کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4741980 | 1641544 | 2011 | 9 صفحه PDF | دانلود رایگان |
Thermal demagnetization has been carried out on 20 mutually oriented chips to unravel the stable paleomagnetic record of LL6 St. Séverin. Whereas the higher unblocking fractions (520–560 °C) of natural remanent magnetization (NRM) are directionally scattered, the lower unblocking fractions (<520 °C) are relatively well constrained along a great circle in a stereographic projection. Microscopic analysis revealed St. Séverin to contain paramagnetic troilite and a ferromagnetic Fe–Ni system. A sharp unblocking around 560 °C during thermal demagnetization strongly indicates that tetrataenite is the sole NRM carrier in St. Séverin. The absence of kamacite contribution on NRM and the presence of a scattered higher unblocking fraction (520–560 °C) of NRM imply a sequence of brecciation and a shock-induced metamorphism rather than a thermal origin of NRM.
► Stable paleomagnetic directions were isolated from LL6 St. Séverin.
► Tetrataenite is responsible for the ancient remanent magnetization.
► St. Séverin records the evidence of brecciation and a subsequent metamorphism.
Journal: Physics of the Earth and Planetary Interiors - Volume 187, Issues 3–4, August 2011, Pages 292–300