Moulin M. auteur aut IRD Fluteau F. auteur aut IRD Courtillot V. auteur aut IRD Marsh J. auteur aut IRD Delpech G. auteur aut IRD Quidelleur X. auteur aut IRD Gérard Martine auteur aut IRD Jay A. E. auteur aut IRD text journalArticle eng text/pdf born digital access We have carried out paleomagnetic sampling of a similar to 750 m sequence of the Karoo large igneous province (Naude's Nek Pass, South Africa). K-Ar dating (Cassignol-Gillot) has been performed on four samples from the 650 m upper unit (mean age 179.2 +/- 1.8 Ma) and a sample from the lower unit (184.8 +/- 2.6 Ma). A succession of two phases of volcanism is suggested. The lower 25 flows (115 m thick) have recorded a reversed polarity; the next 23 flows (135 m thick) are transitional and contribute a detailed record of the "Van Zijl" (1962) Jurassic reversal. The upper 38 flows (500 m thick) have normal polarity. Directional groups (DGs) of lava flows with quasi-identical remanence directions indicate eruption durations too short to have recorded geomagnetic secular variation and hence are interpreted as single eruptive events. Altogether, 19 DGs and 10 sheet lobes yield a sequence of 29 distinct directions. This could correspond to a total eruptive activity shorter than 3000 years, less than one per mil of the total duration over which the section was emplaced. We obtain a new paleomagnetic pole for South Africa at similar to 180 Ma (lambda = 75.2 degrees N, phi = 276.4 degrees E, A(95) = 5.8 degrees, N = 19), which is consistent with earlier reports. specialized 066 116 B07403 2011 0148-0227 https://www.documentation.ird.fr/hor/fdi:010053729 10.1029/2011jb008210 0148-0227 [F B010053729] https://www.documentation.ird.fr/hor/fdi:010053729 https://www.documentation.ird.fr/intranet/publi/2011/08/010053729.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2011-09-01 2023-02-13 fdi:010053729 fre