HAL will be down for maintenance from Friday, June 10 at 4pm through Monday, June 13 at 9am. More information
Skip to Main content Skip to Navigation
Journal articles

Palaeosecular variation in Java and Bawean Islands (Indonesia) during the Brunhes chron

Abstract : A palaeomagnetic study has been conducted from Indonesian lava flows and dykes. Sampling was concentrated to the Merapi and Merbabu volcanoes (central Java), the Bromo-Tengger volcanic complex, the Lurus volcano (both east of Java), and the Bawean Island. Numerical dating indicates that the rock units sampled have ages that are well distributed within the Brunhes chron. Only a few reverse polarity flows were probably emplaced during the late Matuyama chron. Alternating field (AF) and thermal demagnetization treatments were routinely used for all sites. Results from both methods were generally in good agreement, demonstrating the reliability and the reproducibility of the palaeomagnetic determinations obtained from 36 independent sites. The large dispersion of the directions and the age distribution indicate that a large spectrum of the secular variation has been sampled. Our best estimate of the mean Brunhes field direction in Java is characterized by a zero declination and an inclination anomaly of -4.7° (with a 95 per cent confidence angle of 5.3°). This value agrees with an axial dipolar field model, or a model to which a persisting zonal quadrupolar term of a few per cent of the geocentric axial dipole is added. This study adds new constraints to recent results which suggested that a large zone of negative inclination anomalies may have persisted in the southwestern Pacific ocean over the past 500 Kyr, and possibly extended toward the eastern Indian ocean. The present results do not support such an extension. They also suggest that the inclination anomaly may have varied over 100 Kyr, and that it was more pronounced in recent times.
Document type :
Journal articles
Complete list of metadata

Contributor : Nathalie Pothier Connect in order to contact the contributor
Submitted on : Monday, March 7, 2022 - 2:59:17 PM
Last modification on : Wednesday, March 9, 2022 - 3:36:00 AM


Publisher files allowed on an open archive


Distributed under a Creative Commons Attribution 4.0 International License



A. Elmaleh, J. -P. Valet, X. Quidelleur, A. Solihin, H. Bouquerel, et al.. Palaeosecular variation in Java and Bawean Islands (Indonesia) during the Brunhes chron. Geophysical Journal International, Oxford University Press (OUP), 2004, 157, pp.441-454. ⟨10.1111/j.1365-246X.2004.02197.x⟩. ⟨insu-03600287⟩



Record views


Files downloads