{"id":{"repo_id":"uwo","oai_identifier":"oai:uwo.scholaris.ca:20.500.14721/36977"},"canonical_url":"https://search.dev.ndltd.org/etd/uwo/oai:uwo.scholaris.ca:20.500.14721/36977","repository":{"repo_id":"uwo","name":"Western University","base_url":"https://uwo.scholaris.ca/server/oai/request"},"display":{"title":"Isotopic Fingerprinting of Shallow and Deep Groundwaters in Southwestern Ontario and its Applications to Abandoned Well Remediation","abstract":"Abandoned hydrocarbon wells in southwestern Ontario can act as conduits for Sulphur water, brines, and hydrocarbons from deep Paleozoic bedrock aquifers. Such leakage may pose a threat to shallow groundwater and the environment. Cost-effective plugging of these wells requires knowledge of the sources of the leaking fluids. This study characterizes the isotopic compositions (δ18OH2O, δ2HH2O, δ34SSO4, δ18OSO4, δ13CDIC, 87Sr/86Sr) of groundwaters in the region, which are distinct in different bedrock formations. A Bayesian mixing model was applied to these data to develop a tool for identifying the source(s) of leaking fluids. The geochemical data also improve our understanding of groundwater origin and evolution. Shallow (~<350m) aquifers are recharged by recent meteoric water. At greater depths, brine aquifers contain residual evaporated Paleozoic seawater, modified by rock-water interaction and mixing with meteoric water. These brines are likely related to long-distance fluid migration from deeper portions of the adjacent Michigan and Appalachian basins.","abstract_html":"Abandoned hydrocarbon wells in southwestern Ontario can act as conduits for Sulphur water, brines, and hydrocarbons from deep Paleozoic bedrock aquifers. Such leakage may pose a threat to shallow groundwater and the environment. Cost-effective plugging of these wells requires knowledge of the sources of the leaking fluids. This study characterizes the isotopic compositions (δ18OH2O, δ2HH2O, δ34SSO4, δ18OSO4, δ13CDIC, 87Sr/86Sr) of groundwaters in the region, which are distinct in different bedrock formations. A Bayesian mixing model was applied to these data to develop a tool for identifying the source(s) of leaking fluids. The geochemical data also improve our understanding of groundwater origin and evolution. Shallow (~&lt;350m) aquifers are recharged by recent meteoric water. At greater depths, brine aquifers contain residual evaporated Paleozoic seawater, modified by rock-water interaction and mixing with meteoric water. These brines are likely related to long-distance fluid migration from deeper portions of the adjacent Michigan and Appalachian basins.","abstract_has_math":false,"creators":["Skuce, Mitchell E"],"institution":"The University of Western Ontario","degree_name":"M Sc","degree_level":null,"degree_discipline":"Geology","degree_department":null,"school":null,"contributors":[],"advisors":["Fred Longstaffe"],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-03-14","date_published":"2014-03-14","updated_at":"2026-07-27T21:56:01Z","subjects":["Leaking wells","stable isotopes","geochemistry","hydrogeology","brines","SIAR","mixing model","groundwater evolution","southwestern Ontario"],"languages":["en_ca"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/20.500.14721/36977","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Fred Longstaffe"]},{"key":"dc:creator","label":"Author","values":["Skuce, Mitchell E"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2025-07-10T21:28:08Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2025-07-10T21:28:08Z"]},{"key":"dc:date.issued","label":"Date","values":["2014-03-14"]},{"key":"dc:publisher","label":"Institution","values":["The University of Western Ontario"]},{"key":"dc:type","label":"Dc Type","values":["thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Geology"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M Sc"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Leaking wells","stable isotopes","geochemistry","hydrogeology","brines","SIAR","mixing model","groundwater evolution","southwestern Ontario"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en_ca"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/20.500.14721/36977"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The thesis cover page in the PDF document includes references to Western University’s previous institutional repository platform, known as Scholarship@Western, and links to that platform (beginning with ir.lib.uwo.ca). In citing or referring to this thesis, use the DOI or handle from this page instead. Sample citation: Author name, \"Thesis title.\" (Year). Western University Open Repository. https://doi.org/10.71858/123456."]},{"key":"dc:description.abstract","label":"Abstract","values":["Abandoned hydrocarbon wells in southwestern Ontario can act as conduits for Sulphur water, brines, and hydrocarbons from deep Paleozoic bedrock aquifers. Such leakage may pose a threat to shallow groundwater and the environment. Cost-effective plugging of these wells requires knowledge of the sources of the leaking fluids. This study characterizes the isotopic compositions (δ18OH2O, δ2HH2O, δ34SSO4, δ18OSO4, δ13CDIC, 87Sr/86Sr) of groundwaters in the region, which are distinct in different bedrock formations. A Bayesian mixing model was applied to these data to develop a tool for identifying the source(s) of leaking fluids. The geochemical data also improve our understanding of groundwater origin and evolution. Shallow (~<350m) aquifers are recharged by recent meteoric water. At greater depths, brine aquifers contain residual evaporated Paleozoic seawater, modified by rock-water interaction and mixing with meteoric water. These brines are likely related to long-distance fluid migration from deeper portions of the adjacent Michigan and Appalachian basins."]},{"key":"dc:title","label":"Title","values":["Isotopic Fingerprinting of Shallow and Deep Groundwaters in Southwestern Ontario and its Applications to Abandoned Well Remediation"]}]}],"canonical_facts":{"dc:contributor.advisor":["Fred Longstaffe"],"dc:creator":["Skuce, Mitchell E"],"dc:date.accessioned":["2025-07-10T21:28:08Z"],"dc:date.available":["2025-07-10T21:28:08Z"],"dc:date.issued":["2014-03-14"],"dc:description":["The thesis cover page in the PDF document includes references to Western University’s previous institutional repository platform, known as Scholarship@Western, and links to that platform (beginning with ir.lib.uwo.ca). In citing or referring to this thesis, use the DOI or handle from this page instead. Sample citation: Author name, \"Thesis title.\" (Year). Western University Open Repository. https://doi.org/10.71858/123456."],"dc:description.abstract":["Abandoned hydrocarbon wells in southwestern Ontario can act as conduits for Sulphur water, brines, and hydrocarbons from deep Paleozoic bedrock aquifers. Such leakage may pose a threat to shallow groundwater and the environment. Cost-effective plugging of these wells requires knowledge of the sources of the leaking fluids. This study characterizes the isotopic compositions (δ18OH2O, δ2HH2O, δ34SSO4, δ18OSO4, δ13CDIC, 87Sr/86Sr) of groundwaters in the region, which are distinct in different bedrock formations. A Bayesian mixing model was applied to these data to develop a tool for identifying the source(s) of leaking fluids. The geochemical data also improve our understanding of groundwater origin and evolution. Shallow (~<350m) aquifers are recharged by recent meteoric water. At greater depths, brine aquifers contain residual evaporated Paleozoic seawater, modified by rock-water interaction and mixing with meteoric water. These brines are likely related to long-distance fluid migration from deeper portions of the adjacent Michigan and Appalachian basins."],"dc:identifier.uri":["https://hdl.handle.net/20.500.14721/36977"],"dc:language.iso":["en_ca"],"dc:publisher":["The University of Western Ontario"],"dc:subject":["Leaking wells","stable isotopes","geochemistry","hydrogeology","brines","SIAR","mixing model","groundwater evolution","southwestern Ontario"],"dc:title":["Isotopic Fingerprinting of Shallow and Deep Groundwaters in Southwestern Ontario and its Applications to Abandoned Well Remediation"],"dc:type":["thesis"],"thesis:degree_discipline":["Geology"],"thesis:degree_name":["M Sc"]},"updated_at":"2026-07-27T21:56:01Z"}