 50 million years ago: Laramide Orogeny caused by collision of North American and Pacific plates created Rocky Mountains - caused ocean to drain 10 million years ago, Colorado Plateau lifted up about 2 miles with very little damage to the earth on the Plateau other than lifting it 5 million years ago, river course changed to west and rapidly cut canyon South rim is about 7,500 ft above sea level and North Rim is about 1,000 ft higher
9: Fossils on Kaibab layer from sea
11: Glen Canyon and Lake Powell Navajo Sandstone - former sand dunes ~200 million years ago (Jurassic), this area was a large sand dune (sand sea or erg) 10 million years ago, Colorado Plateau uplift caused last sea to retreat and left dune behind Water and minerals combined with sand to create the sandstone Eventually, covered but then exposed again due to erosion Canyon carved over last 5 million years Desert Varnish - mineral rich desert dust, minerals in the rocks and water from the rocks causes reaction
13: Anasazi carvings ~800 years old | Arch from fallen rocks
14: Fault rock and cold water
16: Bryce Canyon Not cut by a river so technically not a canyon 8-9,000 feet above sea level Freezes and thaws ~250 days per year - causing erosion at rate of 1-2 feet per 100 years Rocks at Bryce began to form ~200 million years ago (Jurassic and Cretaceous) over a 60 million year period of seas coming in and out of the area ~66-40 million years ago, iron rich limestone from rivers formed during Laramide Orogeny formed the Claron Formation from which the Hoodoos are carved (hence, the Pink Cliffs) 10 million years ago, Colorado Plateau uplift - erosion cycle accelerated Rocks erode at varying rates and thus the various shapes and figures
22: ~ 200 million years ago (Jurassic) deposition of layers began. The sand layer was about 2,000 feet thick at Zion. At this time, there was one super-continent, Pangaea, and Zion was close to the equator. Shallow sea caused much of the sediments and Laramide Orogeny and Colorado Plateau uplift caused receding of sea and rapid down cutting by rivers. Navajo sandstone created by hardening ("fossilized") dunes and it is hard and resistant to erosion. Other formations less resistant - hence the varying width of the canyon. Virgin River cut the canyon over the past 2 million years. Canyon walls are 2,000 feet high. Red color from iron and the whitish colors are from the effect of acidic groundwater bleaching it. Desert varnish from interaction of iron and the water seeping in the rocks and from waterfalls.
26: Quick thunderstorm results in rapid and muddy flow that cuts the river deeper
27: North Rim
32: Staircase - Vermillion and White Cliffs from just outside North Rim
34: First park set aside by Federal Government during Civil War Batholith - intrusive igneous rock - granite formed underground Formed ~200 to 80 million years ago - magma flow hardened 6 miles underground Estimated size of batholith: 350 miles x 65 miles With erosion, rock becomes uncovered and as top sediments disappear, pressure releases and cracks form in the granite 10 million years ago, uplift of Sierra Nevada mountains - increased tilt of Merced River that caused canyon cutting and erosion Glaciers ~ 1 million year ago covered Yosemite with about 4,000 feet of ice and sculpted the valley and many of the rocks
36: Merced River along Highway 140
38: Half Dome carved away by glacier | Yosemite Falls: upper and lower drop 2,435 feet. #6 in world
40: El Capitan | Giant Sequoias in Mariposa Grove ~3,000 years old
42: Moraine - last glacier melted here | Half Dome | Rock slide closed road
44: 250- 65 million years ago, area covered by shallow sea (from Gulf of Mexico to Canada Pierre shale - oldest layer of Badlands was bottom of Sea and formed after sea receded 65 mya Sediments from Black Hills erosion blown into this area Laramide Orogeny caused uplift and sea to recede Erosion from wind, rain and rivers flowing from Black Hills have caused the landscape. Most of Badlands created in last 500,000 years Eroding a rate of 1 inch per year - in 500,000 years, they will be gone
45: Wall Drug at edge of Badlands "Wall"
46: Sedimentary layers from ancient sea, volcanoes to west. As sea drained with uplift of Rockies, sea bed reacted with air to form yellow color.
47: Mount Rushmore
48: 5,725 feet above sea level Part of Harney Peak - granite batholith formed underground ~1.6 billion years ago; covered by inland sea. Batholith forced up into Mica Schists - leaves veins in the granite seen on the faces of the sculptures. Granite slow to erode (1 inch per 10,000 years) Laramide Orogeny created Black Hills 70 million years ago. Once they were 15,000 feet tall. The granite was first exposed about 50 million years ago Heads of carvings are 60 feet tall - original plan was to have bodies as well but ran out of funding Four presidents symbolized trials and tribulations of first 150 years of US history.
51: Formed 50 million years ago by underground volcano Erosion exposed it 1-2 million years ago 867 feet tall | Devil's Tower
54: Shell Canyon named for sea shells found from former sea. Canyon rocks are about 2.9 billion years old.
55: Shell monocline: caused by Laramide Orogeny 70 million years ago. As west moving North America plate moved, it folded down to one side. Exposed by erosion.
56: Red shale and siltstone from Triassic (200 mya); exposed by river down cutting.
58: Yellowstone Sitting on top of huge caldera (30 x 45 miles) 3 major eruptions: 2 mya; 1.2mya; and 640,000 years ago Magma chamber is ~5 miles below surface Oldest rocks in park are ~2.7 billion years old 570 - 75 million years ago, inland sea covered much of current US; sedimentary rocks in park are from this era. Fossil evidence shows sea advanced/retreated ~12 times 75 to 50 million years ago: Laramide Orogeny caused by North America plate overriding Pacific plate. Typically, mountains form along coast but due to shallow angle, plate slid far inland with hot spot under current location of park. 55-50 mya: volcanoes create igneous rocks 50-40mya: Absaroka volcanoes to east buried area 40-10mya: erosion wiped away a lot of the past geology 10mya: uplift - Teton mountains created 3 to 2 mya: magma builds up to eruptions
62: Hayden Valley - Elk killed with grizzlies in the river
63: Grand Canyon of Yellowstone ~1000 feet deep. Yellow is caused by iron in the rocks | Yellowstone upper and lower falls: upper is 108 feet and lower is 308 feet (2x Niagara)
64: Mammoth Hot Springs and Liberty Cap
65: Old Faithful - erupts every 60 - 90 minutes for about 3 - 5 minutes
66: Continental Divide: North - South division with all water to east draining to Atlantic and to the west into the Pacific
68: Brink of upper and lower falls: on lava flows from 600,000 years ago. The falls occur where weak rocks eroded away and the river down cuts
69: Red dots show caldera border | As plate moves to west, hot spot does not move | Volcanic tuff rocks | Grey wolf