Deep Earth volatile cycles as revealed by basalt chemistry
Earth’s volatiles (e.g. CO$_2$ and H$_2$O) are thought to be stored largely in the interior of the planet. The partitioning of these volatile elements between Earth’s surface and interior controls the evolution of our atmosphere and oceans, acting as a regulator on our planet’s long term climate. Ba...
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ftunivcam:oai:www.repository.cam.ac.uk:1810/292863 2023-07-30T04:04:23+02:00 Deep Earth volatile cycles as revealed by basalt chemistry Matthews, Simon William 2019-05-15T16:12:07Z application/pdf https://doi.org/10.17863/CAM.40015 https://www.repository.cam.ac.uk/handle/1810/292863 en eng St Catharine's Earth Sciences University of Cambridge doi:10.17863/CAM.40015 https://www.repository.cam.ac.uk/handle/1810/292863 Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/ mantle mantle volatiles basalt geochemistry Deep Earth carbon water mantle temperature mantle lithology olivine melt inclusions degassing mixing Iceland mantle plume Thesis Doctoral Doctor of Philosophy (PhD) PhD in Earth Sciences 2019 ftunivcam https://doi.org/10.17863/CAM.40015 2023-07-10T21:55:53Z Earth’s volatiles (e.g. CO$_2$ and H$_2$O) are thought to be stored largely in the interior of the planet. The partitioning of these volatile elements between Earth’s surface and interior controls the evolution of our atmosphere and oceans, acting as a regulator on our planet’s long term climate. Basalt geochemistry is our most direct probe of Earth’s convecting mantle, however the tendency of volatile elements to form vapour phases deep within volcanic systems obscures the mantle volatile signals inherited by basalts. This thesis explores the extent to which basalts may preserve mantle volatile signals, places new constraints on volatile heterogeneity within the Icelandic plume, and considers the role of mantle convection in establishing deep Earth volatile cycles. Volatile- trace element systematics in suites of basaltic glass and melt inclusions have been widely used to infer volatile abundances in the depleted mantle, but have resulted in a large diversity of estimates. In this thesis a new statistical treatment of such datasets is developed, using simple numerical models for concurrent magma mixing and degassing. It is demonstrated that the role of magma degassing was previously underestimated, and the variability in apparent mantle volatile concentrations is largely a result of variability in magma mixing and degassing. Using a large new dataset of Icelandic melt inclusions sampling diverse mantle components, alongside a compilation of existing suites, the gross structure of the global melt inclusion array is shown to be controlled by magma degassing and olivine decrepitation. By applying the new statistical treatment of the data developed here, the presence of at least three mantle components with distinct volatile chemistry are demonstrated to contribute Icelandic magmas. With a novel combination of geophysical and geochemical constraints, the thermal structure and mineralogy of the melting region beneath Iceland is constrained. The role of mineralogical heterogeneity in the long term storage of mantle ... Doctoral or Postdoctoral Thesis Iceland Apollo - University of Cambridge Repository |
institution |
Open Polar |
collection |
Apollo - University of Cambridge Repository |
op_collection_id |
ftunivcam |
language |
English |
topic |
mantle mantle volatiles basalt geochemistry Deep Earth carbon water mantle temperature mantle lithology olivine melt inclusions degassing mixing Iceland mantle plume |
spellingShingle |
mantle mantle volatiles basalt geochemistry Deep Earth carbon water mantle temperature mantle lithology olivine melt inclusions degassing mixing Iceland mantle plume Matthews, Simon William Deep Earth volatile cycles as revealed by basalt chemistry |
topic_facet |
mantle mantle volatiles basalt geochemistry Deep Earth carbon water mantle temperature mantle lithology olivine melt inclusions degassing mixing Iceland mantle plume |
description |
Earth’s volatiles (e.g. CO$_2$ and H$_2$O) are thought to be stored largely in the interior of the planet. The partitioning of these volatile elements between Earth’s surface and interior controls the evolution of our atmosphere and oceans, acting as a regulator on our planet’s long term climate. Basalt geochemistry is our most direct probe of Earth’s convecting mantle, however the tendency of volatile elements to form vapour phases deep within volcanic systems obscures the mantle volatile signals inherited by basalts. This thesis explores the extent to which basalts may preserve mantle volatile signals, places new constraints on volatile heterogeneity within the Icelandic plume, and considers the role of mantle convection in establishing deep Earth volatile cycles. Volatile- trace element systematics in suites of basaltic glass and melt inclusions have been widely used to infer volatile abundances in the depleted mantle, but have resulted in a large diversity of estimates. In this thesis a new statistical treatment of such datasets is developed, using simple numerical models for concurrent magma mixing and degassing. It is demonstrated that the role of magma degassing was previously underestimated, and the variability in apparent mantle volatile concentrations is largely a result of variability in magma mixing and degassing. Using a large new dataset of Icelandic melt inclusions sampling diverse mantle components, alongside a compilation of existing suites, the gross structure of the global melt inclusion array is shown to be controlled by magma degassing and olivine decrepitation. By applying the new statistical treatment of the data developed here, the presence of at least three mantle components with distinct volatile chemistry are demonstrated to contribute Icelandic magmas. With a novel combination of geophysical and geochemical constraints, the thermal structure and mineralogy of the melting region beneath Iceland is constrained. The role of mineralogical heterogeneity in the long term storage of mantle ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Matthews, Simon William |
author_facet |
Matthews, Simon William |
author_sort |
Matthews, Simon William |
title |
Deep Earth volatile cycles as revealed by basalt chemistry |
title_short |
Deep Earth volatile cycles as revealed by basalt chemistry |
title_full |
Deep Earth volatile cycles as revealed by basalt chemistry |
title_fullStr |
Deep Earth volatile cycles as revealed by basalt chemistry |
title_full_unstemmed |
Deep Earth volatile cycles as revealed by basalt chemistry |
title_sort |
deep earth volatile cycles as revealed by basalt chemistry |
publisher |
St Catharine's |
publishDate |
2019 |
url |
https://doi.org/10.17863/CAM.40015 https://www.repository.cam.ac.uk/handle/1810/292863 |
genre |
Iceland |
genre_facet |
Iceland |
op_relation |
doi:10.17863/CAM.40015 https://www.repository.cam.ac.uk/handle/1810/292863 |
op_rights |
Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.17863/CAM.40015 |
_version_ |
1772815795299024896 |