Formation of Fe-rich subsurface precipitate layers on White Island, New Zealand
White Island is a highly active volcano with an acidic, S-rich hydrothermal system in the Bay of Plenty, North Island, New Zealand. In this acidic environment a series of subsurface Fe-rich layers are ubiquitous in the crater sediments at shallow depth and are capable of modifying the flow and gas f...
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University of Canterbury. Geological Sciences
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ftunivcanter:oai:ir.canterbury.ac.nz:10092/9660 2023-05-15T18:43:32+02:00 Formation of Fe-rich subsurface precipitate layers on White Island, New Zealand Win, Noel Antony 2014 application/pdf http://hdl.handle.net/10092/9660 https://doi.org/10.26021/7944 en eng University of Canterbury. Geological Sciences NZCU http://hdl.handle.net/10092/9660 http://dx.doi.org/10.26021/7944 Copyright Noel Antony Win https://canterbury.libguides.com/rights/theses White Island Volcanic Hydrothermal Geochemistry Microbes Fe-rich precipitates Epithermal Theses / Dissertations 2014 ftunivcanter https://doi.org/10.26021/7944 2022-09-08T13:37:46Z White Island is a highly active volcano with an acidic, S-rich hydrothermal system in the Bay of Plenty, North Island, New Zealand. In this acidic environment a series of subsurface Fe-rich layers are ubiquitous in the crater sediments at shallow depth and are capable of modifying the flow and gas flux dynamics in the system. The mineralogy of the subsurface Fe-rich layer(s) and the processes leading to their formation are unknown. Here the mineralogy and formation of the subsurface Fe-rich layers in relation to the surface and subsurface environment(s) within the Main Crater at White Island are assessed. Based on geochemical analyses, subsurface Fe-rich crusts are composed of a mix of jarosite and goethite, cementing crater fill sediments into cohesive layers. Saturation index (SI) and Eh/pH assessments identify that fluids evolved at White Island are undersaturated with respect to the mineral phases present in the Fe-rich subsurface layers. Formation of the Fe-rich subsurface layers is most likely related to the transition between atmospheric gases and/or meteoric water mixing with hydrothermal fluids. This transition zone creates an environment conducive to forming jarosite and goethite forming in the same layer. Additionally, subsurface sediments including the Fe-rich layers show a consistent organic carbon isotopic signature of -23 ‰. Microscopic investigations confirm diatoms and microbes are present in the subsurface Fe-rich layers. The full extent of microbial activity in relation to the Fe-rich layers at White Island still requires further investigation. Based on chemical extractions for isotopic analyses, Fe-rich layers are shown to preserve δ¹³C signatures indicative of microbial life. Interface zones such as those identified in the hydrothermal environment at White Island can create metal-rich deposits and habitable/preservative microbial environments as well as affecting the macroscopic dynamics of volcanic and epithermal systems. Other/Unknown Material White Island University of Canterbury, Christchurch: UC Research Repository Bay of Plenty ENVELOPE(-128.761,-128.761,52.837,52.837) Main Crater ENVELOPE(167.167,167.167,-77.533,-77.533) New Zealand White Island ENVELOPE(48.583,48.583,-66.733,-66.733) |
institution |
Open Polar |
collection |
University of Canterbury, Christchurch: UC Research Repository |
op_collection_id |
ftunivcanter |
language |
English |
topic |
White Island Volcanic Hydrothermal Geochemistry Microbes Fe-rich precipitates Epithermal |
spellingShingle |
White Island Volcanic Hydrothermal Geochemistry Microbes Fe-rich precipitates Epithermal Win, Noel Antony Formation of Fe-rich subsurface precipitate layers on White Island, New Zealand |
topic_facet |
White Island Volcanic Hydrothermal Geochemistry Microbes Fe-rich precipitates Epithermal |
description |
White Island is a highly active volcano with an acidic, S-rich hydrothermal system in the Bay of Plenty, North Island, New Zealand. In this acidic environment a series of subsurface Fe-rich layers are ubiquitous in the crater sediments at shallow depth and are capable of modifying the flow and gas flux dynamics in the system. The mineralogy of the subsurface Fe-rich layer(s) and the processes leading to their formation are unknown. Here the mineralogy and formation of the subsurface Fe-rich layers in relation to the surface and subsurface environment(s) within the Main Crater at White Island are assessed. Based on geochemical analyses, subsurface Fe-rich crusts are composed of a mix of jarosite and goethite, cementing crater fill sediments into cohesive layers. Saturation index (SI) and Eh/pH assessments identify that fluids evolved at White Island are undersaturated with respect to the mineral phases present in the Fe-rich subsurface layers. Formation of the Fe-rich subsurface layers is most likely related to the transition between atmospheric gases and/or meteoric water mixing with hydrothermal fluids. This transition zone creates an environment conducive to forming jarosite and goethite forming in the same layer. Additionally, subsurface sediments including the Fe-rich layers show a consistent organic carbon isotopic signature of -23 ‰. Microscopic investigations confirm diatoms and microbes are present in the subsurface Fe-rich layers. The full extent of microbial activity in relation to the Fe-rich layers at White Island still requires further investigation. Based on chemical extractions for isotopic analyses, Fe-rich layers are shown to preserve δ¹³C signatures indicative of microbial life. Interface zones such as those identified in the hydrothermal environment at White Island can create metal-rich deposits and habitable/preservative microbial environments as well as affecting the macroscopic dynamics of volcanic and epithermal systems. |
format |
Other/Unknown Material |
author |
Win, Noel Antony |
author_facet |
Win, Noel Antony |
author_sort |
Win, Noel Antony |
title |
Formation of Fe-rich subsurface precipitate layers on White Island, New Zealand |
title_short |
Formation of Fe-rich subsurface precipitate layers on White Island, New Zealand |
title_full |
Formation of Fe-rich subsurface precipitate layers on White Island, New Zealand |
title_fullStr |
Formation of Fe-rich subsurface precipitate layers on White Island, New Zealand |
title_full_unstemmed |
Formation of Fe-rich subsurface precipitate layers on White Island, New Zealand |
title_sort |
formation of fe-rich subsurface precipitate layers on white island, new zealand |
publisher |
University of Canterbury. Geological Sciences |
publishDate |
2014 |
url |
http://hdl.handle.net/10092/9660 https://doi.org/10.26021/7944 |
long_lat |
ENVELOPE(-128.761,-128.761,52.837,52.837) ENVELOPE(167.167,167.167,-77.533,-77.533) ENVELOPE(48.583,48.583,-66.733,-66.733) |
geographic |
Bay of Plenty Main Crater New Zealand White Island |
geographic_facet |
Bay of Plenty Main Crater New Zealand White Island |
genre |
White Island |
genre_facet |
White Island |
op_relation |
NZCU http://hdl.handle.net/10092/9660 http://dx.doi.org/10.26021/7944 |
op_rights |
Copyright Noel Antony Win https://canterbury.libguides.com/rights/theses |
op_doi |
https://doi.org/10.26021/7944 |
_version_ |
1766233954615033856 |