Multidecadally resolved polarity oscillations during a geomagnetic excursion

Abstract

Polarity reversals of the geomagnetic field have occurred through billions of years of Earth history and were first revealed in the early 20th century. Almost a century later, details of transitional field behavior during geomagnetic reversals and excursions remain poorly known. Here, we present a multidecadally resolved geomagnetic excursion record from a radioisotopically dated Chinese stalagmite at 107-91 thousand years before present with age precision of several decades. The duration of geomagnetic directional oscillations ranged from several centuries at 106-103 thousand years before present to millennia at 98-92 thousand years before present, with one abrupt reversal transition occurring in one to two centuries when the field was weakest. These features indicate prolonged geodynamo instability. Repeated asymmetrical interhemispheric polarity drifts associated with weak dipole fields likely originated in Earth's deep interior. If such rapid polarity changes occurred in future, they could severely affect satellites and human society.

Paleoamerican Occupation, Stone Tools from the Cueva del Medio, and Considerations for the Late Pleistocene Archaeology in Southern South America

“…kya short duration excursion cf. [152,155] might have had some kind of influence on the local archaeological process. In addition to this possible major cause of alterations, north of Ultima Esperanza in southern Chile, multidisciplinary research performed on sediments has suggested that a cosmic-impact generated biomass burning, climate change, and megafaunal extinctions at 12.8 cal.…”

One Hundred Thousand Years of Geomagnetic Field Evolution

“…Other archives for recording the paleomagnetic field include wind‐blown loess‐paleosol sediments, for example, sections from the Chinese Loess Plateau (Li et al, ; Pan et al, ; Zhu et al, ), and cave sediments and speleothems (e.g., Bourne et al, ; Lascu & Feinberg, ; Ponte et al, ; Ponte et al, ; Trindade et al, ; Zanella et al, ). The latter are cave formations that can provide high‐resolution records of geomagnetic excursions (Lascu et al, ; Lascu & Feinberg, ), for example, recently, Chou et al () presented a multidecadally resolved geomagnetic excursion (107–91 ka) in a Chinese stalagmite.…”

Fast Directional Changes during Geomagnetic Transitions: Global Reversals or Local Fluctuations?

“…These values are astonishing when we consider that the rate of change of the geomagnetic pole latitude during the last 10,000 years, as measured by the CALS10k.2 field model [11], has been at most 4 × 10 −2• per year. A number of independent studies [12,[12][13][14][15][16][17] have also reported more recent directional paleomagnetic variations of the order of 10 degrees per year, primarily during geomagnetic reversals and excursions (see Figure 1). (a) Summary of rapid paleomagnetic variations from selected, published datasets (red symbols) and geomagnetic, spherical harmonics (SH) models (blue symbols).…”

“…Their location on the horizontal axis indicates the epoch at which the maximal variation was obtained (or reported). The sampling locations for the paleomagnetic datasets are reported in (b) and noted in both panels, and more information is available in relevant publications: Black Sea [18][19][20], Sanxing Cave [17], Sulmona Basin [13,14], Valle di Manche [16] and Sheep Creek [10]. The geomagnetic field models IMMAB4 [21], LSMOD.2 [22] and CALS10k.2 [11] have been sampled every 100 y for this calculation.…”