Speleothems as indicators of wet and dry periods
Calcareous speleothems provide a record of dripwater composition which in turn is a function of climatic conditions. The historical focus of speleothem palaeoclimate studies has been on the derivation of palaeotemperatures through oxygen isotope studies. However, it is now realized that water availa...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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University of South Florida Libraries
2007-07-01
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| Series: | International Journal of Speleology |
| Subjects: | |
| Online Access: | http://www.ijs.speleo.it/pdf/66.549.36(2)_Fairchild_and_McMillan.pdf |
| _version_ | 1818846996192034816 |
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| author | Ian John Fairchild Emily Anne McMillan |
| author_facet | Ian John Fairchild Emily Anne McMillan |
| author_sort | Ian John Fairchild |
| collection | DOAJ |
| description | Calcareous speleothems provide a record of dripwater composition which in turn is a function of climatic conditions. The historical focus of speleothem palaeoclimate studies has been on the derivation of palaeotemperatures through oxygen isotope studies. However, it is now realized that water availability is a more generally important control on their characteristics. Growth rate and growth morphology in principle should give rise to recognizable changes at low flow. However, accidental plumbing effects during aquifer evolution, can also lead to variations in water supply and it is not easy to distinguish these effects. In areas where there is a strong amount effect on the δ18O composition of atmospheric precipitation, the speleothem δ18O composition can be a direct (and inverse) function of rainfall. High-resolution methods are now available to distinguish the composition and relative abundance of winter and summer precipitation in speleothems which formed from drips of seasonally-varying composition. Two seasonallyvarying processes can be responsible for significant geochemical effects during the year. Seasonal (normally summer) dryness enhances CO2-degassing which leads to elevated δ13C, Mg/Ca and Sr/Ca in dripwaters, characteristics which are transferred to speleothems. The same effects can arise by enhanced degassing at low PCO2. High-resolution analysis can distinguish the seasonal processes and, where conducted at several time intervals, allows a more confident interpretation of longer-term records. |
| first_indexed | 2024-12-19T05:54:25Z |
| format | Article |
| id | doaj.art-8f4cfd4563c442d6a242133bb5d772e0 |
| institution | Directory Open Access Journal |
| issn | 0392-6672 1827-806X |
| language | English |
| last_indexed | 2024-12-19T05:54:25Z |
| publishDate | 2007-07-01 |
| publisher | University of South Florida Libraries |
| record_format | Article |
| series | International Journal of Speleology |
| spelling | doaj.art-8f4cfd4563c442d6a242133bb5d772e02022-12-21T20:33:30ZengUniversity of South Florida LibrariesInternational Journal of Speleology0392-66721827-806X2007-07-013626974Speleothems as indicators of wet and dry periodsIan John FairchildEmily Anne McMillanCalcareous speleothems provide a record of dripwater composition which in turn is a function of climatic conditions. The historical focus of speleothem palaeoclimate studies has been on the derivation of palaeotemperatures through oxygen isotope studies. However, it is now realized that water availability is a more generally important control on their characteristics. Growth rate and growth morphology in principle should give rise to recognizable changes at low flow. However, accidental plumbing effects during aquifer evolution, can also lead to variations in water supply and it is not easy to distinguish these effects. In areas where there is a strong amount effect on the δ18O composition of atmospheric precipitation, the speleothem δ18O composition can be a direct (and inverse) function of rainfall. High-resolution methods are now available to distinguish the composition and relative abundance of winter and summer precipitation in speleothems which formed from drips of seasonally-varying composition. Two seasonallyvarying processes can be responsible for significant geochemical effects during the year. Seasonal (normally summer) dryness enhances CO2-degassing which leads to elevated δ13C, Mg/Ca and Sr/Ca in dripwaters, characteristics which are transferred to speleothems. The same effects can arise by enhanced degassing at low PCO2. High-resolution analysis can distinguish the seasonal processes and, where conducted at several time intervals, allows a more confident interpretation of longer-term records.http://www.ijs.speleo.it/pdf/66.549.36(2)_Fairchild_and_McMillan.pdfspeleothemspalaeohydrologystable isotopestrace elements |
| spellingShingle | Ian John Fairchild Emily Anne McMillan Speleothems as indicators of wet and dry periods International Journal of Speleology speleothems palaeohydrology stable isotopes trace elements |
| title | Speleothems as indicators of wet and dry periods |
| title_full | Speleothems as indicators of wet and dry periods |
| title_fullStr | Speleothems as indicators of wet and dry periods |
| title_full_unstemmed | Speleothems as indicators of wet and dry periods |
| title_short | Speleothems as indicators of wet and dry periods |
| title_sort | speleothems as indicators of wet and dry periods |
| topic | speleothems palaeohydrology stable isotopes trace elements |
| url | http://www.ijs.speleo.it/pdf/66.549.36(2)_Fairchild_and_McMillan.pdf |
| work_keys_str_mv | AT ianjohnfairchild speleothemsasindicatorsofwetanddryperiods AT emilyannemcmillan speleothemsasindicatorsofwetanddryperiods |