{"id":138,"date":"2020-11-18T16:03:22","date_gmt":"2020-11-18T16:03:22","guid":{"rendered":"https:\/\/books.gw-project.org\/introduction-to-isotopes-and-environmental-tracers-as-indicators-of-groundwater-flow\/chapter\/reconstructing-climatic-conditions\/"},"modified":"2020-12-12T17:08:53","modified_gmt":"2020-12-12T17:08:53","slug":"reconstructing-climatic-conditions","status":"publish","type":"chapter","link":"https:\/\/books.gw-project.org\/introduction-to-isotopes-and-environmental-tracers-as-indicators-of-groundwater-flow\/chapter\/reconstructing-climatic-conditions\/","title":{"raw":"3.8 Reconstructing Climatic Conditions","rendered":"3.8 Reconstructing Climatic Conditions"},"content":{"raw":"Environmental tracers can also be used for climatic reconstruction. Noble gases are particularly useful, as their atmospheric concentrations are constant, and so measured concentrations provide direct information on solubility. This is largely determined by the temperature at the water table at the time of recharge. 2<\/sup>H and 18<\/sup>O can also provide information on recharge, as isotopic ratios in rainfall are influenced by temperature, although for quantitative use, the relationship between isotope ratio and temperature needs to be independently determined at each field site. A small number of studies have also estimated past groundwater recharge rates from past changes in the chloride concentration of infiltrating water (e.g., Murphy et al., 1996).\r\n\r\nThe Great Hungarian Plain (Figure 40) consists of an upper Quaternary aquifer and a deeper Pliocene aquifer. Noble gas temperatures for these aquifer systems have been measured with Ne, Ar, Kr and Xe concentrations. Groundwater ages have been estimated using 14<\/sup>C, which provides the timescale for the climatic reconstruction. Samples with 14<\/sup>C ages less than 10,000 years have an average noble gas recharge temperature of 10.6 \u00b0C, which is close to the mean annual temperature in the recharge area under the current climate (11.4 \u00b0C). Noble gas temperatures at the glacial maxima (approximately 18,000 years ago) suggest an average mean annual temperature approximately 8.6\u00b0 lower than present (Figure 41). Temperatures preceding the glacial period (28,000 \u2013 35,000 years ago) were approximately 5\u00b0 lower than present. The 18<\/sup>O record shows a similar pattern, revealing depleted values in samples with 14<\/sup>C ages exceeding 10,000 years (Stute and Schlosser, 2000).\r\n\r\n[caption id=\"attachment_206\" align=\"alignnone\" width=\"998\"]\"Map Figure <\/strong>40<\/strong> - The Great Hungarian Plain (red area in map of Hungary (Wikimedia Commons, 2010. \u201cLocation of geographical macroregion of hu:Alf\u00f6ld (red) within subdivisions of Hungary based on Magyarorsz\u00e1g kist\u00e1jainak katasztere<\/a>\u201d by Miaow Miaow<\/a> is public domain), which has been the focus of palaeoclimate studies using groundwater isotopes and noble gases (Figure 41). The location of Hungary within Europe is shown in the image to the right.[\/caption]\r\n\r\n[caption id=\"attachment_207\" align=\"alignnone\" width=\"499\"]\"Noble Figure <\/strong>41<\/strong> - Noble gas derived palaeotemperatures and 18<\/sup>O ratios and 14<\/sup>C ages for groundwater from the Great Hungarian Plain. Samples with 14<\/sup>C ages less than 10,000 years have an average noble gas temperature of 10.6 \u00b0C. The noble gas temperature prior to the last glacial period (28,000 \u2013 35,000 years ago) was approximately 5\u00b0C lower than present, and at the glacial maxima (approximately 18,000 years ago) the temperature was 8-9\u00b0C lower than present. The 18<\/sup>O record shows a similar pattern, with depleted values in samples with 14<\/sup>C ages exceeding 10,000 years (After Stute and Schlosser, 2000).[\/caption]","rendered":"

Environmental tracers can also be used for climatic reconstruction. Noble gases are particularly useful, as their atmospheric concentrations are constant, and so measured concentrations provide direct information on solubility. This is largely determined by the temperature at the water table at the time of recharge. 2<\/sup>H and 18<\/sup>O can also provide information on recharge, as isotopic ratios in rainfall are influenced by temperature, although for quantitative use, the relationship between isotope ratio and temperature needs to be independently determined at each field site. A small number of studies have also estimated past groundwater recharge rates from past changes in the chloride concentration of infiltrating water (e.g., Murphy et al., 1996).<\/p>\n

The Great Hungarian Plain (Figure 40) consists of an upper Quaternary aquifer and a deeper Pliocene aquifer. Noble gas temperatures for these aquifer systems have been measured with Ne, Ar, Kr and Xe concentrations. Groundwater ages have been estimated using 14<\/sup>C, which provides the timescale for the climatic reconstruction. Samples with 14<\/sup>C ages less than 10,000 years have an average noble gas recharge temperature of 10.6 \u00b0C, which is close to the mean annual temperature in the recharge area under the current climate (11.4 \u00b0C). Noble gas temperatures at the glacial maxima (approximately 18,000 years ago) suggest an average mean annual temperature approximately 8.6\u00b0 lower than present (Figure 41). Temperatures preceding the glacial period (28,000 \u2013 35,000 years ago) were approximately 5\u00b0 lower than present. The 18<\/sup>O record shows a similar pattern, revealing depleted values in samples with 14<\/sup>C ages exceeding 10,000 years (Stute and Schlosser, 2000).<\/p>\n

\"Map
Figure <\/strong>40<\/strong> – The Great Hungarian Plain (red area in map of Hungary (Wikimedia Commons, 2010. \u201cLocation of geographical macroregion of hu:Alf\u00f6ld (red) within subdivisions of Hungary based on Magyarorsz\u00e1g kist\u00e1jainak katasztere<\/a>\u201d by Miaow Miaow<\/a> is public domain), which has been the focus of palaeoclimate studies using groundwater isotopes and noble gases (Figure 41). The location of Hungary within Europe is shown in the image to the right.<\/figcaption><\/figure>\n
\"Noble
Figure <\/strong>41<\/strong> – Noble gas derived palaeotemperatures and 18<\/sup>O ratios and 14<\/sup>C ages for groundwater from the Great Hungarian Plain. Samples with 14<\/sup>C ages less than 10,000 years have an average noble gas temperature of 10.6 \u00b0C. The noble gas temperature prior to the last glacial period (28,000 \u2013 35,000 years ago) was approximately 5\u00b0C lower than present, and at the glacial maxima (approximately 18,000 years ago) the temperature was 8-9\u00b0C lower than present. The 18<\/sup>O record shows a similar pattern, with depleted values in samples with 14<\/sup>C ages exceeding 10,000 years (After Stute and Schlosser, 2000).<\/figcaption><\/figure>\n","protected":false},"author":1,"menu_order":8,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-138","chapter","type-chapter","status-publish","hentry"],"part":127,"_links":{"self":[{"href":"https:\/\/books.gw-project.org\/introduction-to-isotopes-and-environmental-tracers-as-indicators-of-groundwater-flow\/wp-json\/pressbooks\/v2\/chapters\/138","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/books.gw-project.org\/introduction-to-isotopes-and-environmental-tracers-as-indicators-of-groundwater-flow\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/books.gw-project.org\/introduction-to-isotopes-and-environmental-tracers-as-indicators-of-groundwater-flow\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/books.gw-project.org\/introduction-to-isotopes-and-environmental-tracers-as-indicators-of-groundwater-flow\/wp-json\/wp\/v2\/users\/1"}],"version-history":[{"count":8,"href":"https:\/\/books.gw-project.org\/introduction-to-isotopes-and-environmental-tracers-as-indicators-of-groundwater-flow\/wp-json\/pressbooks\/v2\/chapters\/138\/revisions"}],"predecessor-version":[{"id":427,"href":"https:\/\/books.gw-project.org\/introduction-to-isotopes-and-environmental-tracers-as-indicators-of-groundwater-flow\/wp-json\/pressbooks\/v2\/chapters\/138\/revisions\/427"}],"part":[{"href":"https:\/\/books.gw-project.org\/introduction-to-isotopes-and-environmental-tracers-as-indicators-of-groundwater-flow\/wp-json\/pressbooks\/v2\/parts\/127"}],"metadata":[{"href":"https:\/\/books.gw-project.org\/introduction-to-isotopes-and-environmental-tracers-as-indicators-of-groundwater-flow\/wp-json\/pressbooks\/v2\/chapters\/138\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/books.gw-project.org\/introduction-to-isotopes-and-environmental-tracers-as-indicators-of-groundwater-flow\/wp-json\/wp\/v2\/media?parent=138"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/books.gw-project.org\/introduction-to-isotopes-and-environmental-tracers-as-indicators-of-groundwater-flow\/wp-json\/pressbooks\/v2\/chapter-type?post=138"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/books.gw-project.org\/introduction-to-isotopes-and-environmental-tracers-as-indicators-of-groundwater-flow\/wp-json\/wp\/v2\/contributor?post=138"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/books.gw-project.org\/introduction-to-isotopes-and-environmental-tracers-as-indicators-of-groundwater-flow\/wp-json\/wp\/v2\/license?post=138"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}