Analysis of the ferromagnetic contribution to the susceptibility by low field and high field methods in sedimentary rocks of the Southern Pyrenees and Northern Ebro foreland basin (Spain) |
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| Authors: | Óscar Pueyo Anchuela Antonio M Casas‐Sainz Emilio L Pueyo Andrés Pocoví Juan Andrés Gil Imaz |
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| Institution: | 1. Grupo de investigación Geotransfer, Departamento de Ciencias de la Tierra, Universidad de Zaragoza, , CP. 50.009 Zaragoza, Spain;2. Instituto Geológico y Minero de Espa?a, Unidad de Zaragoza, , B. 50006 Zaragoza, Spain |
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| Abstract: | Magnetic susceptibility in rocks is the sum of the contributions of different magnetic particles (paramagnetic, diamagnetic and ferromagnetic s.l.). These contributions can be measured at variable temperatures or at variable fields (hysteresis loops). Both are time‐consuming techniques that cannot be routinely used in magnetic fabrics analysis. In this study, we propose a simplified method to determine the ferro‐ and paramagnetic contributions to the susceptibility, based on the discrete measurement of susceptibility at two different fields (near 0 and 2.5 T). The results obtained in samples from the Southern Pyrenees and Ebro Basin indicate that the ferromagnetic contribution vary considerably within homogeneous susceptibility values and within the expected range of paramagnetic values. Standard bulk susceptibilities higher than 200 10?6 SI contribute significantly to the ferromagnetic fraction (>50% on average). |
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