Caledonian and Pre-Caledonian orogenic events in Shetland, Scotland : evidence from garnet Lu-Hf and Sm-Nd geochronology. / Walker, Steph; Bird, Anna; Thirlwall, Matthew; Strachan, Rob.

In: Geological Society of London Special Publication, 14.09.2020.

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Caledonian and Pre-Caledonian orogenic events in Shetland, Scotland : evidence from garnet Lu-Hf and Sm-Nd geochronology. / Walker, Steph; Bird, Anna; Thirlwall, Matthew; Strachan, Rob.

In: Geological Society of London Special Publication, 14.09.2020.

Research output: Contribution to journalArticlepeer-review

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@article{82b08993d3ae4312ba090294018df247,
title = "Caledonian and Pre-Caledonian orogenic events in Shetland, Scotland: evidence from garnet Lu-Hf and Sm-Nd geochronology",
abstract = "Garnet Lu-Hf and Sm-Nd ages from the Shetland Caledonides provide evidence of a polyorogenic history as follows: 1) c. 1050 Ma Grenvillian reworking of Neoarchaean basement; 2) c. 910 Ma Renlandian metamorphism of the Westing Group; 3) c. 622-606 Ma metamorphism of the Walls Metamorphic Series but of uncertain significance because the eastern margin of Laurentia is thought to have been in extension at that time; 4) Grampian I ophiolite obduction at c. 491 Ma followed by crustal thickening and metamorphism between c. 485 and c. 466 Ma; 5) Grampian II metamorphism between c. 458 and c. 442 Ma that appears to have been focused in areas where pre-existing foliations were gently-inclined and thus may have been relatively easily reworked; 6) Scandian metamorphism at c. 430 Ma, although the paucity of these ages suggests that much of Shetland did not attain temperatures for garnet growth. There is no significant difference in the timing of Caledonian orogenic events either side of the Walls Boundary Fault, although this need not preclude linkage with the Great Glen Fault. However, the incompatibility of Ediacaran events either side of the WallsBoundary Fault may indicate significant lateral displacement and requires furtherinvestigation.",
author = "Steph Walker and Anna Bird and Matthew Thirlwall and Rob Strachan",
year = "2020",
month = sep,
day = "14",
doi = "10.1144/SP503-2020-32",
language = "English",
journal = "Geological Society of London Special Publication",
issn = "0305-8719",
publisher = "Geological Society of London",

}

RIS

TY - JOUR

T1 - Caledonian and Pre-Caledonian orogenic events in Shetland, Scotland

T2 - evidence from garnet Lu-Hf and Sm-Nd geochronology

AU - Walker, Steph

AU - Bird, Anna

AU - Thirlwall, Matthew

AU - Strachan, Rob

PY - 2020/9/14

Y1 - 2020/9/14

N2 - Garnet Lu-Hf and Sm-Nd ages from the Shetland Caledonides provide evidence of a polyorogenic history as follows: 1) c. 1050 Ma Grenvillian reworking of Neoarchaean basement; 2) c. 910 Ma Renlandian metamorphism of the Westing Group; 3) c. 622-606 Ma metamorphism of the Walls Metamorphic Series but of uncertain significance because the eastern margin of Laurentia is thought to have been in extension at that time; 4) Grampian I ophiolite obduction at c. 491 Ma followed by crustal thickening and metamorphism between c. 485 and c. 466 Ma; 5) Grampian II metamorphism between c. 458 and c. 442 Ma that appears to have been focused in areas where pre-existing foliations were gently-inclined and thus may have been relatively easily reworked; 6) Scandian metamorphism at c. 430 Ma, although the paucity of these ages suggests that much of Shetland did not attain temperatures for garnet growth. There is no significant difference in the timing of Caledonian orogenic events either side of the Walls Boundary Fault, although this need not preclude linkage with the Great Glen Fault. However, the incompatibility of Ediacaran events either side of the WallsBoundary Fault may indicate significant lateral displacement and requires furtherinvestigation.

AB - Garnet Lu-Hf and Sm-Nd ages from the Shetland Caledonides provide evidence of a polyorogenic history as follows: 1) c. 1050 Ma Grenvillian reworking of Neoarchaean basement; 2) c. 910 Ma Renlandian metamorphism of the Westing Group; 3) c. 622-606 Ma metamorphism of the Walls Metamorphic Series but of uncertain significance because the eastern margin of Laurentia is thought to have been in extension at that time; 4) Grampian I ophiolite obduction at c. 491 Ma followed by crustal thickening and metamorphism between c. 485 and c. 466 Ma; 5) Grampian II metamorphism between c. 458 and c. 442 Ma that appears to have been focused in areas where pre-existing foliations were gently-inclined and thus may have been relatively easily reworked; 6) Scandian metamorphism at c. 430 Ma, although the paucity of these ages suggests that much of Shetland did not attain temperatures for garnet growth. There is no significant difference in the timing of Caledonian orogenic events either side of the Walls Boundary Fault, although this need not preclude linkage with the Great Glen Fault. However, the incompatibility of Ediacaran events either side of the WallsBoundary Fault may indicate significant lateral displacement and requires furtherinvestigation.

U2 - 10.1144/SP503-2020-32

DO - 10.1144/SP503-2020-32

M3 - Article

JO - Geological Society of London Special Publication

JF - Geological Society of London Special Publication

SN - 0305-8719

ER -