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Multidisciplinary Chronostratigraphy
Published in Wang Naiwen, J. Remane, Stratigraphy, 2020
It should, however, be stressed that the existence of a reliable OPTS based on oceanic anomalies is the decisive prerequisite for this kind of approach. Such a standard does not exist for the time before the Callovian/Oxfordian, which is the age of the oldest oceanic crust. The possibilities to use magnetostratigraphy in older rocks are thus much more limited. If a given event occurs in sediments of different polarity in different sections, all what this proves is that the respective levels cannot be of the same age. If a biostratigraphic zone corresoponds to three magnetic zones in one section and only to two in another one, the latter is without any doubt less complete. But, unlike the examples presented above, it is impossible to correlate magnetic zones from one section to another. Both sections may well be incomplete at different levels.
Nanomagnetism
Published in Chun Huh, Hugh Daigle, Valentina Prigiobbe, Maša Prodanović, Practical Nanotechnology for Petroleum Engineers, 2019
Chun Huh, Hugh Daigle, Valentina Prigiobbe, Maša Prodanović
Paleomagnetism is the study of the Earth’s magnetic field of rocks, sediment, or archaeological materials (Tauxe 2010). Magnetic minerals in rocks carry the information on the direction and intensity of the magnetic field when they form. This record provides information on the past behavior of Earth&s magnetic field and allows reconstruction of the past position of tectonic plates. The record of geomagnetic field reversals found in volcanic and sedimentary rock sequences (also known as magnetostratigraphy) provides a timescale and is used as a geochronology tool.
Diagenesis of magnetic minerals at the Southwest Pacific DSDP Site 277
Published in New Zealand Journal of Geology and Geophysics, 2020
The original aim of our work was to construct a magnetostratigraphic age model to establish more precise constraints for paleoecological and geochemical studies and to establish an environmental magnetic record of oceanographic changes. However, our expectation of success was low because these sediments were recovered by rotary drilling (the APC had not yet been developed) which often resulted in soft sediments being physically disturbed or stirred. Physical disturbance of sediments often (if not always) prevents construction of a magnetostratigraphy and correlation with the geomagnetic polarity timescale because NRM directions are destroyed. Nevertheless, inspection of core logs (Kennett and Houtz 1974) and photographs indicated patchy deformation and disturbance. Therefore it was decided to proceed with the study.