RT Journal Article
T1 The Blake geomagnetic excursion recorded in a radiometrically dated speleothem
A1 Osete López, María Luisa
A1 Martín Chivelet, Javier
A1 Rossi Nieto, Carlos
A1 Edwards, R. Lawrence
A1 Egli, Ramon
A1 Muñoz García, María Belén
A1 Wang, Xianfeng
A1 Pavón Carrasco, Francisco Javier
A1 Heller, Friedrich
AB One  of the most important developments in geomagnetism has been the recognition of polarity excursions of the Earth’s magnetic field. Accurate timing of the excursions is a key point for under standing the geodynamo process and for magnetostratigraphic correlation. One of the best-known  excursions is the Blake geomagnetic episode, which occurred during marine isotope stage MIS 5, but its morphology and age remain controversial. Here wes how, for the first time, the Blake excursion recorded in a stalagmite which was dated using the uranium-series dis equilibrium techniques. The characteristic remanent magnetisation is carried by fine-grained magnetite. The eventis documented by two reversed intervals (B1 and B2). The age of the eventis estimated to be between 116.5 ± 0.7 kyr BP and 112.0 ± 1.9 kyr BP, slightly younger (~3–4 kyr) than recent estimations from sedimentary records sated by astronomical tuning. Low values of relative palaeointensity during the Blake episode are  estimated, but a relative maximum in the palaeofield in tensity coeval with the complete reversal during  the B2 interval was observed. Duration of the Blake geomagnetic excursion is 4.5 kyr, two times lower than single excursions and slightly higher than the stimated diffusion time for the inner core (~3 kyr).
PB Elsevier Science B.V., Amsterdam
SN 0012-821X
YR 2012
FD 2012
LK https://hdl.handle.net/20.500.14352/43666
UL https://hdl.handle.net/20.500.14352/43666
LA eng
DS Docta Complutense
RD 20 abr 2025