A terrane is a group of rocks that share a similar origin and geologic history. Much of northeast North America is made from terranes. Over numerous hundred million years, plate tectonic forces welded different terranes on to the east coast of Laurentia, the ancient paleocontinent that comprises the core of North America.
The land that would become Avalonia very first formed as a chain of volcanoes off the western coast of the supercontinent Gondwana about 600 million years earlier. About 465 million years earlier, the land rifted away from Gondwana. It began inching west throughout the proto-Atlantic Ocean, driven by plate tectonic forces.
Between about 425 million and 380 million years ago, Avalonia hit Laurentia and required up a range of mountains along the suture. This accident was an early part of the Acadian Orogeny, the 2nd major mountain-building stage of the Appalachian Mountains. In the U.K., it is called the Caledonian Orogeny.
The 3rd phase of Appalachian mountain-building, the Alleghanian Orogeny, happened around 350 million to 250 million years back. During this stage, Avalonia, now connected to North America, was captured in the center as the continents assembled, closing the proto-Atlantic Ocean and forming the supercontinent Pangaea.
Avalonia was rifted apart when Pangaea started to break up about 200 million years earlier. Pieces of it can now be found in North America, Europe, and Africa. Continued rifting apart North America and Europe and opened the modern-day Atlantic Ocean– setting the stage for the historical events to follow millions of years later on.
Astronaut photo ISS065-E-93706 of Plymouth, U.K., was obtained on June 8, 2021, with a Nikon D4 digital camera using an 1150 millimeter lens. Astronaut picture ISS065-E-124634 of Plymouth, MA, was acquired on June 18, 2021, with a Nikon D4 digital electronic camera using a 50 millimeter lens. Both images were provided by the ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit, Johnson Space Center, and were taken by a member of the Expedition 65 team. These images have actually been cropped and enhanced to enhance contrast, and lens artifacts have been gotten rid of. The International Space Station Program supports the laboratory as part of the ISS National Lab to assist astronauts take images of Earth that will be of the best worth to researchers and the public, and to make those images easily available on the Internet.
June 8, 2021
June 18, 2021
This fall marks the 400th anniversary of a 1621 event of members of the Wampanoag Nation and European colonists near Plymouth, Massachusetts. Historians still debate the specific circumstances of the event, however the story motivated the modern-day American custom of Thanksgiving, which was designated a legal holiday by Abraham Lincoln in 1863. For numerous Native Americans, however, it is not a day of thanksgiving, however of mourning.
The colonists arrived on Cape Cod in November 1620 after crossing the Atlantic on the Mayflower from Plymouth in southwest England. After exploring parts of the Cape and making their first encounters with the Wampanoag, the colonists sailed across Cape Cod Bay, landed near an abandoned Wampanoag settlement referred to as Patuxet, and established the Plymouth Colony.
Plymouth, Massachusetts, and Plymouth, England, are revealed above in photos shot by astronauts from the International Space Station. These 2 similarly named locations also share an even older geological connection. During the Paleozoic Era, a number of hundred million years ago, the land that would end up being southeastern Massachusetts and southwestern England were part of the exact same microcontinent– Avalonia, or the Avalon terrane.
The land that would become Avalonia first formed as a chain of volcanoes off the western coast of the supercontinent Gondwana about 600 million years back. About 465 million years ago, the land rifted away from Gondwana. Between about 425 million and 380 million years ago, Avalonia collided with Laurentia and required up a mountain range along the suture. When Pangaea began to break up about 200 million years earlier, Avalonia was rifted apart.
By Sara E. Pratt, NASA Earth Observatory
November 25, 2021
During the Paleozoic Era, several hundred million years back, the land that would end up being southeastern Massachusetts and southwestern England were part of the exact same microcontinent– Avalonia, or the Avalon terrane.
