This dataset includes both original and previously published paleomagnetic data.
The new data refer to a marine sediment sequence (ANTA02-AV43 core) collected in the in Wood Bay, located along the coast of Victoria Land, within the western Ross Sea (Antarctica) and spanning the last ca. 10 ka. The formerly published paleomagnetic data from coeval sediment cores refer to the from the RS15‐GC57 core of Truax et al. (2025) collected in the adjacent Robertson Bay, and from the PC18 and PC19 cores of Macrì et al. (2005), recovered from the continental rise of the Wilkes Land basin offshore the coast of East Antarctica. The data from these two latter cores were relocated to the location of the ANTA02-AV43 core with the Noel and Batt (1990) method.
The estimated age of the formerly published dataset has been re-evaluated after correlation of paleomagnetic trends with the ANTA02-AV43 core and prediction of geomagnetic variation at the ANTA02-AV43 site according to the CALS10k.2 model of Constable et al. (2016). We then combined the new ANTA02-AV43 dataset with existing Holocene records from sediment cores of comparable resolution (PC18 and PC19) to develop the paleomagnetic “HOLOANTA” stack. This composite record averages paleomagnetic data over the last 10,000 years in 200-year intervals. It includes relative paleointensity (RPI) as well as paleomagnetic inclination and declination data, providing a robust regional Holocene RPI curve alongside directional secular variation (PSV) trends.
Sediment cores PC02, PC03, and PC04 were recovered during the ship expedition MR16-09 Leg 2 of Japanese RV Mirai in 2017 (Murata et al., 2017) using piston corers. For paleo- and rock magnetic analyses clear plastic boxes with a volume of 7 cm3 were pressed into the split halves of the generally 1 m long sections of the sediment cores.
X-ray fluoresence (XRF) scans were performed with an Itrax XRF Corescanner (Cox Analytical systems) at Kochi Core Center, Japan (Hagemann et al. 2024). The downcore resolution was set to 5 mm, and the scans were performed with a Mo X-ray tube at 30 kV and 55 mA for a measurement time of 15 s. The Itrax X-ray beam was set to 0.2 mm × 20 mm. Measurements of low-field magnetic susceptibility (klf same as: k-bulk) and its anisotropy (AMS) were performed with an AGICO MFK1-A susceptibility meter. The principal AMS axes Kmax, Kint, and Kmin, the three axes of the anisotropy ellipsoid, were used to calculate the degree of anisotropy, as well as the shape factor of anisotropy.
The frequency dependency of magnetic susceptibility was determined with an automated MAGNON Variable Field Susceptibility Meter (VFSM) by measuring magnetic susceptibility at different frequencies with logarithmically equidistant steps at a field amplitude of 250 µT. Susceptibilities of core PC02 samples were measured at 7 frequencies F from 375 Hz to 4775 Hz. Samples from cores PC03 and PC04 were measured at 5 frequencies from 475 to 4775 Hz. The frequency dependency Dk/Dlog(F) then was determined by linear regression of susceptibility k versus the decadal logarithm of frequency F. Values are given as decay rate in percent over one frequency decade (% / decade (F)) relative to the measurement at the lowest frequency. Thus, values obtained are negative.
Measurements of the natural remanent magnetization (NRM) and of the anhysteretic remanent magnetization (ARM) were performed with a 2G 755 SRM long-core cryogenic magnetometer. ARMs were produced with a 2G660 single-axis alternating field (AF) demagnetizer using 100 mT alternating field and 50 µT static field. NRMs and ARMs both were stepwise demagnetized with the in-line 3-axes AF demagnetizer of the cryogenic magnetometer. AF steps for NRM: 0, 5, 10, 15, 20, 30, 40, 50, 65, 80, 100 mT. AF steps for ARM: 0, 10, 20, 30, 40, 50, 65, 80 mT. Iso-thermal remanent magnetizations (IRM) were imparted with a 2G 660 pulse magnetizer using 1500 mT for producing a saturation magnetization (SIRM) and -200 mT for remagnetization of the low-coercive fraction. Measurements were performed with a Molyneux spinner magnetometer.
Data records were turned into time series by applying the age model for PC03 (Hagemann et al., 2024), correlating PC02 to PC03, and correlating PC04 to PC03 (back to 140 ka) and further using the PISO1500 paleointensity stack (Channell et al., 2009), paleomagnetic data from the Black Sea (Liu et al., 2020, Nowaczyk et al., 2021), and paleoclimatic data from Antarctica (Jouzel et al., 2007; Bazin et al., 2013) for reference for older core sections.
Compilation of palaeomagnetic data from sediments and volcanic rocks from 68 sites spanning 30,000 to 50,000 years ago used to create the temporally continuous global spherical harmonic geomagnetic field model LSMOD.1. This is in supplement to the paper "Earth's magnetic field is (probably not reversing" (Brown et al. 2018)A description of how the data were treated is given in SI Appendix of the associated publication. A full list of complementary data sources (references) is given is provided with the data.-----------------For the volcanics there is one filevolc.txtThe headers are:Age[ka] - age in thousands of years before present (0 = 1950 AD).Error[ka] - uncertainty on the age.Lat[Deg] - Latitude of site in degrees.Lon[Deg] - Longitude of site in degrees.Dec[Deg] - Declination in degrees.Inc[Deg] - Inclination in degrees.Alpha95[Deg] - 95% circular confidence limit on the directional data.F[microT] - intensity in micro Tesla.F_Error[microT] - uncertainy on the intensity in micro Tesla.-9999 - no data-----------------For the sediments there are two types of files, those that end *.txt and those that end *int.txt.*.txt - directional data with the headers:Age[ka] - age in thousands of years before present (0 = 1950 AD).Lat[Deg] - Latitude of site in degrees.Lon[Deg] - Longitude of site in degrees.Dec[Deg] - Declination in degrees.Inc[Deg] - Inclination in degrees.-9999 - no data*int.txt - scaled intensity data using PADM2M (as described in Section S1.3 of SI Appendix)Age[ka] - age in thousands of years before present (0 = 1950 AD).Lat[Deg] - Latitude of site in degrees.Lon[Deg] - Longitude of site in degrees.F[microT] - Scaled intensity in micro Tesla.6 of the sediment data sets are individual records (BLS, CHI, MIN, PYR, SIO, S01).6 of the sediment data sets are stacks of records (BBS, NAS, NPS, OBS, SBS, SAS).All details of the records are given in Table S1 and Table S2 of the SI Appendix of the associated publication.