Magnetic Susceptibility Application: A Window onto Ancient Environments and Climatic Variations
Magnetic susceptibility (MS) is a tool frequently used by geologists on sediments or rocks to perform correlations and sea-level or climatic reconstructions. Applied measurements are made on unoriented, bulk samples and bulk MS is mostly influenced by the magnetic mineral content of the rock and often interpreted as influenced by detrital inputs. Magnetic data acquisition is fast and straightforward and this allows the high-resolution sampling needed for palaeoclimatic research (e.g. spectral analysis). However, the link with detrital inputs is not always preserved and the impact of diagenesis on the final MS signal can blur primary information. This volume includes contributions dealing with the origin of the magnetic minerals, and the application of MS as a palaeoenvironmental or palaeoclimatic proxy and also as a tool to provide astronomical calibration in order to improve the chronology of selected time intervals.
Magnetization carriers of grey to red deep-water limestones in the GSSP of the Givetian–Frasnian boundary (Puech de la Suque, France): signals influenced by moderate diagenetic overprinting
Published:January 01, 2015
Xavier Devleeschouwer, Laurent Riquier, Ondřej Bábek, David De Vleeshouwer, Estelle Petitclerc, Sarane Sterckx, Simo Spassov, 2015. "Magnetization carriers of grey to red deep-water limestones in the GSSP of the Givetian–Frasnian boundary (Puech de la Suque, France): signals influenced by moderate diagenetic overprinting", Magnetic Susceptibility Application: A Window onto Ancient Environments and Climatic Variations, A. C. Da Silva, M. T. Whalen, J. Hladil, L. Chadimova, D. Chen, S. Spassov, F. Boulvain, X. Devleeschouwer
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Limestones at the Puech de la Suque Global Boundary Stratotype Section and Point (GSSP) of the Givetian–Frasnian boundary show a drastic change towards much higher magnetic susceptibility values in the Givetian rocks. Different rock magnetic parameters indicate that ferromagnetic minerals are the main controlling factor. The ferromagnetic fraction is composed of low- (magnetite-type) and high-coercivity (hematite and goethite) phases. Confirmed by the spectral reflectance, high coercivity minerals are fluctuating along the section with a higher abundance in the basal Frasnian. These phases may be of secondary origin and produced during burial stage. The magnetite-type phase contains two different grain-size...