GAS HYDRATES AND MAGNETISM: COMPARATIVE GEOLOGICAL SETTINGS FOR DIAGENETIC ANALYSIS
Geochemical processes associated with gas hydrate formation lead to the growth of iron sulphides which have a geophysically-measurable magnetic signature. Detailed magnetic investigation, complemented by petrological observations, were undertaken on cores from a permafrost setting, the Mackenzie Del...
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ftunivbritcolcir:oai:circle.library.ubc.ca:2429/1046 2023-05-15T17:09:31+02:00 GAS HYDRATES AND MAGNETISM: COMPARATIVE GEOLOGICAL SETTINGS FOR DIAGENETIC ANALYSIS Esteban, Lionel Enkin, Randolph J. Hamilton, Tark. University of British Columbia. Department of Chemical and Biological Engineering International Conference on Gas Hydrates (6th : 2008 : Vancouver, B.C.) Bengal, Bay of Mackenzie River Delta (N.W.T. and Yukon) Northwest, Pacific 2008-07 9657388 bytes application/pdf http://hdl.handle.net/2429/1046 eng eng Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/ CC-BY-NC-ND Gas hydrates Magnetism Mallik Solute exclusion Iron-sulphides Cascadia margin Sediments Bay of Bengal Text Conference Paper 2008 ftunivbritcolcir 2019-10-15T17:43:28Z Geochemical processes associated with gas hydrate formation lead to the growth of iron sulphides which have a geophysically-measurable magnetic signature. Detailed magnetic investigation, complemented by petrological observations, were undertaken on cores from a permafrost setting, the Mackenzie Delta (Canadian Northwest Territories) Mallik region, and two marine settings, IODP Expedition 311 cores from the Cascadia margin off Vancouver Island and the Indian National Gas Hydrate Program Expedition 1 from the Bengal Fan. Stratigraphic profiles of the fine scale variations in bulk magnetic measurements correspond to changes in lithology, grain size and pore fluid geochemistry which can be correlated on local to regional scales. The lowest values of magnetic susceptibility are observed where iron has been reduced to paramagnetic pyrite, formed in settings with high methane and sulphate or sulphide flux, such as at methane vents. High magnetic susceptibility values are observed in sediments which contain detrital magnetite, for example from glacial deposits, which has survived diagenesis. Other high magnetic susceptibility values are observed in sediments in which the ferrimagnetic iron-sulphide minerals greigite or smythite have been diagenetically introduced. These minerals are mostly found outside the sediments which host gas hydrate. The mineral textures and compositions indicate rapid disequilibrium crystallization. The unique physical and geochemical properties of the environments where gas hydrates form, including the availability of methane to fuel microbiological activity and the concentration of pore water solutes during gas hydrate formation, lead to iron sulphide precipitation from solute-rich brines. Magnetic surveying techniques help delineate anomalies related to gas hydrate deposits and the diagenesis of magnetic iron minerals related to their formation. Detailed core logging measurements and laboratory analyses of magnetic properties provide direct ties to original lithology, petrophysical properties and diagenesis caused by gas hydrate formation. Non UBC Unreviewed Conference Object Mackenzie Delta Mackenzie river Northwest Territories permafrost Yukon University of British Columbia: cIRcle - UBC's Information Repository Indian Mackenzie Delta ENVELOPE(-136.672,-136.672,68.833,68.833) Mackenzie River Northwest Territories Pacific Yukon |
institution |
Open Polar |
collection |
University of British Columbia: cIRcle - UBC's Information Repository |
op_collection_id |
ftunivbritcolcir |
language |
English |
topic |
Gas hydrates Magnetism Mallik Solute exclusion Iron-sulphides Cascadia margin Sediments Bay of Bengal |
spellingShingle |
Gas hydrates Magnetism Mallik Solute exclusion Iron-sulphides Cascadia margin Sediments Bay of Bengal Esteban, Lionel Enkin, Randolph J. Hamilton, Tark. GAS HYDRATES AND MAGNETISM: COMPARATIVE GEOLOGICAL SETTINGS FOR DIAGENETIC ANALYSIS |
topic_facet |
Gas hydrates Magnetism Mallik Solute exclusion Iron-sulphides Cascadia margin Sediments Bay of Bengal |
description |
Geochemical processes associated with gas hydrate formation lead to the growth of iron sulphides which have a geophysically-measurable magnetic signature. Detailed magnetic investigation, complemented by petrological observations, were undertaken on cores from a permafrost setting, the Mackenzie Delta (Canadian Northwest Territories) Mallik region, and two marine settings, IODP Expedition 311 cores from the Cascadia margin off Vancouver Island and the Indian National Gas Hydrate Program Expedition 1 from the Bengal Fan. Stratigraphic profiles of the fine scale variations in bulk magnetic measurements correspond to changes in lithology, grain size and pore fluid geochemistry which can be correlated on local to regional scales. The lowest values of magnetic susceptibility are observed where iron has been reduced to paramagnetic pyrite, formed in settings with high methane and sulphate or sulphide flux, such as at methane vents. High magnetic susceptibility values are observed in sediments which contain detrital magnetite, for example from glacial deposits, which has survived diagenesis. Other high magnetic susceptibility values are observed in sediments in which the ferrimagnetic iron-sulphide minerals greigite or smythite have been diagenetically introduced. These minerals are mostly found outside the sediments which host gas hydrate. The mineral textures and compositions indicate rapid disequilibrium crystallization. The unique physical and geochemical properties of the environments where gas hydrates form, including the availability of methane to fuel microbiological activity and the concentration of pore water solutes during gas hydrate formation, lead to iron sulphide precipitation from solute-rich brines. Magnetic surveying techniques help delineate anomalies related to gas hydrate deposits and the diagenesis of magnetic iron minerals related to their formation. Detailed core logging measurements and laboratory analyses of magnetic properties provide direct ties to original lithology, petrophysical properties and diagenesis caused by gas hydrate formation. Non UBC Unreviewed |
author2 |
University of British Columbia. Department of Chemical and Biological Engineering International Conference on Gas Hydrates (6th : 2008 : Vancouver, B.C.) |
format |
Conference Object |
author |
Esteban, Lionel Enkin, Randolph J. Hamilton, Tark. |
author_facet |
Esteban, Lionel Enkin, Randolph J. Hamilton, Tark. |
author_sort |
Esteban, Lionel |
title |
GAS HYDRATES AND MAGNETISM: COMPARATIVE GEOLOGICAL SETTINGS FOR DIAGENETIC ANALYSIS |
title_short |
GAS HYDRATES AND MAGNETISM: COMPARATIVE GEOLOGICAL SETTINGS FOR DIAGENETIC ANALYSIS |
title_full |
GAS HYDRATES AND MAGNETISM: COMPARATIVE GEOLOGICAL SETTINGS FOR DIAGENETIC ANALYSIS |
title_fullStr |
GAS HYDRATES AND MAGNETISM: COMPARATIVE GEOLOGICAL SETTINGS FOR DIAGENETIC ANALYSIS |
title_full_unstemmed |
GAS HYDRATES AND MAGNETISM: COMPARATIVE GEOLOGICAL SETTINGS FOR DIAGENETIC ANALYSIS |
title_sort |
gas hydrates and magnetism: comparative geological settings for diagenetic analysis |
publishDate |
2008 |
url |
http://hdl.handle.net/2429/1046 |
op_coverage |
Bengal, Bay of Mackenzie River Delta (N.W.T. and Yukon) Northwest, Pacific |
long_lat |
ENVELOPE(-136.672,-136.672,68.833,68.833) |
geographic |
Indian Mackenzie Delta Mackenzie River Northwest Territories Pacific Yukon |
geographic_facet |
Indian Mackenzie Delta Mackenzie River Northwest Territories Pacific Yukon |
genre |
Mackenzie Delta Mackenzie river Northwest Territories permafrost Yukon |
genre_facet |
Mackenzie Delta Mackenzie river Northwest Territories permafrost Yukon |
op_rights |
Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/ |
op_rightsnorm |
CC-BY-NC-ND |
_version_ |
1766065624108236800 |