| Title | Magnetic mineralogy of the Yaxcopoil-1 core, Chicxulub |
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| Author | Pilkington, M; Ames, D E ; Hildebrand, A R |
| Source | The Chicxulub Scientific Drilling Project; Meteoritics and Planetary Science vol. 39, no. 6, 2004 p. 831-841, https://doi.org/10.1111/j.1945-5100.2004.tb00933.x  Open Access |
| Links | Abstract - Résumé
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| Links | The Chicxulub Scientific Drilling Project
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| Image |  |
| Year | 2004 |
| Alt Series | Geological Survey of Canada, Contribution Series 2003222 |
| Publisher | Wiley-Blackwell |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Area | Chicxulub; Mexico |
| Lat/Long WENS | -90.5000 -88.5000 22.0000 20.2500 |
| Subjects | extraterrestrial geology; geochemistry; geophysics; metallic minerals; mineralogy; magnetic properties; magnetic susceptibility; magnetite; remanent magnetism; magnetic anomalies; magnetic surveys;
magnetic surveys, airborne; magnetism; alteration; mafic rocks; amphibole; pyroxene |
| Illustrations | magnetic profiles; magnetic cross-sections; tables; photomicrographs |
| Abstract | Core from the Yaxcopoil-1 (Yax-1) hole, drilled as a result of the Chicxulub Scientific Drilling Project (CSDP), has been analyzed to investigate the relationship between opaque mineralogy and rock
magnetic properties. Twenty one samples of suevite recovered from the depth range 818-894 m are generally paramagnetic, with an average susceptibility of 2000 × 10-6 SI and have weak remanent agnetization intensities (average 0.1 A/m). The
predominant magnetic phase is secondary magnetite formed as a result of low temperature (<150 °C) alteration. It occurs in a variety of forms, including vesicle infillings associated with quartz and clay minerals and fine aggregates between
plagioclase/diopside laths in the melt. Exceptional magnetic properties are found in a basement clast (metamorphosed quartz gabbro), which has a susceptibility of >45000 × 10-6 SI and a remanent magnetization of 77.5 A/m. Magnetic mafic basement
clasts are a common component in the Yax-1 impactite sequence. The high susceptibility and remanence in the mafic basement clasts are caused by the replacement of amphiboles and pyroxenes by an assemblage with fine <1 um magnetite,
ilmenite,
K-feldspar, and stilpnomelane. Replacement of the mafic minerals by the magnetic alteration assemblage occurred before impact. Similar alteration mechanisms, if operative within the melt sheet, could explain the presence of the high amplitude
magnetic anomalies observed at Chicxulub. |
| GEOSCAN ID | 214971 |
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