Assessment of the usefulness of lithic clasts from pyroclastic deposits for paleointensity determination
Paleomagnetic and rock magnetic measurements were carried out on lithic clasts found within pyroclastic deposits to assess their potential for paleointensity determinations. The use of multiple lithologies in a single paleointensity determination would provide confidence that the result is not biase...
| Main Authors: | , , , |
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| Format: | Journal article |
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2010
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| _version_ | 1797105237941551104 |
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| author | Paterson, G Muxworthy, A Roberts, A Niocaill, C |
| author_facet | Paterson, G Muxworthy, A Roberts, A Niocaill, C |
| author_sort | Paterson, G |
| collection | OXFORD |
| description | Paleomagnetic and rock magnetic measurements were carried out on lithic clasts found within pyroclastic deposits to assess their potential for paleointensity determinations. The use of multiple lithologies in a single paleointensity determination would provide confidence that the result is not biased by alteration within one lithology. Lithic clasts were sampled from three historically active volcanoes: Láscar in the Chilean Andes, Mt. St. Helens, United States, and Vesuvius, Italy. At Láscar, triple heating paleointensity experiments allow development of new selection criteria for lithic clasts found within pyroclastic deposits. Using these criteria, the Láscar data yield a mean paleointensity of 24.3 ± 1.3 μT (1σ, N = 26), which agrees well with the expected value of 24.0 μT. This indicates that pyroclastic rocks have promise for paleointensity determinations. Pyroclastics, however, still suffer from the range of problems associated with conventional paleointensity experiments on lava flows. Samples from Mt. St. Helens are strongly affected by multidomain (MD) behavior, which results in all samples failing to pass the paleointensity selection criteria. At Vesuvius, MD grains, magnetic interactions, and chemical remanent magnetizations contributed to failure of all paleointensity experiments. Rock magnetic analyses allow identification of the causes of failure of the paleointensity experiments. However, in this study, they have not provided adequate preselection criteria for identifying pyroclastics that are suitable for paleointensity determination. © Copyright 2010 by the American Geophysical Union. |
| first_indexed | 2024-03-07T06:44:38Z |
| format | Journal article |
| id | oxford-uuid:fa728a39-f154-481c-9e59-4606a5a1d599 |
| institution | University of Oxford |
| last_indexed | 2024-03-07T06:44:38Z |
| publishDate | 2010 |
| record_format | dspace |
| spelling | oxford-uuid:fa728a39-f154-481c-9e59-4606a5a1d5992022-03-27T13:05:57ZAssessment of the usefulness of lithic clasts from pyroclastic deposits for paleointensity determinationJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:fa728a39-f154-481c-9e59-4606a5a1d599Symplectic Elements at Oxford2010Paterson, GMuxworthy, ARoberts, ANiocaill, CPaleomagnetic and rock magnetic measurements were carried out on lithic clasts found within pyroclastic deposits to assess their potential for paleointensity determinations. The use of multiple lithologies in a single paleointensity determination would provide confidence that the result is not biased by alteration within one lithology. Lithic clasts were sampled from three historically active volcanoes: Láscar in the Chilean Andes, Mt. St. Helens, United States, and Vesuvius, Italy. At Láscar, triple heating paleointensity experiments allow development of new selection criteria for lithic clasts found within pyroclastic deposits. Using these criteria, the Láscar data yield a mean paleointensity of 24.3 ± 1.3 μT (1σ, N = 26), which agrees well with the expected value of 24.0 μT. This indicates that pyroclastic rocks have promise for paleointensity determinations. Pyroclastics, however, still suffer from the range of problems associated with conventional paleointensity experiments on lava flows. Samples from Mt. St. Helens are strongly affected by multidomain (MD) behavior, which results in all samples failing to pass the paleointensity selection criteria. At Vesuvius, MD grains, magnetic interactions, and chemical remanent magnetizations contributed to failure of all paleointensity experiments. Rock magnetic analyses allow identification of the causes of failure of the paleointensity experiments. However, in this study, they have not provided adequate preselection criteria for identifying pyroclastics that are suitable for paleointensity determination. © Copyright 2010 by the American Geophysical Union. |
| spellingShingle | Paterson, G Muxworthy, A Roberts, A Niocaill, C Assessment of the usefulness of lithic clasts from pyroclastic deposits for paleointensity determination |
| title | Assessment of the usefulness of lithic clasts from pyroclastic deposits for paleointensity determination |
| title_full | Assessment of the usefulness of lithic clasts from pyroclastic deposits for paleointensity determination |
| title_fullStr | Assessment of the usefulness of lithic clasts from pyroclastic deposits for paleointensity determination |
| title_full_unstemmed | Assessment of the usefulness of lithic clasts from pyroclastic deposits for paleointensity determination |
| title_short | Assessment of the usefulness of lithic clasts from pyroclastic deposits for paleointensity determination |
| title_sort | assessment of the usefulness of lithic clasts from pyroclastic deposits for paleointensity determination |
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