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Latest Caledonian orogeny Stories

2008-09-19 03:00:23

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. The latter age is thought to result from isotope resetting during regional low-grade metamorphism or fault reactivation. The Rb-Sr age also coincides with the onset of latest Cambrian to Early Tremadoc regression and is taken to reflect tectonic uplift prior to...

2008-08-01 03:00:26

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. Granitoids of 511- 451 Ma, related to the collision of the Midland Valley island arc with the Grampian terrane, show S-type affinity and fractionated REE patterns with minor Eu anomalies and low initial...

2008-06-06 03:00:33

By Oliver, Grahame J H Wilde, Simon A; Wan, Yusheng Abstract: Thirty-seven granitoids from Scotland have been dated using the sensitive high-resolution ion microprobe zircon method. Granitoids were intruded during: (1) crustal stretching at c. 600 Ma after Rodinia broke up (A-types); (2) the Grampian event of crustal thickening when the Midland Valley Arc terrane collided with Laurentia at c. 470 Ma (S-types); (3) erosion and decompression of the over-thickened Laurentian margin at c. 455...

2005-06-29 21:28:21

(Kingston, ON) "“ Geologists at Queen's University have discovered that the time it takes for mountain ranges to form is millions of years shorter than previously thought. This controversial finding could have implications for our understanding of other geological processes that shaped the Earth, says Professor James Lee and postdoctoral fellow Alfredo Camacho of Queen's Geological Sciences and Geological Engineering Department. The study will appear in the June 30 edition of the...


Word of the Day
call-note
  • The call or cry of a bird or other animal to its mate or its young.
'Call-note' is newer than 'bird-call,' which originally referred to 'an instrument for imitating the note of birds' but now also refers to 'the song or cry of a bird.'
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