Relative geomagnetic paleointensity from the Jaramillo Subchron to the Matuyama/Brunhes boundary as recorded in a Mediterranean piston core Jaume Dinare ©s-Turell a; *, Leonardo Sagnotti a , Andrew P. Roberts b a Istituto Nazionale di Geo¢sica e Vulcanologia, Via di Vigna Murata 605, 00143 Rome, Italy b School of Ocean and Earth Science, University of Southampton, Southampton Oceanography Centre, European Way, Southampton SO14 3ZH, UK Received 12 July 2001; received in revised form 18 October 2001; accepted 18 October 2001 Abstract Piston core LC07, located west of the Sicily Strait in the Mediterranean Sea, unambiguously records the Matuyama/ Brunhes (M/B) and the upper Jaramillo polarity reversals, with similar average sediment accumulation rates (SARs) for the Brunhes Chron (2.29 cm/kyr) and late Matuyama Chron C1r.1r (2.19 cm/kyr). We report a relative paleointensity record for the interval spanning the M/B boundary down into the Jaramillo Subchron, which is unique in the Mediterranean because existing records from this basin cover only the last 80 kyr. The average SAR in core LC07 is used to translate the depth-related paleointensity record to the time domain; the ratio of anhysteretic remanent magnetization to low-field magnetic susceptibility is climatically sensitive and is used to tune the age model. This correlation produces a good fit to the global ice volume model derived for summer insolation at 65³N. With this age model, a paleointensity minimum in association with the M/B boundary has a duration of about 4^5 kyr, while the directional change has a duration of 6 3 kyr. A second paleointensity minimum of similar duration is found about 16 kyr below the M/B boundary. This feature (precursor or `dip' in the literature) has previously been recognized at the same time interval in many marine records, which reinforces the validity of our age model. Other relative paleointensity minima are found within chron C1r.1r, and, within the uncertainties of the respective age models, these minima coincide with those observed from the few published coeval paleointensity records. In particular, there is good correspondence between the ages of minima at about 0.92 and 0.89 Ma, which probably correlate with two geomagnetic excursions (Santa Rosa and Kamikatsura, respectively) that have been recorded in lava flows and dated using the 40 Ar/ 39 Ar technique. In contrast, a recently dated excursion at 0.83 Ma from La Palma seems to correspond to a paleointensity maximum. This observation is opposite to that expected and this excursion needs to be confirmed. In contrast to some recently published paleointensity records, spectral analysis of the LC07 record does not reveal identification of significant power at the orbital obliquity frequency. ß 2002 Elsevier Science B.V. All rights reserved. Keywords: paleointensity; magnetic ¢eld; Matuyama Chron; Jaramillo Subchron; Brunhes Chron; Mediterranean Sea 1. Introduction The possibility of retrieving relative intensity variations of the Earth's magnetic ¢eld from sedi- 0012-821X / 02 / $ ^ see front matter ß 2002 Elsevier Science B.V. All rights reserved. PII:S0012-821X(01)00563-5 * Corresponding author. Fax: +39-6-5186 0397. E-mail address: dinares@ingv.it (J. Dinare ©s-Turell). Earth and Planetary Science Letters 194 (2002) 327^341 www.elsevier.com/locate/epsl