Continental Extensional Tectonics - The Paparoa Metamorphic Core Complex of Westland, New Zealand
Cretaceous continental extension was accommodated by the development of the Paparoa Metamorphic Core Complex, resulting in the separation of New Zealand from Gondwana. High grade (Lower Plate) and low grade (Upper Plate) rocks are separated by the Ohika and Pike Detachment Faults. The two detachment...
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ftunivcanter:oai:ir.canterbury.ac.nz:10092/1425 2023-05-15T16:30:16+02:00 Continental Extensional Tectonics - The Paparoa Metamorphic Core Complex of Westland, New Zealand Herd, Michelle Erica June 2007 application/pdf http://hdl.handle.net/10092/1425 https://doi.org/10.26021/7128 en eng University of Canterbury. Geological Sciences NZCU http://hdl.handle.net/10092/1425 http://dx.doi.org/10.26021/7128 Copyright Michelle Erica June Herd https://canterbury.libguides.com/rights/theses Paparoa metamorphic core complex continental extension tectonics Theses / Dissertations 2007 ftunivcanter https://doi.org/10.26021/7128 2022-09-08T13:34:15Z Cretaceous continental extension was accommodated by the development of the Paparoa Metamorphic Core Complex, resulting in the separation of New Zealand from Gondwana. High grade (Lower Plate) and low grade (Upper Plate) rocks are separated by the Ohika and Pike Detachment Faults. The two detachment faults have distinctly different histories, with greater exhumation along the Pike Detachment Fault. The onset of crustal extension is proposed to have commenced along the Pike Detachment Fault at 116.2 ± 5.9 Ma (Rb/Sr dating). Both geochemical and geochronological approaches are adopted for this thesis, through the in situ analysis of oxygen and hafnium isotope ratios, trace metals and U-Pb content. Chemical changes are tracked during the petrogenesis of the Buckland Granite, with mafic replenishment observed in the later stages of crystallisation. Crystallisation temperatures of the Buckland Granite are calculated using zircon saturation thermometry, with an average Ti-in-zircon temperature of 697℃ (upper-amphibolite facies). Inherited zircons in Lower Plate rocks show distinct age peaks at c. 1000, 600 and 300 Ma, illustrating the incorporation of heterogeneous local crust (Greenland Group and Karamea Batholith). Model ages (TDM) are calculated for inherited zircons of the Lower Plate rocks, which record the time at which magma bodies (zircon host rocks) were extracted from the mantle. Maximum and minimum model ages for the Buckland Granite average at 3410 Ma and 2969 Ma, with the maximum TDM value of 3410 Ma coinciding with the proposed major crustal formation event of the Gondwana supercontinent at c. 3.4-3.5 Ga. Two distinct U-Pb zircon age peaks are observed in the Buckland Granite at 102.4 ± 0.7 and 110.3 ± 0.9 Ma. The 110.3 ± 0.9 Ma age is interpreted as the crystallisation age of the pluton, while the 102.4 ± 0.7 is proposed to represent a younger thermal (magmatic?) event associated with the 101-102 Ma Stitts Tuff. Other/Unknown Material Greenland University of Canterbury, Christchurch: UC Research Repository Greenland New Zealand |
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Open Polar |
collection |
University of Canterbury, Christchurch: UC Research Repository |
op_collection_id |
ftunivcanter |
language |
English |
topic |
Paparoa metamorphic core complex continental extension tectonics |
spellingShingle |
Paparoa metamorphic core complex continental extension tectonics Herd, Michelle Erica June Continental Extensional Tectonics - The Paparoa Metamorphic Core Complex of Westland, New Zealand |
topic_facet |
Paparoa metamorphic core complex continental extension tectonics |
description |
Cretaceous continental extension was accommodated by the development of the Paparoa Metamorphic Core Complex, resulting in the separation of New Zealand from Gondwana. High grade (Lower Plate) and low grade (Upper Plate) rocks are separated by the Ohika and Pike Detachment Faults. The two detachment faults have distinctly different histories, with greater exhumation along the Pike Detachment Fault. The onset of crustal extension is proposed to have commenced along the Pike Detachment Fault at 116.2 ± 5.9 Ma (Rb/Sr dating). Both geochemical and geochronological approaches are adopted for this thesis, through the in situ analysis of oxygen and hafnium isotope ratios, trace metals and U-Pb content. Chemical changes are tracked during the petrogenesis of the Buckland Granite, with mafic replenishment observed in the later stages of crystallisation. Crystallisation temperatures of the Buckland Granite are calculated using zircon saturation thermometry, with an average Ti-in-zircon temperature of 697℃ (upper-amphibolite facies). Inherited zircons in Lower Plate rocks show distinct age peaks at c. 1000, 600 and 300 Ma, illustrating the incorporation of heterogeneous local crust (Greenland Group and Karamea Batholith). Model ages (TDM) are calculated for inherited zircons of the Lower Plate rocks, which record the time at which magma bodies (zircon host rocks) were extracted from the mantle. Maximum and minimum model ages for the Buckland Granite average at 3410 Ma and 2969 Ma, with the maximum TDM value of 3410 Ma coinciding with the proposed major crustal formation event of the Gondwana supercontinent at c. 3.4-3.5 Ga. Two distinct U-Pb zircon age peaks are observed in the Buckland Granite at 102.4 ± 0.7 and 110.3 ± 0.9 Ma. The 110.3 ± 0.9 Ma age is interpreted as the crystallisation age of the pluton, while the 102.4 ± 0.7 is proposed to represent a younger thermal (magmatic?) event associated with the 101-102 Ma Stitts Tuff. |
format |
Other/Unknown Material |
author |
Herd, Michelle Erica June |
author_facet |
Herd, Michelle Erica June |
author_sort |
Herd, Michelle Erica June |
title |
Continental Extensional Tectonics - The Paparoa Metamorphic Core Complex of Westland, New Zealand |
title_short |
Continental Extensional Tectonics - The Paparoa Metamorphic Core Complex of Westland, New Zealand |
title_full |
Continental Extensional Tectonics - The Paparoa Metamorphic Core Complex of Westland, New Zealand |
title_fullStr |
Continental Extensional Tectonics - The Paparoa Metamorphic Core Complex of Westland, New Zealand |
title_full_unstemmed |
Continental Extensional Tectonics - The Paparoa Metamorphic Core Complex of Westland, New Zealand |
title_sort |
continental extensional tectonics - the paparoa metamorphic core complex of westland, new zealand |
publisher |
University of Canterbury. Geological Sciences |
publishDate |
2007 |
url |
http://hdl.handle.net/10092/1425 https://doi.org/10.26021/7128 |
geographic |
Greenland New Zealand |
geographic_facet |
Greenland New Zealand |
genre |
Greenland |
genre_facet |
Greenland |
op_relation |
NZCU http://hdl.handle.net/10092/1425 http://dx.doi.org/10.26021/7128 |
op_rights |
Copyright Michelle Erica June Herd https://canterbury.libguides.com/rights/theses |
op_doi |
https://doi.org/10.26021/7128 |
_version_ |
1766019995784970240 |