%0 Journal Article
%T Paleomagnetism of Ar-Ar dated lava flows from the Ceboruco-San Pedro volcanic field (western Mexico): Evidence for the Matuyama-Brunhes transition precursor and a fully reversed geomagnetic event in the Brunhes chron
%+ École normale supérieure - Paris (ENS-PSL)
%+ Institut de Physique du Globe de Paris (IPGP)
%A Petronille, Marie
%A Goguitchaichvili, Avto
%A Henry, Bernard
%A Alva-Valdivia, Luis M.
%A Rosas-Elguera, José
%A Urrutia-Fucugauchi, Jaime
%A Rodriguez Cejá, Maria
%A Calvo-Rathert, Manuel
%< avec comité de lecture
%@ 2169-9313
%J Journal of Geophysical Research : Solid Earth
%I American Geophysical Union
%V 110
%P pp. 655-675.
%8 2005
%D 2005
%Z 2005JGRB..110.8101P
%R 10.1029/2004JB003321
%Z Sciences of the Universe [physics]Journal articles
%X We report a detailed paleomagnetic and rock magnetic study of 17 independent lava flows belonging to the Trans-Mexican Volcanic Belt; 175 oriented samples were collected in the Ceboruco-San Pedro volcanic field. These sites were previously dated by means of a state-of-the-art 40Ar-39Ar geochronological method and span from 819 to 2 ka. Rock magnetic experiments, which included continuous susceptibility and hysteresis measurements, point to simple magnetic mineralogy. In most cases, the remanence is carried by Ti-poor titanomagnetite of pseudosingle-domain magnetic structure. Fourteen flows give normal magnetic polarities, while two are reversely magnetized; only one cooling unit yields intermediate paleodirections. The paleodirections of the flow dated at 819 ± 25 ka correspond to a VGP latitude of 18°N. This anomalous field behavior apparently recorded prior to the Matuyama-Brunhes (M-B) reversal may coincide with the transitionally magnetized lavas on La Palma, Canary Islands (40Ar-39Ar age of 822.2 ± 8.7 ka), and with an event featured in several marine sediment records. Thus this geomagnetic event, defined as M-B precursor, is probably global in extent. Two independent lava flows, dated at 623 ± 91 and 614 ± 16 ka, yield reverse paleodirections. Age uncertainties make it difficult to claim the discovery of a new geomagnetic event. It is possible that these lavas erupted during the worldwide observable Big Lost event (40Ar-39Ar age of 580.2 ± 7.8 ka), which has probably been longer and more complex than it is generally believed for geomagnetic excursions.
%G English
%2 https://insu.hal.science/insu-03601112/document
%2 https://insu.hal.science/insu-03601112/file/Journal%20of%20Geophysical%20Research%20Solid%20Earth%20-%202005%20-%20Petronille%20-%20Paleomagnetism%20of%20Ar%25u2010Ar%20dated%20lava%20flows%20from%20the.pdf
%L insu-03601112
%U https://insu.hal.science/insu-03601112
%~ INSU
%~ UNIV-PARIS7
%~ ENS-PARIS
%~ AFRIQ
%~ CNRS
%~ IPGP
%~ RIGL
%~ PSL
%~ SORBONNE-UNIVERSITE
%~ UNIV-PARIS
%~ ENS-PSL
%~ SU-TI
%~ ALLIANCE-SU