Latest Iapetus Ocean Stories
In devising his theories about evolution, Darwin theorized that species evolved on Earth slowly over millions of years. However, the fossil record doesn’t agree with the slow-and-steady model as a massive explosion of species took place 530 million years ago during the Cambrian era.
By Schofield, D I Evans, J A; Millar, I L; Wilby, P R; Aspden, J A A new U-Pb date of 615.2 +- 13 (2sigma) Ma for the Twt Hill Granite, North Wales, contrasts with an Rb-Sr isochron age of 491 +- 12 (2sigma) Ma from the same body.
By Steinhoefel, Grit Hegner, Ernst; Oliver, Grahame J H Abstract: Major- and trace-element data and Nd isotope compositions for granitoid samples from the Grampian Highlands in Scotland show a systematic evolution in the composition of their sources in the course of the Caledonian Orogeny.