Biodiversity and palaeoecological significance of tertiary fossil floras from King George Island, West Antarctica

Palaeogene volcanics with plant-bearing sediment intercalations crop out extensively on King George Island in the South Shetland Islands, West Antarctica. The plant fossil assemblages are the most complete Palaeogene terrestrial foliar record in Antarctica. Compositional variations in the flora have...

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Main Author: Hunt, Richard John
Format: Thesis
Language:English
Published: University of Leeds 2001
Subjects:
Online Access:https://etheses.whiterose.ac.uk/15217/
https://etheses.whiterose.ac.uk/15217/1/511653.pdf
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spelling ftwhiterose:oai:etheses.whiterose.ac.uk:15217 2023-05-15T13:38:16+02:00 Biodiversity and palaeoecological significance of tertiary fossil floras from King George Island, West Antarctica Hunt, Richard John 2001-11 text https://etheses.whiterose.ac.uk/15217/ https://etheses.whiterose.ac.uk/15217/1/511653.pdf en eng University of Leeds https://etheses.whiterose.ac.uk/15217/1/511653.pdf Hunt, Richard John (2001) Biodiversity and palaeoecological significance of tertiary fossil floras from King George Island, West Antarctica. PhD thesis, University of Leeds. Thesis NonPeerReviewed 2001 ftwhiterose 2023-01-30T21:23:28Z Palaeogene volcanics with plant-bearing sediment intercalations crop out extensively on King George Island in the South Shetland Islands, West Antarctica. The plant fossil assemblages are the most complete Palaeogene terrestrial foliar record in Antarctica. Compositional variations in the flora have previously been used to construct climate change models for the Tertiary. King George Island is part of the late Triassic to Recent, Andean - West Antarctic subducting margin. Eastwards subduction oceanic crust beneath the Antarctic Peninsula resulted in mountain building and crustal melting at depth that in turn led to large stratovolcanoes and active pyroclastic volcanism (Leat et al., 1995). Consequently the flora is preserved in a range of primary and reworked volcaniclastic sediments, that were deposited in lacustrine and ephemeral lacustrine basins developed on the volcanic surface. The King George Island flora consists of impressions and carbonised compressions of leaves of angiosperms, gymnosperms, and ferns, in addition to new records of an angiosperm infloresence, fruits and coniferous cones. The flora comprises vegetation elements with a disjunct modern Southern Hemisphere distribution, such as Cunoniaceae, Nothofagaceae, Proteaceae, Sterculiaceae, Lauraceae and Myrtaceae. Close affinities are suggested with the cool to warm temperate forests of southern South America. Morphotype analyses based on leaf venation architecture have been used to group the flora into 85 morphotypes based on 428 specimens. The morphotypes have been used in foliar physiognomic and nearest living relative palaeoclimate analyses, which suggest warm microthermal climates for the Middle Eocene in West Antarctica. The Dragon Glacier and Mt. Wawel floras from Point Hennequin are currently regarded as impoverished Upper Oligocene, post-glacial floras. However, 40Ar/39Ar dating of the encapsulating lavas indicates that they are Middle Eocene in age (44 - 49 Ma) and field collections have yielded a diverse range of plant fossils from the ... Thesis Antarc* Antarctic Antarctic Peninsula Antarctica King George Island South Shetland Islands West Antarctica White Rose eTheses Online (Universities Leeds, Sheffield, York) Antarctic Antarctic Peninsula Cones The ENVELOPE(78.344,78.344,-68.635,-68.635) Cones, The ENVELOPE(78.344,78.344,-68.635,-68.635) Dragon Glacier ENVELOPE(-58.372,-58.372,-62.115,-62.115) Hennequin ENVELOPE(-58.350,-58.350,-62.117,-62.117) King George Island Point Hennequin ENVELOPE(-58.400,-58.400,-62.133,-62.133) South Shetland Islands The Antarctic West Antarctica
institution Open Polar
collection White Rose eTheses Online (Universities Leeds, Sheffield, York)
op_collection_id ftwhiterose
language English
description Palaeogene volcanics with plant-bearing sediment intercalations crop out extensively on King George Island in the South Shetland Islands, West Antarctica. The plant fossil assemblages are the most complete Palaeogene terrestrial foliar record in Antarctica. Compositional variations in the flora have previously been used to construct climate change models for the Tertiary. King George Island is part of the late Triassic to Recent, Andean - West Antarctic subducting margin. Eastwards subduction oceanic crust beneath the Antarctic Peninsula resulted in mountain building and crustal melting at depth that in turn led to large stratovolcanoes and active pyroclastic volcanism (Leat et al., 1995). Consequently the flora is preserved in a range of primary and reworked volcaniclastic sediments, that were deposited in lacustrine and ephemeral lacustrine basins developed on the volcanic surface. The King George Island flora consists of impressions and carbonised compressions of leaves of angiosperms, gymnosperms, and ferns, in addition to new records of an angiosperm infloresence, fruits and coniferous cones. The flora comprises vegetation elements with a disjunct modern Southern Hemisphere distribution, such as Cunoniaceae, Nothofagaceae, Proteaceae, Sterculiaceae, Lauraceae and Myrtaceae. Close affinities are suggested with the cool to warm temperate forests of southern South America. Morphotype analyses based on leaf venation architecture have been used to group the flora into 85 morphotypes based on 428 specimens. The morphotypes have been used in foliar physiognomic and nearest living relative palaeoclimate analyses, which suggest warm microthermal climates for the Middle Eocene in West Antarctica. The Dragon Glacier and Mt. Wawel floras from Point Hennequin are currently regarded as impoverished Upper Oligocene, post-glacial floras. However, 40Ar/39Ar dating of the encapsulating lavas indicates that they are Middle Eocene in age (44 - 49 Ma) and field collections have yielded a diverse range of plant fossils from the ...
format Thesis
author Hunt, Richard John
spellingShingle Hunt, Richard John
Biodiversity and palaeoecological significance of tertiary fossil floras from King George Island, West Antarctica
author_facet Hunt, Richard John
author_sort Hunt, Richard John
title Biodiversity and palaeoecological significance of tertiary fossil floras from King George Island, West Antarctica
title_short Biodiversity and palaeoecological significance of tertiary fossil floras from King George Island, West Antarctica
title_full Biodiversity and palaeoecological significance of tertiary fossil floras from King George Island, West Antarctica
title_fullStr Biodiversity and palaeoecological significance of tertiary fossil floras from King George Island, West Antarctica
title_full_unstemmed Biodiversity and palaeoecological significance of tertiary fossil floras from King George Island, West Antarctica
title_sort biodiversity and palaeoecological significance of tertiary fossil floras from king george island, west antarctica
publisher University of Leeds
publishDate 2001
url https://etheses.whiterose.ac.uk/15217/
https://etheses.whiterose.ac.uk/15217/1/511653.pdf
long_lat ENVELOPE(78.344,78.344,-68.635,-68.635)
ENVELOPE(78.344,78.344,-68.635,-68.635)
ENVELOPE(-58.372,-58.372,-62.115,-62.115)
ENVELOPE(-58.350,-58.350,-62.117,-62.117)
ENVELOPE(-58.400,-58.400,-62.133,-62.133)
geographic Antarctic
Antarctic Peninsula
Cones The
Cones, The
Dragon Glacier
Hennequin
King George Island
Point Hennequin
South Shetland Islands
The Antarctic
West Antarctica
geographic_facet Antarctic
Antarctic Peninsula
Cones The
Cones, The
Dragon Glacier
Hennequin
King George Island
Point Hennequin
South Shetland Islands
The Antarctic
West Antarctica
genre Antarc*
Antarctic
Antarctic Peninsula
Antarctica
King George Island
South Shetland Islands
West Antarctica
genre_facet Antarc*
Antarctic
Antarctic Peninsula
Antarctica
King George Island
South Shetland Islands
West Antarctica
op_relation https://etheses.whiterose.ac.uk/15217/1/511653.pdf
Hunt, Richard John (2001) Biodiversity and palaeoecological significance of tertiary fossil floras from King George Island, West Antarctica. PhD thesis, University of Leeds.
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