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The tectonothermal evolution and provenance of the Tyrone Central Inlier, Ireland: Grampian imbrication of an outboard Laurentian microcontinent?

Chew, D M; Flowerdew, M J; Page, Laurence LU ; Crowley, Q G; Daly, J S; Cooper, M and Whitehouse, M J (2008) In Journal of the Geological Society 165(3). p.675-685
Abstract
The Tyrone Central Inlier is a metamorphic terrane of uncertain affinity situated outboard of the main Dalradian outcrop (south of the Fair Head-Clew Bay Line) and could represent sub-arc basement to part of the enigmatic Midland Valley Terrane. Using a combination of isotopic, structural and petrographic evidence, the tectonothermal evolution of the Tyrone Central Inlier was investigated. Sillimanite-bearing 14 metamorphic assemblages (c. 670 degrees C, 6.8 kbar) and leucosomes in paragneisses are cut by granite pegmatites, which post-date two deformation fabrics. The leucosomes yield a weighted average Pb-207/Ph-206 zircon age of 467 +/- 12 Ma whereas the main fabric yields a Ar-40-Ar-39 biotite cooling age of 468 +/- 1.4 Ma. The... (More)
The Tyrone Central Inlier is a metamorphic terrane of uncertain affinity situated outboard of the main Dalradian outcrop (south of the Fair Head-Clew Bay Line) and could represent sub-arc basement to part of the enigmatic Midland Valley Terrane. Using a combination of isotopic, structural and petrographic evidence, the tectonothermal evolution of the Tyrone Central Inlier was investigated. Sillimanite-bearing 14 metamorphic assemblages (c. 670 degrees C, 6.8 kbar) and leucosomes in paragneisses are cut by granite pegmatites, which post-date two deformation fabrics. The leucosomes yield a weighted average Pb-207/Ph-206 zircon age of 467 +/- 12 Ma whereas the main fabric yields a Ar-40-Ar-39 biotite cooling age of 468 +/- 1.4 Ma. The pegmatites yield 457 +/- 7 Ma and 458 +/- 7 Ma Rb-Sr muscovite-feldspar ages and Ar-40-Ar-39 step-heating plateaux of 466 +/- 1 Ma and 468 +/- 1 Ma, respectively. The metasedimentary rocks yield Palaeoproterozoic Sm-Nd model ages and laser ablation inductively coupled plasma mass spectrometry detrital zircon U-Pb analyses from a psammitic gneiss yield age populations at 1.05-1.2, 1.5, 1.8, 2.7 and 3.1 Ga. Combined, these data permit correlation of the Tyrone Central Inlier with either the Argyll or the Southern Highland Group of the Dalradian Supergroup. The inlier was thus part of Laurentia onto which the Tyrone ophiolite was obducted. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of the Geological Society
volume
165
issue
3
pages
675 - 685
publisher
The Geological Society Publishing House
external identifiers
  • wos:000256094300007
  • scopus:44449152037
ISSN
2041-479X
DOI
10.1144/0016-76492007-120
language
English
LU publication?
yes
id
a655cd23-dfca-4a79-9caa-bae1a929364e (old id 1203333)
date added to LUP
2008-09-15 16:41:59
date last changed
2017-03-05 03:29:50
@article{a655cd23-dfca-4a79-9caa-bae1a929364e,
  abstract     = {The Tyrone Central Inlier is a metamorphic terrane of uncertain affinity situated outboard of the main Dalradian outcrop (south of the Fair Head-Clew Bay Line) and could represent sub-arc basement to part of the enigmatic Midland Valley Terrane. Using a combination of isotopic, structural and petrographic evidence, the tectonothermal evolution of the Tyrone Central Inlier was investigated. Sillimanite-bearing 14 metamorphic assemblages (c. 670 degrees C, 6.8 kbar) and leucosomes in paragneisses are cut by granite pegmatites, which post-date two deformation fabrics. The leucosomes yield a weighted average Pb-207/Ph-206 zircon age of 467 +/- 12 Ma whereas the main fabric yields a Ar-40-Ar-39 biotite cooling age of 468 +/- 1.4 Ma. The pegmatites yield 457 +/- 7 Ma and 458 +/- 7 Ma Rb-Sr muscovite-feldspar ages and Ar-40-Ar-39 step-heating plateaux of 466 +/- 1 Ma and 468 +/- 1 Ma, respectively. The metasedimentary rocks yield Palaeoproterozoic Sm-Nd model ages and laser ablation inductively coupled plasma mass spectrometry detrital zircon U-Pb analyses from a psammitic gneiss yield age populations at 1.05-1.2, 1.5, 1.8, 2.7 and 3.1 Ga. Combined, these data permit correlation of the Tyrone Central Inlier with either the Argyll or the Southern Highland Group of the Dalradian Supergroup. The inlier was thus part of Laurentia onto which the Tyrone ophiolite was obducted.},
  author       = {Chew, D M and Flowerdew, M J and Page, Laurence and Crowley, Q G and Daly, J S and Cooper, M and Whitehouse, M J},
  issn         = {2041-479X},
  language     = {eng},
  number       = {3},
  pages        = {675--685},
  publisher    = {The Geological Society Publishing House},
  series       = {Journal of the Geological Society},
  title        = {The tectonothermal evolution and provenance of the Tyrone Central Inlier, Ireland: Grampian imbrication of an outboard Laurentian microcontinent?},
  url          = {http://dx.doi.org/10.1144/0016-76492007-120},
  volume       = {165},
  year         = {2008},
}