Könnecke L.K. auteur aut IRD Coffin M.F. auteur aut IRD Charvis Philippe auteur aut IRD text journalArticle eng text/pdf reformatted digital access We examine the early geological history of the southern Kerguelen Plateau (Indian Ocean) using ocean bottom seismometer ((ORS), multichannel seismic (MCS), and Ocean Drilling Program data. Velocity-depth models in the sedimentary Raggatt Basin are constrained by near-range OBS data (refractions and reflections, including multiples and converted shear waves) and migrated MCS data. The models elucidate the significance of Lower Cretaceous lava flows, Albian to Coniacian/Santonian terrestrial and terrigenous sediment, and Maastrichtian and Paleocene seismic sequences. The Albian/Aptian basaltic basement complex consists of an upper and a lower series. The upper series is characterized by average Vps of 4.6-4.7 km/s, an upward increase of intercalated terrestrial sediment and altered flowtops, and a concomitant decrease in flow thickness ; the lower series is marked by average Vps of 5.3-5.5 km/s, and contains thicker flows and less sediment. A volcanic center in the Raggatt Basin shows relatively low Vps (3.7-3.9 km/s for the upper series, 4.7-4.9 km/s for the lower series), and dipping reflections on the Raggatt Basin's flanks are also recorded as refractions. Terrestrial and terrigenous sediment of the Raggatt Basin, immediately overlying basement, is characterized by a seismic low-velocity layer with Vps ranging from 2.2-2.9 km/s and a thickness of greater than 1100 m in the central basin. Nearby source regions (e.g. Banzare Bank and other elevated areas south of the basin) account for a terrestrial and terrigenous sediment volume of approximately 12,500 km3, deposited over approximately 20 m.y. The depocenter of the Raggatt Basin began shifting in Santonian to early Maastrichtian time, and concluded by early late Paleocene time. (Résumé d'auteur) specialized PLATEAU BASSIN OCEANIQUE BASSIN SEDIMENTAIRE EROSION SUBSIDENCE STRATIGRAPHIE LITHOLOGIE ROCHE IGNEE PROFIL SISMIQUE FORAGE MODELISATION OCEAN INDIEN KERGUELEN 064GEOREG 103 B10 24,085-24,108 1998 0148-0227 https://www.documentation.ird.fr/hor/fdi:010024246 10.1029/98JB01495 0148-0227 [F B010024246] https://www.documentation.ird.fr/hor/fdi:010024246 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_textes_7/b_fdi_57-58/010024246.pdf IRD - Base Horizon / Pleins textes 2001-03-08 2021-05-20 fdi:010024246 fre