Quantified abundance of magnetofossils at the Paleocene–Eocene boundary from synchrotron-based transmission X-ray microscopy
The Paleocene–Eocene boundary (∼55.8 million years ago) is marked by an abrupt negative carbon isotope excursion (CIE) that coincides with an oxygen isotope decrease interpreted as the Paleocene–Eocene thermal maximum. Biogenic magnetite (Fe[subscript 3]O[subscript 4]) in the form of giant (micron-s...
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| Format: | Article |
| Language: | en_US |
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National Academy of Sciences (U.S.)
2016
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| Online Access: | http://hdl.handle.net/1721.1/102263 https://orcid.org/0000-0003-1676-3494 |
| _version_ | 1826215993321455616 |
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| author | Wang, Huapei Wang, Jun Chen-Wiegart, Yu-chen Karen Kent, Dennis V. |
| author2 | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences |
| author_facet | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Wang, Huapei Wang, Jun Chen-Wiegart, Yu-chen Karen Kent, Dennis V. |
| author_sort | Wang, Huapei |
| collection | MIT |
| description | The Paleocene–Eocene boundary (∼55.8 million years ago) is marked by an abrupt negative carbon isotope excursion (CIE) that coincides with an oxygen isotope decrease interpreted as the Paleocene–Eocene thermal maximum. Biogenic magnetite (Fe[subscript 3]O[subscript 4]) in the form of giant (micron-sized) spearhead-like and spindle-like magnetofossils, as well as nano-sized magnetotactic bacteria magnetosome chains, have been reported in clay-rich sediments in the New Jersey Atlantic Coastal Plain and were thought to account for the distinctive single-domain magnetic properties of these sediments. Uncalibrated strong field magnet extraction techniques have been typically used to provide material for scanning and transmission electron microscopic imaging of these magnetic particles, whose concentration in the natural sediment is thus difficult to quantify. In this study, we use a recently developed ultrahigh-resolution, synchrotron-based, full-field transmission X-ray microscope to study the iron-rich minerals within the clay sediment in their bulk state. We are able to estimate the total magnetization concentration of the giant biogenic magnetofossils to be only ∼10% of whole sediment. Along with previous rock magnetic studies on the CIE clay, we suggest that most of the magnetite in the clay occurs as isolated, near-equidimensional nanoparticles, a suggestion that points to a nonbiogenic origin, such as comet impact plume condensates in what may be very rapidly deposited CIE clays. |
| first_indexed | 2024-09-23T16:40:21Z |
| format | Article |
| id | mit-1721.1/102263 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T16:40:21Z |
| publishDate | 2016 |
| publisher | National Academy of Sciences (U.S.) |
| record_format | dspace |
| spelling | mit-1721.1/1022632022-10-03T07:31:49Z Quantified abundance of magnetofossils at the Paleocene–Eocene boundary from synchrotron-based transmission X-ray microscopy Wang, Huapei Wang, Jun Chen-Wiegart, Yu-chen Karen Kent, Dennis V. Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Wang, Huapei The Paleocene–Eocene boundary (∼55.8 million years ago) is marked by an abrupt negative carbon isotope excursion (CIE) that coincides with an oxygen isotope decrease interpreted as the Paleocene–Eocene thermal maximum. Biogenic magnetite (Fe[subscript 3]O[subscript 4]) in the form of giant (micron-sized) spearhead-like and spindle-like magnetofossils, as well as nano-sized magnetotactic bacteria magnetosome chains, have been reported in clay-rich sediments in the New Jersey Atlantic Coastal Plain and were thought to account for the distinctive single-domain magnetic properties of these sediments. Uncalibrated strong field magnet extraction techniques have been typically used to provide material for scanning and transmission electron microscopic imaging of these magnetic particles, whose concentration in the natural sediment is thus difficult to quantify. In this study, we use a recently developed ultrahigh-resolution, synchrotron-based, full-field transmission X-ray microscope to study the iron-rich minerals within the clay sediment in their bulk state. We are able to estimate the total magnetization concentration of the giant biogenic magnetofossils to be only ∼10% of whole sediment. Along with previous rock magnetic studies on the CIE clay, we suggest that most of the magnetite in the clay occurs as isolated, near-equidimensional nanoparticles, a suggestion that points to a nonbiogenic origin, such as comet impact plume condensates in what may be very rapidly deposited CIE clays. Rutgers University (Board of Governors Professor Research Fund) 2016-04-19T17:02:26Z 2016-04-19T17:02:26Z 2015-10 2015-06 Article http://purl.org/eprint/type/JournalArticle 0027-8424 1091-6490 http://hdl.handle.net/1721.1/102263 Wang, Huapei, Jun Wang, Yu-chen Karen Chen-Wiegart, and Dennis V. Kent. “Quantified Abundance of Magnetofossils at the Paleocene–Eocene Boundary from Synchrotron-Based Transmission X-Ray Microscopy.” Proc Natl Acad Sci USA 112, no. 41 (September 29, 2015): 12598–12603. https://orcid.org/0000-0003-1676-3494 en_US http://dx.doi.org/10.1073/pnas.1517475112 Proceedings of the National Academy of Sciences Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf National Academy of Sciences (U.S.) National Academy of Sciences (U.S.) |
| spellingShingle | Wang, Huapei Wang, Jun Chen-Wiegart, Yu-chen Karen Kent, Dennis V. Quantified abundance of magnetofossils at the Paleocene–Eocene boundary from synchrotron-based transmission X-ray microscopy |
| title | Quantified abundance of magnetofossils at the Paleocene–Eocene boundary from synchrotron-based transmission X-ray microscopy |
| title_full | Quantified abundance of magnetofossils at the Paleocene–Eocene boundary from synchrotron-based transmission X-ray microscopy |
| title_fullStr | Quantified abundance of magnetofossils at the Paleocene–Eocene boundary from synchrotron-based transmission X-ray microscopy |
| title_full_unstemmed | Quantified abundance of magnetofossils at the Paleocene–Eocene boundary from synchrotron-based transmission X-ray microscopy |
| title_short | Quantified abundance of magnetofossils at the Paleocene–Eocene boundary from synchrotron-based transmission X-ray microscopy |
| title_sort | quantified abundance of magnetofossils at the paleocene eocene boundary from synchrotron based transmission x ray microscopy |
| url | http://hdl.handle.net/1721.1/102263 https://orcid.org/0000-0003-1676-3494 |
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