Multiple trilobite fragments fossilized in the same rock
USNM_35225 and USNM_35227: Pictured are multiple trilobite fragments fossilized in the same rock. These are commonly known as hash beds. "Hash" is an indicator of a near-shore environment, where waves could hav... More
Multiple trilobite fragments fossilized in the same rock
USNM_35227 (pictured) and USNM_35225: Multiple trilobite fragments are fossilized in the same rock, these are commonly known as hash beds. "Hash" is an indicator of a near-shore environment, where waves could h... More
The outside of the Carnegie Exhibit Hall and the shuttle stop.
The Carnegie Exhibit Hall is named after Andrew Carnegie who in 1909 financed the early excavation of the Late Jurassic dinosaur fossils found here. It houses the wall of bones, which displays the fossilized ... More
National parks: Eusmilis - public domain image
Eusmilis, a nimravid that lived in the Turtle Cove about 29 million years ago
Cycle of Life - National Parks Gallery
And so, for 65 million years, the animals continued their journey, watching and waiting for the moon, as the cycle of life continues.
The volcanic Bidahochi Formation
The volcanic Bidahochi Formation caps and protects the Chinle Formation exposures along the Painted Desert Mesa at the north end of the park. The gap between the Bidahochi and Chinle Formations represents about... More
Horseshoe Crab’s Crown - National Parks Gallery
Horseshoe Crab’s Crown, a charming children’s book, traces the imagined re-creation journey of life on earth after the asteroid strike that wiped out the dinosaurs through 65 million years.
Horseshoe Crab's Crown - National Parks Gallery
Horseshoe Crab’s Crown, a charming children’s book, traces the imagined re-creation journey of life on earth after the asteroid strike that wiped out the dinosaurs through 65 million years.
Early salamander, Paleotaricha sp.
The early salamander species, Paleotaricha sp., was found in the Bridgecreek strata from about 33 million years ago.
The Goblin Bush / James Walter Chapman-Taylor collection
Public domain vintage photo from New Zealand archive, free to use, no copyright restrictions image - Picryl description
Our Allosaurus Fragilis skull. - Public domain natural history illustr...
This is a skull of an Allosaurus Fragilis, one of the prevalent meat eaters found in the Morrison Formation during the Late Jurassic period, about 150 million years ago. The Allosaurus was our second largest p... More
Excavations at the fossil bed, Hagerman Fossil Beds National Monument,...
The fossil beds at Hagerman National Monument are most famous for the abundance of fossilized and well-preserved Equus simplicidens skeletons, known as the Hagerman horse, Hagerman zebra or American zebra. Over... More
Excavations at the fossil bed, Hagerman Fossil Beds National Monument,...
Smithsonian excavation in 1930. The fossil beds at Hagerman National Monument are most famous for the abundance of fossilized and well-preserved Equus simplicidens skeletons, known as the Hagerman horse, Hagerm... More
![[Lynd Ward wood engraving block for plate #29 of Prelude to a million years]](https://cache.getarchive.net/Prod/thumb/cdn18/L3Bob3RvLzIwMTkvMTEvMjIvbHluZC13YXJkLXdvb2QtZW5ncmF2aW5nLWJsb2NrLWZvci1wbGF0ZS0yOS1vZi1wcmVsdWRlLXRvLWEtbWlsbGlvbi15ZWFycy0yNjBjN2UtMTAyNC5qcGc%3D/40/57/webp "[Lynd Ward wood engraving block for plate #29 of Prelude to a million years]")
[Lynd Ward wood engraving block for plate #29 of Prelude to a million ...
A wood block engraved by Lynd Ward to produce a print (no. 29) for his novel without text "Prelude to a Million Years." Exhibited: American Treasures of the Library of Congress, 2005.
Lariat Loop Scenic and Historic Byway - Dinosaur Ridge
The original finding aid described this photograph as: Original Caption: Over 300 dinosaur tracks on a 100 million-year-old tidal flat were uplifted when the Rocky Mountains rose 70 million years ago. The trac... More
Gold Belt Tour Scenic and Historic Byway - Petrified Tree Stumps
The original finding aid described this photograph as: Original Caption: Designated a National Monument in 1969, Florissant Fossil Beds preserves incredibly detailed insect and plant fossils dating to 34 milli... More
The fossil featured here is a leaf of a Macginitiea wyominensis, which...
YELL_92942: The fossil featured here is a leaf of a Macginitiea wyominensis, which is a member of the sycamore family. This particular plant existed during the Eocene, between 50 and 34 million years ago.
Yellowstone National Park, Articulate brachiopods
YELL-92017 and YELL-92024 (pictured here): Both the inarticulate (YELL-92017) and articulate brachiopods (YELL-92024) existed about 520 million years ago. The inarticulate was collected from the Park Shale, whi... More
Yellowstone National Park, Agnostid trilobite
YELL-165705: A small, Agnostid trilobite (YELL-165705) head is shown here. How did these little arthropods survive 500 million years ago? From their lack of eyes and poorly suited swimming body, scientists infe... More
Yellowstone National Park, Inarticulate brachiopods
YELL-92017 (pictured here) and YELL-92024: Both the inarticulate (YELL-92017) and articulate brachiopods (YELL-92024) existed about 520 million years ago. The inarticulate was collected from the Park Shale, wh... More
Multiple trilobite fragments fossilized in the same rock
USNM_35236: Charles D. Walcott, renowned invertebrate paleontologists, identified trilobite specimen Solenopleura? weedi (USNM 35236) from the Upper Cambrian (~500 million years ago) Pilgrim limestone in northw... More
Multiple trilobite fragments fossilized in the same rock
USNM_61523: Dated about 500 million years old and collected from the Pilgrim Limestone in Yellowstone National Park, is type trilobite Tricrepicephalus yellowstonensis (USNM 61523). This particular species is j... More
trilobite Blountia polita, Yellowstone National Park
USNM_96488: The trilobite Blountia polita (USNM 96488) (pictured) was discovered in the Middle Cambrian (~520 million years ago), Pilgrim Formation of Yellowstone National Park. As trilobites continued to evolv... More
Gibraltar - Strait of Gibraltar
STS039-151-193 (28 April-6 May 1991) --- The Strait of Gibraltar, the only outlet for the Mediterranean Sea, was photographed with a large format handheld camera by the STS-39 crew members. Scientists site evid... More
Prehistoric Yucatan Impact Crater: 'The infamous K-T impact event 65 m...
Prehistoric Yucatan Impact Crater: 'The infamous K-T impact event 65 million years ago (64.98 plus or minus 50,000 years), imagined here just as the bolide strikes, as seen by some high flying Pteranodons. Art... More
Andes Altiplano, South America. NASA public domain image colelction.
STS043-151-159 (2-11 August 1991) --- This photograph looks westward over the high plateau of the southern Peruvian Andes west and north of Lake Titicaca (not in field of view). Lima, Peru lies under the clouds... More
Cape Province, South Africa as seen from STS-58
STS058-77-083 (18 Oct-1 Nov 1993) --- In this scene of the south coast of Africa, Cape Agulhas, the southernmost point on the continent, appears as the leftmost cape. Viewed with the Earth's limb top left, clo... More
Ouachita Mountains, Oklahoma as seen from STS-58
STS058-91-058 (18 Oct-1 Nov 1993) --- In this unusually clear view, the Ouachita Mountains of southeastern Oklahoma are framed on the north by Lake Eufaula on the South Canadian River, and on the south by the R... More
Rhone River Valley & Lower Lake Geneva, Switzerland as seen from STS-6...
STS060-90-007 (3-11 Feb 1994) --- Parts of the Swiss Cantons of Vaud and Valois and the French province of Chablais are shown. These mountains were created in the last great mountain-building episode in Europe... More
Lake Geneva, France/Italy/Switzerland
STS068-243-076 (30 September-11 October 1994) --- Parts of the Swiss Cantons of Vaud and Valois, the French province of Chablis and parts of northwestern Italy are seen in this widely stretching image photograp... More
Turquoise Trail - Garden of the Gods Rock Formation
The original finding aid described this photograph as: Original Caption: Vertical beds of colorful sandstone and mudstore can be seen just a few feet off of Turquoise Trail. They are part of the Galisteo Found... More
Lariat Loop Scenic and Historic Byway - One Hundred Million Years at Y...
The original finding aid described this photograph as: Original Caption: An outdoor classroom adds interest as students learn of creatures walking this area eons ago. Status: Public domain. Digital Photograph... More
Earth observations taken from shuttle orbiter Columbia
STS073-727-045 (21 October 1995) --- Photographed by the astronauts aboard the Space Shuttle Columbia is this scene over Lake Powell. The lake was formed by the Glen Canyon Dam on the Colorado River. The vertic... More
Earth observations taken during the STS-77 mission
STS077-737-096 (19-29 May 1996) --- The Palmer River emerging from the left corner of the photograph separates the Gardener Range to the right from the James Ranges on the left. To the bottom and off the photo... More
Earth observations taken during STS-77 mission
STS077-732-093 (19-29 May 1996) --- This high oblique perspective from the Space Shuttle Endeavour shows the Dead Sea Rift Valley and the surrounding deserts. North is to the right side of the frame. The vege... More
View of the ODS in the Atlantis payload bay prior to docking
STS079-824-081 (16-26 Sept. 1996) --- In this 70mm frame from the space shuttle Atlantis, the Jordan River Valley can be traced as it separates Lebanon, Palestine and Israel on the west, from Syria and Jordan o... More
Quintuplet Cluster. NASA public domain image colelction.
(September 16, 1997) Penetrating 25,000 light-years of obscuring dust and myriad stars, NASA's Hubble Space Telescope has provided the clearest view yet of one of the largest young clusters of stars inside our ... More
Earth observations during STS-89
STS089-743-004 (22-31 Jan. 1998) --- This picture showing Auckland Island, New Zealand was photographed with a 70mm handheld camera from the Earth-orbiting space shuttle Endeavour. A spectacular occurrence of ... More
Earth observations during STS-89 mission
STS089-706-068 (22-31 Jan. 1998) --- This nadir view of the southern Cape District of South Africa was photographed with a 70mm handheld camera from the Earth-orbiting space shuttle Endeavour. Prominent landma... More
Earth observations during STS-89
STS089-742-014 (22-31 Jan. 1998) --- This near-nadir picture of the central Andes, showing Santiago and other parts of Chile and Argentina, was photographed with a 70mm handheld camera from the Earth-orbiting s... More
Preliminary Excavations in 1999
In October of 1999, researchers from the University of Texas at Dallas, working under a scientific research permit, discovered the 27-foot long section of dinosaur neck in Big Bend National Park. The fossil is ... More
Rhyolite Rocks, Chiricahua national monument
Rhyolite Canyon Tuff is a volcanic rock formed from a massive volcanic eruption 27 million years ago. It is compressed ash.
Passive Continental Margin (Ancient)—Grand Canyon National Park, Arizo...
The layering in the upper part of the canyon formed over 200 million years ago, when the Colorado Plateau region was part of an ancient passive continental margin.
Cinder Cone and Lava Flow - Public Domain image, National Parks Galler...
Cinder Cone National Natural Landmark: Thirty-two cinder cones surrounded by a sea of hardened lava flows that began erupting into existence 7.6 million years ago. Lava last flowed just 10,000 years ago.
Kolkheti National Park 08: Wetland Kolkhic Forests
Kolkheti National Park: Relict Wetland Kolkhic Forests. The Kolkheti lowlands include rare species (relics) typical of the tropical and subtropical vegetation that stretched across the Eurasian continent approx... More
Palmites sp., approximately 2 meters long
The presence of palm fossils indicate a much warmer and wetter climate 52 million years ago, similar to the Gulf coast states today.
Petrified Forest National Park Rainbow Forest Museum Late Triassic Mur...
Petrified Forest National Park Rainbow Forest Museum Late Triassic Mural, painted by Victor Leshyk, shows what this area looked like over 200 million years ago.
An overview picture of the Morrison Mural.
The Morrison Mural shows what we know about the Morrison environment, based on years of research by paleontologists and geologists. In the upper left portion of the photo is a cast of an Allosaurus fragilis, w... More
Cathedral Valley, Capitol Reef National Park, 2012.
Glass Mountain (foreground) is made of large gypsum (selenite) crystals deposited when seawater evaporated around 165 million years ago. After deposition and burial under rock layers, the gypsum began to move s... More
West Elk Breccia, Curecanti National Recreation Area, 2013.
The West Elk Breccia is formed from a huge volcanic lahar (i.e., volcanic flow) of ash and debris that spewed from violent, pyroclastic eruptions (i.e., spitting/fountaining lava is thrown into the air along wi... More
Bobcat, Black Canyon of the Gunnison National Park, 2013.
Bobcats are solitary and not often seen during the day. The bobcat (Lynx rufus) is a North American mammal that appeared around 1.8 million years ago. Twelve subspecies are currently recognized. This adaptable ... More
Twisted and folded rock near the Quarry Visitor Center
When the Rocky Mountains rose approximately 50-60 million years ago, it both folded and twisted these rock layers. With weathering, they became what you see today. This is an end of summer picture, taken late... More
Mesocyon coryphaeus by Artist in Residence Morgan Turner
A scientific illustration of Mesocyon coryphaeus was drawn by Artist in Residence Morgan Turner. Mesocyon coryphaeus was a short faced canid about the size of a coyote living around 34-24 million years ago.
Hoodoos, Bryce Canyon National Park, 2015.
Hoodoos are tall, skinny spires of rock that protrude from the bottom of arid basins and 'broken' lands. Formed in sedimentary rock, the shape of a particular hoodoo is affected by the erosional patterns of alt... More
Horseshoe crabs (Limulidae) returning to breed, Fire Island National S...
Horseshoe crabs originated around 450 million years ago and are considered 'living fossils', meaning they are similar to related species only known from fossils. In recent years, they have experienced a populat... More
Bobcat, Shenandoah National Park, 2015.
Bobcats are solitary and not often seen during the day. The bobcat (Lynx rufus) is a North American mammal that appeared around 1.8 million years ago. Twelve subspecies are currently recognized. This adaptable ... More
Elba Quartzite of Green Hill, City of Rocks National Reserve, 2015.
The Elba Quartzite was formed after the Green Creek Complex. It is one of the most distinctive geologic units of the Albion Mountains - very light in color and extremely weather-resistant (because of the high q... More
Fossils in Jurassic limestone, National Mall and Memorial Parks, 2015.
These fossil ammonites and belemnites in the Jurassic limestone from Bavaria, Germany dates back to 150 million years ago. Witness these fossils on the floor of the bookstore when visiting the Martin Luther Kin... More
Horseshoe crabs (Limulidae), Fire Island National Seashore, 2015.
Horseshoe crabs originated around 450 million years ago and are considered 'living fossils', meaning they are similar to related species only known from fossils. In recent years, they have experienced a populat... More
Hagerman Fossil Beds, Hagerman Fossil Beds National Monument, 2015.
Pictured: Hagerman Fossil Beds as seen from the Snake River. This area contains fossils of species alive during the Pliocene Epoch, 3-4 million years ago. See what not-so-ancient life was like with almost 150 t... More
C. megalodon fossil tooth. PORE 8467
Fossil tooth of C. megalodon, crown and root. One of the largest vertebrate predators of the sea ever to have lived. The fossil record suggests these animals may have grown to at least 59 feet (18 meters) long.... More
View of the Killpecker Sand Dunes in Wyoming's Red Desert, north of Ro...
Title, date and keywords based on information provided by the photographer. Credit line: Gates Frontiers Fund Wyoming Collection within the Carol M. Highsmith Archive, Library of Congress, Prints and Photograph... More
View of the Killpecker Sand Dunes in Wyoming's Red Desert, north of Ro...
Title, date and keywords based on information provided by the photographer. Credit line: Gates Frontiers Fund Wyoming Collection within the Carol M. Highsmith Archive, Library of Congress, Prints and Photograph... More
View of the Killpecker Sand Dunes in Wyoming's Red Desert, north of Ro...
Title, date and keywords based on information provided by the photographer. Credit line: Gates Frontiers Fund Wyoming Collection within the Carol M. Highsmith Archive, Library of Congress, Prints and Photograph... More
View of the Killpecker Sand Dunes in Wyoming's Red Desert, north of Ro...
Title, date and keywords based on information provided by the photographer. Credit line: Gates Frontiers Fund Wyoming Collection within the Carol M. Highsmith Archive, Library of Congress, Prints and Photograph... More
View of the Killpecker Sand Dunes in Wyoming's Red Desert, north of Ro...
Title, date and keywords based on information provided by the photographer. Credit line: Gates Frontiers Fund Wyoming Collection within the Carol M. Highsmith Archive, Library of Congress, Prints and Photograph... More
Scene along the Bighorn River at the north end of the Wind River Canyo...
Title, date and keywords based on information provided by the photographer. Credit line: Gates Frontiers Fund Wyoming Collection within the Carol M. Highsmith Archive, Library of Congress, Prints and Photograph... More
View of the Killpecker Sand Dunes in Wyoming's Red Desert, north of Ro...
Title, date and keywords based on information provided by the photographer. Credit line: Gates Frontiers Fund Wyoming Collection within the Carol M. Highsmith Archive, Library of Congress, Prints and Photograph... More
Scene along the Bighorn River at the north end of the Wind River Canyo...
Title, date and keywords based on information provided by the photographer. Credit line: Gates Frontiers Fund Wyoming Collection within the Carol M. Highsmith Archive, Library of Congress, Prints and Photograph... More
Visitor Center diorama, Agate Fossil Beds National Monument, 2016.
Reconstructed skeletons of Miocene age mammals aid in understanding the early 1900s excavations. Mammals found at Agate Fossil Beds National Monument date from the early Miocene Epoch (19-21 million years ago).... More
Scene along the Bighorn River at the north end of the Wind River Canyo...
Title, date and keywords based on information provided by the photographer. Credit line: Gates Frontiers Fund Wyoming Collection within the Carol M. Highsmith Archive, Library of Congress, Prints and Photograph... More
Transform Plate Boundaries—Pinnacles National Park, California
Located near the San Andreas Fault along the boundary of the Pacific Plate and the North American Plate, is an excellent example of tectonic plate movement. Some 23 million years ago multiple volcanoes erupted,... More
Growth of the Pacific Northwest
200 million years ago the coastline of the Pacific Northwest was near Idaho’s western border. There was no Oregon and Washington!
Tectonic Evolution of the Southern Appalachian Mountains—300 Million Y...
300 Million Years Ago—Iapetus Ocean Completely Closes. The Southern Appalachians develop as the African portion of Gondwanaland crashes in, forming the supercontinent of Pangea.
West Coast Tectonic Evolution—20 Million Years Ago
As the mid-ocean ridge separating the Farallon and Pacific Plates entered the subduction zone, the Farallon Plate separated into the Juan de Fuca and Cocos Plates. A transform plate boundary developed where the... More
Tectonic Development of the Appalachian—Ouachita—Marathon Mountain Ran...
500 Million Years Ago—Iapetus Ocean Opens. Land that will later become Florida is part of Africa. The Yucatan Peninsula and Cuba may have been on the north side of South America.
Continental Rift: Topography, Earthquakes and Volcanism
The Basin and Range topography develops over a few million years as fault lines move gradually, or more abruptly during tens of thousands of earthquakes. The colder upper crust cracks and breaks along faults (l... More
Tectonic Development of the Appalachian—Ouachita—Marathon Mountain Ran...
250 Million Years Ago—Iapetus Ocean Closes. Pangea forms as the continents collide. The Appalachians are part of a larger zone of continental collision that includes the Marathon and Ouachita mountains in the s... More
![West Coast Tectonic Evolution—40 Million Years Ago [1 of 3]](https://cache.getarchive.net/Prod/thumb/cdn2/L3Bob3RvLzIwMTkvMDEvMDEvd2VzdC1jb2FzdC10ZWN0b25pYy1ldm9sdXRpb240MC1taWxsaW9uLXllYXJzLWFnby0xLW9mLTMtOTZhMzRmLTEwMjQuanBn/40/41/webp "West Coast Tectonic Evolution—40 Million Years Ago [1 of 3]")
West Coast Tectonic Evolution—40 Million Years Ago [1 of 3]
Forty million years ago, a large tectonic plate, known as the Farallon Plate, was between the Pacific and North American plates. Subduction of the Farallon Plate beneath the entire West Coast created a line of ... More
Emperor Hotspot Track—Ocean Floor
The topography and bathymetry (underwater topography) of the northern Pacific Ocean reflect the movement of the Pacific Plate over the Hawaiian Hotspot. Prior to 42 million years ago, the Pacific Plate was movi... More
Growth of the Pacific Northwest—Cross-section Illustration
Sometimes a terrane crashes in and clogs the subduction zone. A new subduction zone develops farther west. The Cascadia Subduction Zone is just the latest of several subduction zones that developed in the weste... More
![West Coast Tectonic Evolution—20 Million Years Ago [2 of 3]](https://cache.getarchive.net/Prod/thumb/cdn2/L3Bob3RvLzIwMTkvMDEvMDEvd2VzdC1jb2FzdC10ZWN0b25pYy1ldm9sdXRpb24yMC1taWxsaW9uLXllYXJzLWFnby0yLW9mLTMtMDdlMjc3LTEwMjQuanBn/40/41/webp "West Coast Tectonic Evolution—20 Million Years Ago [2 of 3]")
West Coast Tectonic Evolution—20 Million Years Ago [2 of 3]
As the mid-ocean ridge separating the Farallon and Pacific Plates entered the subduction zone, the Farallon Plate separated into the Juan de Fuca and Cocos Plates. A transform plate boundary developed where the... More
West Coast Tectonic Evolution—40 Million Years Ago
Forty million years ago, a large tectonic plate, known as the Farallon Plate, was between the Pacific and North American plates. Subduction of the Farallon Plate beneath the entire West Coast created a line of ... More
Western U. S. Terrane Accretion
The yellow and green shows material added (accreted) to the western edge of North America during the past 200 million years. The North American Craton refers to the continent that existed prior to that time. Ro... More
Yellowstone Hotspot Track—Columbia Plateau, Oregon
Columns of basalt represent vast outpourings of fluid lava that covered large portions of Oregon, Washington, and Idaho as the hotspot surfaced 17 million years ago.
Paleogeographic Globe of the Late Triassic—217 Million Years Ago
The paleogeographic map shows that, during the Late Triassic Epoch, North America straddled the equator and Petrified Forest National Park (white dot on red map of Arizona) was at about 4° north latitude.
Tectonic Evolution of the Southern Appalachian Mountains—500 Million Y...
500 Million Years Ago—Iapetus Ocean Opens. Continental blocks destined to become North America and Gondwanaland drift apart. The eastern edge of ancient North America developed into a passive continental margin... More
Emperor Hotspot Track - National Parks Gallery
The topography and bathymetry (underwater topography) of the northern Pacific Ocean reflect the movement of the Pacific Plate over the Hawaiian Hotspot. Prior to 42 million years ago, the Pacific Plate was movi... More
Tourist Attraction - Ouachita Mountains, Arkansas
The sandstone, shale and chert layers are part of a thick pile of sediments that were deformed and uplifted as Gondwanaland collided with the southern edge of ancient North America 280 million years ago.
Tectonic Evolution of the Southern Appalachian Mountains—750 Million Y...
750 Million Years Ago—Old Continent Rips Apart. The long mountain ranges and rift valleys were similar to those forming today in East Africa and the Basin and Range Province.
Southern Alaska Subduction Zone
Plate convergence that built Alaska outward as a series of accreted terranes during the past 200 million years continues today. Kenai Fjords has oceanic sedimentary layers that have been metamorphosed, uplifted... More
Tectonic Evolution of the Brooks Range—200 Million Years Ago
200 Million Years Ago—Ocean separating northern Alaska and a continental fragment begins to close.
Tectonic Development of the Appalachian—Ouachita—Marathon Mountain Ran...
"Today"—Atlantic Ocean and Gulf of Mexico Open. The modern oceans originated about 200 million years ago when Europe, Africa and South America ripped away from North America. Fragments of the collision zone mou... More
Collisional Mountains—Shenandoah National Park, Virginia.
Shenandoah National Park, Virginia. The rugged Appalachian Mountains are the eroded remnants of much higher mountains that formed as continents collided 300 million years ago.
Petrified Forest Badlands - National Parks Gallery
Badlands area in Petrified Forest National Park. The Amazon-like landscape has evolved over more that 200 million years from a green tropical forest to red Painted Desert. Layers of the Late Triassic Chinle For... More
Hotspot Sites in the National Park System
The landscapes of National Park System sites along hotspot tracks differ depending on if the plate riding over the hotspot is capped by thin oceanic or thick continental crust. Oceanic Hotspots: Sites in Hawaii... More
The Landscapes of Denali National Park Reveal Different Accreted Terra...
Pillow Basalt—The blobs of lava formed as fluid lava poured out on an ancient seafloor about 200 million years ago. They have since been accreted to North America and uplifted as part of the McKinley Terrane. T... More
Tectonic Development of the Atlantic Ocean and Gulf of Mexico (1 of 2)
The supercontinent of Pangea formed 300 million years ago as an ancient ocean closed. A chain of mountains formed as the continents collided, including the Marathon, Ouachita and Appalachian mountians in the Un... More
Tectonic Evolution of the Southern Appalachian Mountains—400 Million Y...
400 Million Years Ago—Iapetus Ocean Narrows during Subduction. Oceanic sediments and volcanic islands were at times added to the edge of North America.
NPS Sites in Alaska - Public Domain image, National Parks Gallery
The terrane accretion that built Alaska onto the rest of North America over the past 200 million years includes the continental collision that formed the Brooks Range in the northern part of the state. The Nort... More