Pressure-Temperature-time-Deformation (P-T-t-D) History of High-Grade Gneisses of the Port aux Basque Area, Southwest Newfoundland, Canada
A polyphase deformation history (D1-D4) and upper amphibolite facies metamorphism characterize the Port aux Basques Gneisses. Late-D1 to early D2 kyanite porphyroblasts each contain inclusion trails that preserve S1. Reaction out of muscovite, staurolite and kyanite in favor of sillimanite + garnet...
Main Author: | |
---|---|
Other Authors: | , , , |
Format: | Thesis |
Language: | English |
Published: |
1994
|
Subjects: | |
Online Access: | http://hdl.handle.net/1903/29506 https://doi.org/10.13016/avrx-avdm |
id |
ftunivmaryland:oai:drum.lib.umd.edu:1903/29506 |
---|---|
record_format |
openpolar |
spelling |
ftunivmaryland:oai:drum.lib.umd.edu:1903/29506 2023-05-15T17:22:39+02:00 Pressure-Temperature-time-Deformation (P-T-t-D) History of High-Grade Gneisses of the Port aux Basque Area, Southwest Newfoundland, Canada Burgess, Jerry Lee Brown, Michael Digital Repository at the University of Maryland University of Maryland (College Park, Md) Geology 1994 application/pdf http://hdl.handle.net/1903/29506 https://doi.org/10.13016/avrx-avdm en_US eng https://doi.org/10.13016/avrx-avdm ILLiad # 1549052 http://hdl.handle.net/1903/29506 Thesis 1994 ftunivmaryland https://doi.org/10.13016/avrx-avdm 2023-01-15T17:49:38Z A polyphase deformation history (D1-D4) and upper amphibolite facies metamorphism characterize the Port aux Basques Gneisses. Late-D1 to early D2 kyanite porphyroblasts each contain inclusion trails that preserve S1. Reaction out of muscovite, staurolite and kyanite in favor of sillimanite + garnet + alkali feldspar-bearing assemblages in the matapelitic gneisses record syn- to late- D2 peak metamorphic conditions. Isograd surfaces related to syn-D2 metamorphism were probably subhorizontal to inclined but not their metamorphism were probably subhorizontal to incline but now their map pattern reflects subsequent deformation by D3. Fluid-present melting initiated in the kyanite zone and continued into the sillimanite zone. Metamorphic conditions increase to the southeast with 'peak' temperatures of c. 700-750° at 8-9 kbar associated with the D2/M2 thermal regime. A Pb207/Pb206 date of c. 417 Ma was obtained from titanite in high-grade rocks of the Harbour le Cou Group. This date provides a minimum contraint for the M2 event. Hornblende from a nearby amphibolite yields an 40Ar/39Ar isotope correlation date of c. 419 Ma. Muscovite at the same locality records a 40Ar/39Ar plateau date of 391 Ma. Hornblende and muscovite separates from rocks of the Port aux Basques Complex yield similar 40Ar/39Ar dates. Calculations indicate that post- D3 cooling rates of approximately 8-1°C/Ma are required for the area. They kyanite to sillimanite transition and D2 structures suggest a clockwise trajectory in P-T space as a result of Silurian orogenesis. Thesis Newfoundland University of Maryland: Digital Repository (DRUM) Canada |
institution |
Open Polar |
collection |
University of Maryland: Digital Repository (DRUM) |
op_collection_id |
ftunivmaryland |
language |
English |
description |
A polyphase deformation history (D1-D4) and upper amphibolite facies metamorphism characterize the Port aux Basques Gneisses. Late-D1 to early D2 kyanite porphyroblasts each contain inclusion trails that preserve S1. Reaction out of muscovite, staurolite and kyanite in favor of sillimanite + garnet + alkali feldspar-bearing assemblages in the matapelitic gneisses record syn- to late- D2 peak metamorphic conditions. Isograd surfaces related to syn-D2 metamorphism were probably subhorizontal to inclined but not their metamorphism were probably subhorizontal to incline but now their map pattern reflects subsequent deformation by D3. Fluid-present melting initiated in the kyanite zone and continued into the sillimanite zone. Metamorphic conditions increase to the southeast with 'peak' temperatures of c. 700-750° at 8-9 kbar associated with the D2/M2 thermal regime. A Pb207/Pb206 date of c. 417 Ma was obtained from titanite in high-grade rocks of the Harbour le Cou Group. This date provides a minimum contraint for the M2 event. Hornblende from a nearby amphibolite yields an 40Ar/39Ar isotope correlation date of c. 419 Ma. Muscovite at the same locality records a 40Ar/39Ar plateau date of 391 Ma. Hornblende and muscovite separates from rocks of the Port aux Basques Complex yield similar 40Ar/39Ar dates. Calculations indicate that post- D3 cooling rates of approximately 8-1°C/Ma are required for the area. They kyanite to sillimanite transition and D2 structures suggest a clockwise trajectory in P-T space as a result of Silurian orogenesis. |
author2 |
Brown, Michael Digital Repository at the University of Maryland University of Maryland (College Park, Md) Geology |
format |
Thesis |
author |
Burgess, Jerry Lee |
spellingShingle |
Burgess, Jerry Lee Pressure-Temperature-time-Deformation (P-T-t-D) History of High-Grade Gneisses of the Port aux Basque Area, Southwest Newfoundland, Canada |
author_facet |
Burgess, Jerry Lee |
author_sort |
Burgess, Jerry Lee |
title |
Pressure-Temperature-time-Deformation (P-T-t-D) History of High-Grade Gneisses of the Port aux Basque Area, Southwest Newfoundland, Canada |
title_short |
Pressure-Temperature-time-Deformation (P-T-t-D) History of High-Grade Gneisses of the Port aux Basque Area, Southwest Newfoundland, Canada |
title_full |
Pressure-Temperature-time-Deformation (P-T-t-D) History of High-Grade Gneisses of the Port aux Basque Area, Southwest Newfoundland, Canada |
title_fullStr |
Pressure-Temperature-time-Deformation (P-T-t-D) History of High-Grade Gneisses of the Port aux Basque Area, Southwest Newfoundland, Canada |
title_full_unstemmed |
Pressure-Temperature-time-Deformation (P-T-t-D) History of High-Grade Gneisses of the Port aux Basque Area, Southwest Newfoundland, Canada |
title_sort |
pressure-temperature-time-deformation (p-t-t-d) history of high-grade gneisses of the port aux basque area, southwest newfoundland, canada |
publishDate |
1994 |
url |
http://hdl.handle.net/1903/29506 https://doi.org/10.13016/avrx-avdm |
geographic |
Canada |
geographic_facet |
Canada |
genre |
Newfoundland |
genre_facet |
Newfoundland |
op_relation |
https://doi.org/10.13016/avrx-avdm ILLiad # 1549052 http://hdl.handle.net/1903/29506 |
op_doi |
https://doi.org/10.13016/avrx-avdm |
_version_ |
1766109437843472384 |