@article{fdi:010068153,
  title = {{W}hen and why sediments fail to record the geomagnetic field during polarity reversals},
  author = {{V}alet, {J}. {P}. and {M}eynadier, {L}. and {S}imon, {Q}. and {T}houveny, {N}icolas},
  editor = {},
  language = {{ENG}},
  abstract = {{W}e present four new records of the {M}atuyama-{B}runhes ({M}-{B}) reversal from sediments of the {E}quatorial {I}ndian {O}cean, {W}est {E}quatorial {P}acific and {N}orth {A}tlantic {O}ceans with deposition rates between 2 cm/kyr and 4.5 cm/kyr. {T}he magnetic measurements were performed using 8 cc cubic samples and provided well-defined reverse and normal polarity directions prior and after the last reversal. {I}n three records stepwise demagnetization of the transitional samples revealed a succession of scattered directions instead of a well-defined characteristic component of magnetization. {T}here is no relationship with changes in magnetic mineralogy, magnetic concentration and magnetic grain sizes. {T}his behavior could be caused by weakly magnetized sediment. {H}owever the transitional samples of two cores have almost three orders of magnitude stronger magnetizations than the non-transitional samples that yielded unambiguous primary directions in the other two cores. {M}oreover a similar proportion of magnetic grains was aligned in all records. {T}herefore, the large amount of magnetic grains oriented by the weak transitional field did not contribute to improve the definition of the characteristic component. {W}e infer that the weakness of the field might not be only responsible. {A}ssuming that the transitional period is dominated by a multipolar field, it is likely that the rapidly moving non-dipole components generated different directions that were recorded over the 2 cm stratigraphic thickness of each sample. {T}hese components are carried by grains with similar magnetic properties yielding scattered directions during demagnetization. {I}n contrast, the strongly magnetized sediments of the fourth core from the {W}est {E}quatorial {P}acific {O}cean were exempt of problems during demagnetization. {T}he declinations rotate smoothly between the two polarities while the inclinations remain close to zero. {T}his scenario results from post-depositional realignment that integrated various amounts of pre- and post-transitional magnetic directions within each sample. {T}he present results point out the impossibility of extracting reliable information on geomagnetic reversals from low-medium deposition rate sediments with the current sampling techniques. {A}mong other features, they put in question the relationship between reversal duration and site latitude.},
  keywords = {geomagnetic reversals ; magnetization acquisition ; rock magnetism ; sediment ; demagnetization ; {OCEAN} {INDIEN} ; {PACIFIQUE} ; {ZONE} {EQUATORIALE} ; {ATLANTIQUE} {NORD}},
  booktitle = {},
  journal = {{E}arth and {P}lanetary {S}cience {L}etters},
  volume = {453},
  numero = {},
  pages = {96--107},
  ISSN = {0012-821{X}},
  year = {2016},
  DOI = {10.1016/j.epsl.2016.07.055},
  URL = {https://www.documentation.ird.fr/hor/fdi:010068153},
}