Regional metamorphism and hydrothermal alteration related to Miocene submarine volcanism (‘green tuff’) in the Yurihara oil and gas field, northwest Honshu Island, Japan
Abstract Alteration of reservoir rocks in the Yurihara Oil and Gas Field, hereafter referred to as the ‘Yurihara field’, have been examined by using samples from six wells. These rocks are basalts in the lowermost part of the basin‐fills (‘green tuff’ Formation). These basalts were produced in many...
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crwiley:10.1111/j.1440-1738.1993.tb00091.x 2024-06-02T08:13:27+00:00 Regional metamorphism and hydrothermal alteration related to Miocene submarine volcanism (‘green tuff’) in the Yurihara oil and gas field, northwest Honshu Island, Japan Yagi, Masahiko 1993 http://dx.doi.org/10.1111/j.1440-1738.1993.tb00091.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1440-1738.1993.tb00091.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1440-1738.1993.tb00091.x en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Island Arc volume 2, issue 4, page 240-261 ISSN 1038-4871 1440-1738 journal-article 1993 crwiley https://doi.org/10.1111/j.1440-1738.1993.tb00091.x 2024-05-03T11:59:41Z Abstract Alteration of reservoir rocks in the Yurihara Oil and Gas Field, hereafter referred to as the ‘Yurihara field’, have been examined by using samples from six wells. These rocks are basalts in the lowermost part of the basin‐fills (‘green tuff’ Formation). These basalts were produced in many eruptions in a submarine environment during the early to middle Miocene, and they underwent continuous intensive alteration genetically associated with Miocene submarine volcanism. The alteration of the basalts is of two types: low grade metamorphism and hydrothermal. The former belongs to the type of ocean floor metamorphism and comprises two subgroups: zeolite (zone I) and prehnite‐pumpellyite (zones IIa: vein and amygdule occurrence, and IIb: replacing plagioclase). The latter is characterized by potassic metasomatism accompanied by adularia, quartz and calcite veins (zones IIIa: center and IIIb: margin of the metasomatism). This overprints the low grade metamorphic alteration. The central zone of hydrothermal alteration coincides with a major estimated fault, so that fluids probably assent along the fault. The basalts erupted during 16.5‐15.5 Ma, determined by planktonic foraminifera assemblages of inter‐bedded shales, then underwent successive low grade metamorphism. In time, the hydrothermal alteration that overprints low grade metamorphism occurred. Adularia veins of the altered rocks located in the hydrothermal alteration zones (zone IIIa and IIIb) have been dated as 9 Ma determined by the K‐Ar method. This fact indicates that the activity of low grade metamorphism had already crossed the peak before hydrothermal alteration occurred at 9 Ma. The shape of isotherms of fluid inclusion homogenization temperatures (Th) and that of isolines of apparent salinity (Tm) almost coincide with each other, and these also coincide with the distribution of hydrothermal alteration (zones IIIa and IIIb). This indicates that the fluid inclusions formed at the same time as ascending fluids produced the potassic metasomatism. The ... Article in Journal/Newspaper Planktonic foraminifera Wiley Online Library Island Arc 2 4 240 261 |
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English |
description |
Abstract Alteration of reservoir rocks in the Yurihara Oil and Gas Field, hereafter referred to as the ‘Yurihara field’, have been examined by using samples from six wells. These rocks are basalts in the lowermost part of the basin‐fills (‘green tuff’ Formation). These basalts were produced in many eruptions in a submarine environment during the early to middle Miocene, and they underwent continuous intensive alteration genetically associated with Miocene submarine volcanism. The alteration of the basalts is of two types: low grade metamorphism and hydrothermal. The former belongs to the type of ocean floor metamorphism and comprises two subgroups: zeolite (zone I) and prehnite‐pumpellyite (zones IIa: vein and amygdule occurrence, and IIb: replacing plagioclase). The latter is characterized by potassic metasomatism accompanied by adularia, quartz and calcite veins (zones IIIa: center and IIIb: margin of the metasomatism). This overprints the low grade metamorphic alteration. The central zone of hydrothermal alteration coincides with a major estimated fault, so that fluids probably assent along the fault. The basalts erupted during 16.5‐15.5 Ma, determined by planktonic foraminifera assemblages of inter‐bedded shales, then underwent successive low grade metamorphism. In time, the hydrothermal alteration that overprints low grade metamorphism occurred. Adularia veins of the altered rocks located in the hydrothermal alteration zones (zone IIIa and IIIb) have been dated as 9 Ma determined by the K‐Ar method. This fact indicates that the activity of low grade metamorphism had already crossed the peak before hydrothermal alteration occurred at 9 Ma. The shape of isotherms of fluid inclusion homogenization temperatures (Th) and that of isolines of apparent salinity (Tm) almost coincide with each other, and these also coincide with the distribution of hydrothermal alteration (zones IIIa and IIIb). This indicates that the fluid inclusions formed at the same time as ascending fluids produced the potassic metasomatism. The ... |
format |
Article in Journal/Newspaper |
author |
Yagi, Masahiko |
spellingShingle |
Yagi, Masahiko Regional metamorphism and hydrothermal alteration related to Miocene submarine volcanism (‘green tuff’) in the Yurihara oil and gas field, northwest Honshu Island, Japan |
author_facet |
Yagi, Masahiko |
author_sort |
Yagi, Masahiko |
title |
Regional metamorphism and hydrothermal alteration related to Miocene submarine volcanism (‘green tuff’) in the Yurihara oil and gas field, northwest Honshu Island, Japan |
title_short |
Regional metamorphism and hydrothermal alteration related to Miocene submarine volcanism (‘green tuff’) in the Yurihara oil and gas field, northwest Honshu Island, Japan |
title_full |
Regional metamorphism and hydrothermal alteration related to Miocene submarine volcanism (‘green tuff’) in the Yurihara oil and gas field, northwest Honshu Island, Japan |
title_fullStr |
Regional metamorphism and hydrothermal alteration related to Miocene submarine volcanism (‘green tuff’) in the Yurihara oil and gas field, northwest Honshu Island, Japan |
title_full_unstemmed |
Regional metamorphism and hydrothermal alteration related to Miocene submarine volcanism (‘green tuff’) in the Yurihara oil and gas field, northwest Honshu Island, Japan |
title_sort |
regional metamorphism and hydrothermal alteration related to miocene submarine volcanism (‘green tuff’) in the yurihara oil and gas field, northwest honshu island, japan |
publisher |
Wiley |
publishDate |
1993 |
url |
http://dx.doi.org/10.1111/j.1440-1738.1993.tb00091.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1440-1738.1993.tb00091.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1440-1738.1993.tb00091.x |
genre |
Planktonic foraminifera |
genre_facet |
Planktonic foraminifera |
op_source |
Island Arc volume 2, issue 4, page 240-261 ISSN 1038-4871 1440-1738 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/j.1440-1738.1993.tb00091.x |
container_title |
Island Arc |
container_volume |
2 |
container_issue |
4 |
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240 |
op_container_end_page |
261 |
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1800736965197299712 |