Geology and geochronology of the Sub-Antarctic Snares Islands/Tini Heke, New Zealand
The first comprehensive geological map, a summary of lithologies and new radiogenic isotope data (U–Pb, Rb–Sr) are presented for crystalline rocks of the Sub-Antarctic Snares Islands/Tini Heke, 150 km south of Stewart Island. The main lithology is Snares Granite (c. 109 Ma from U–Pb dating of zircon...
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2015
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ftdatacite:10.6084/m9.figshare.1393338.v1 2023-05-15T13:44:34+02:00 Geology and geochronology of the Sub-Antarctic Snares Islands/Tini Heke, New Zealand JM Scott IM Turnbull MW Sagar AJ Tulloch TE Waight JM Palin 2015 https://dx.doi.org/10.6084/m9.figshare.1393338.v1 https://tandf.figshare.com/articles/dataset/Geology_and_geochronology_of_the_Sub_Antarctic_Snares_Islands_Tini_Heke_New_Zealand/1393338/1 unknown Taylor & Francis https://dx.doi.org/10.1080/00288306.2015.1023810 https://dx.doi.org/10.6084/m9.figshare.1393338 Creative Commons Attribution Non Commercial No Derivatives 4.0 International https://creativecommons.org/licenses/by-nc-nd/4.0/legalcode cc-by-nc-nd-4.0 CC-BY-NC-ND Hematology Inorganic Chemistry FOS Chemical sciences Ecology FOS Biological sciences Chemistry Earth and Environmental Sciences Evolutionary Biology Genetics Cell Biology dataset Dataset 2015 ftdatacite https://doi.org/10.6084/m9.figshare.1393338.v1 https://doi.org/10.1080/00288306.2015.1023810 https://doi.org/10.6084/m9.figshare.1393338 2021-11-05T12:55:41Z The first comprehensive geological map, a summary of lithologies and new radiogenic isotope data (U–Pb, Rb–Sr) are presented for crystalline rocks of the Sub-Antarctic Snares Islands/Tini Heke, 150 km south of Stewart Island. The main lithology is Snares Granite (c. 109 Ma from U–Pb dating of zircon), which intrudes Broughton Granodiorite (c. 114 Ma from U–Pb zircon) on Broughton Island. Rafts of schist within Snares Granite are common on the outlying Western Chain islets, and rare on North East and Broughton islands. Zircon grains extracted from one schistose raft on Broughton Island are prismatic and yield an essentially unimodal age population of c. 116 Ma that is within error of the granodiorite. These properties suggest that the dated raft represents a meta-igneous rock despite its mica-rich nature. Some schistose rocks on the Western Chain contain coarse relict plagioclase phenocrysts and appear to have an igneous protolith. No conclusive metasedimentary rocks have been identified, although sillimanite-bearing mica-rich schist occurs on Rua. Deformation of the crystalline rocks occurred after Snares Granite intrusion and before cooling below muscovite K–Ar closure at 400 ± 50 °C at 95 Ma. This period overlaps the age of extensional ductile shear zones on Stewart Island. The discovery of several basaltic dykes, which cut across fabrics and are unmetamorphosed, indicates that volcanic rocks are associated with all Sub-Antarctic island groups. The larger of the islands are overlain by peat, which on North East Island also contains gravel deposits. Dataset Antarc* Antarctic Snares Islands DataCite Metadata Store (German National Library of Science and Technology) Antarctic East Island ENVELOPE(-55.815,-55.815,52.733,52.733) New Zealand Rua ENVELOPE(14.750,14.750,64.583,64.583) |
institution |
Open Polar |
collection |
DataCite Metadata Store (German National Library of Science and Technology) |
op_collection_id |
ftdatacite |
language |
unknown |
topic |
Hematology Inorganic Chemistry FOS Chemical sciences Ecology FOS Biological sciences Chemistry Earth and Environmental Sciences Evolutionary Biology Genetics Cell Biology |
spellingShingle |
Hematology Inorganic Chemistry FOS Chemical sciences Ecology FOS Biological sciences Chemistry Earth and Environmental Sciences Evolutionary Biology Genetics Cell Biology JM Scott IM Turnbull MW Sagar AJ Tulloch TE Waight JM Palin Geology and geochronology of the Sub-Antarctic Snares Islands/Tini Heke, New Zealand |
topic_facet |
Hematology Inorganic Chemistry FOS Chemical sciences Ecology FOS Biological sciences Chemistry Earth and Environmental Sciences Evolutionary Biology Genetics Cell Biology |
description |
The first comprehensive geological map, a summary of lithologies and new radiogenic isotope data (U–Pb, Rb–Sr) are presented for crystalline rocks of the Sub-Antarctic Snares Islands/Tini Heke, 150 km south of Stewart Island. The main lithology is Snares Granite (c. 109 Ma from U–Pb dating of zircon), which intrudes Broughton Granodiorite (c. 114 Ma from U–Pb zircon) on Broughton Island. Rafts of schist within Snares Granite are common on the outlying Western Chain islets, and rare on North East and Broughton islands. Zircon grains extracted from one schistose raft on Broughton Island are prismatic and yield an essentially unimodal age population of c. 116 Ma that is within error of the granodiorite. These properties suggest that the dated raft represents a meta-igneous rock despite its mica-rich nature. Some schistose rocks on the Western Chain contain coarse relict plagioclase phenocrysts and appear to have an igneous protolith. No conclusive metasedimentary rocks have been identified, although sillimanite-bearing mica-rich schist occurs on Rua. Deformation of the crystalline rocks occurred after Snares Granite intrusion and before cooling below muscovite K–Ar closure at 400 ± 50 °C at 95 Ma. This period overlaps the age of extensional ductile shear zones on Stewart Island. The discovery of several basaltic dykes, which cut across fabrics and are unmetamorphosed, indicates that volcanic rocks are associated with all Sub-Antarctic island groups. The larger of the islands are overlain by peat, which on North East Island also contains gravel deposits. |
format |
Dataset |
author |
JM Scott IM Turnbull MW Sagar AJ Tulloch TE Waight JM Palin |
author_facet |
JM Scott IM Turnbull MW Sagar AJ Tulloch TE Waight JM Palin |
author_sort |
JM Scott |
title |
Geology and geochronology of the Sub-Antarctic Snares Islands/Tini Heke, New Zealand |
title_short |
Geology and geochronology of the Sub-Antarctic Snares Islands/Tini Heke, New Zealand |
title_full |
Geology and geochronology of the Sub-Antarctic Snares Islands/Tini Heke, New Zealand |
title_fullStr |
Geology and geochronology of the Sub-Antarctic Snares Islands/Tini Heke, New Zealand |
title_full_unstemmed |
Geology and geochronology of the Sub-Antarctic Snares Islands/Tini Heke, New Zealand |
title_sort |
geology and geochronology of the sub-antarctic snares islands/tini heke, new zealand |
publisher |
Taylor & Francis |
publishDate |
2015 |
url |
https://dx.doi.org/10.6084/m9.figshare.1393338.v1 https://tandf.figshare.com/articles/dataset/Geology_and_geochronology_of_the_Sub_Antarctic_Snares_Islands_Tini_Heke_New_Zealand/1393338/1 |
long_lat |
ENVELOPE(-55.815,-55.815,52.733,52.733) ENVELOPE(14.750,14.750,64.583,64.583) |
geographic |
Antarctic East Island New Zealand Rua |
geographic_facet |
Antarctic East Island New Zealand Rua |
genre |
Antarc* Antarctic Snares Islands |
genre_facet |
Antarc* Antarctic Snares Islands |
op_relation |
https://dx.doi.org/10.1080/00288306.2015.1023810 https://dx.doi.org/10.6084/m9.figshare.1393338 |
op_rights |
Creative Commons Attribution Non Commercial No Derivatives 4.0 International https://creativecommons.org/licenses/by-nc-nd/4.0/legalcode cc-by-nc-nd-4.0 |
op_rightsnorm |
CC-BY-NC-ND |
op_doi |
https://doi.org/10.6084/m9.figshare.1393338.v1 https://doi.org/10.1080/00288306.2015.1023810 https://doi.org/10.6084/m9.figshare.1393338 |
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1766203606076227584 |