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Latest 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...

2008-02-29 03:00:28

By Houston, John Hart, Dan; Houston, Andrew Abstract: Neogene sediments in the northern Chilean forearc display a wide range of near syndepositional structures. Analysis of the origin and distribution of these structures in space and time offers new insights into the development of the forearc basins. The structures are described in detail and show many features associated with soft-sediment deformation, pseudo-diapirism and slope failure. Synsedimentary deformation reached a peak in the...

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2006-01-31 07:59:52

Two new studies by a University of Rochester researcher show that mountain ranges rise to their height in as little as two million years--several times faster than geologists have always thought. Each of the findings came from two pioneering methods of measuring ancient mountain elevations, and the results are in tight agreement. The research papers, appearing in today's issue of Science and next week's issue of Earth and Planetary Science Letters, mean scientists will have to re-evaluate...

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
snash
  • To talk saucily.
  • Insolent, opprobrious language; impertinent abuse.
This word is Scots in origin and probably imitative.