کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4679204 1634871 2009 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Self-reversal and apparent magnetic excursions in Arctic sediments
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات علوم زمین و سیاره ای (عمومی)
پیش نمایش صفحه اول مقاله
Self-reversal and apparent magnetic excursions in Arctic sediments
چکیده انگلیسی

The Arctic oceans have been fertile ground for the recording of apparent excursions of the geomagnetic field, implying that the high latitude field had unusual characteristics at least over the last 1–2 Myrs. Alternating field demagnetization of the natural remanent magnetization (NRM) of Core HLY0503-6JPC from the Mendeleev Ridge (Arctic Ocean) implies the presence of primary magnetizations with negative inclination apparently recording excursions in sediments deposited during the Brunhes Chron. Thermal demagnetization, on the other hand, indicates the presence of multiple (often anti-parallel) magnetization components with negative inclination components having blocking temperatures predominantly, but not entirely, below ~ 350 °C. Thermo-magnetic tests, X-ray diffraction (XRD) and scanning electron microscopy (SEM) indicate that the negative inclination components are carried by titanomaghemite, presumably formed by seafloor oxidation of titanomagnetite. The titanomaghemite apparently carries a chemical remanent magnetization (CRM) that is partially self-reversed relative to the detrital remanent magnetization (DRM) carried by the host titanomagnetite. The partial self-reversal could have been accomplished by ionic ordering during oxidation, thereby changing the balance of the magnetic moments in the ferrimagnetic sublattices.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Earth and Planetary Science Letters - Volume 284, Issues 1–2, 30 June 2009, Pages 124–131
نویسندگان
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