The 366 daily episodes in 2014 were chronological snapshots of earth history, beginning with the Precambrian in January and on to the Cenozoic in December. You can find them all in the index in the right sidebar. In 2015, the daily episodes for each month were assembled into monthly packages (link in index at right), and a few new episodes were posted from 2015-18. Beginning in May 2019, I'm adding short entries to the blog (not as podcast episodes, at least not for now, sorry!) mostly taken from the Facebook Page posts. Thanks for your interest!

Saturday, May 11, 2019

Timan-Pechora Basin

This is part of the magnetic map of the former Soviet Union. It reveals three continental blocks and their amalgamation to form part of Eurasia. The Siberian Craton (a craton is a strong, usually fairly old block of continental crust) collided with and became attached to the East European Craton beginning about 300 million years ago, about the same time as Europe and Africa began to collide with North America to form the Appalachians. Here, the collision produced the Ural Mountains (orogeny means mountain building). The Ural-building collision went on for close to 100 million years.
Much longer ago, at least 520 million years ago and maybe as long ago as 650 million years, a relatively small continental block, labeled “Timan-Pechora Basin” in the image, was amalgamated to the East European Craton. The Timan Suture marks the position of that collision. Today that’s just a range of low hills, but it would have been high mountains at the time of the collision. The Timan-Pechora block was fully part of the East European Craton when Siberia collided with both of them.
For a sense of scale, the distance along the coastline (edge of data) from the Timan Suture to the thin black line is about 400 miles.

This is a very broad-brush look at these magnetic data (I spent the year 1990 making detailed interpretations of the maps for oil exploration).

No comments:

Post a Comment