Tectonic history of northern New Caledonia Basin from deep offshore seismic reflection: Relation to late Eocene obduction in New Caledonia, southwest Pacific Auteur(s) : Collot, Julien Geli, Louis Lafoy, Y Vially, R Cluzel, D Klingelhoefer, Frauke Nouze, Herve Éditeur(s) : AGU Résumé : New, high-quality multichannel seismic reflection data from the western New Caledonia offshore domain allow for the first time the direct, continuous connection of seismic reflectors between the Deep Sea Drilling Project 208 drill hole on the Lord Howe Rise and the New Caledonia Basin. A novel seismic interpretation is hence proposed for the northern New Caledonia Basin stratigraphy, which places the Eocene/Oligocene unconformity deeper than previously thought and revisits the actual thickness of the pre-Oligocene sequences. A causal link is proposed between the obduction of the South Loyalty Basin over New Caledonia (NC) and the tectonic history of the northern New Caledonia Basin. Here it is suggested that as the South Loyalty Basin was being obducted during early Oligocene times, the NC Basin subsided under the effect of the overloading and underthrusted to accommodate the compressional deformation, which resulted in (1) the uplift of the northern Fairway Ridge and (2) the sinking of the western flank of New Caledonia. This event also had repercussions farther west with the incipient subsidence of the Lord Howe Rise. Tectonics (0278-7407) (AGU), 2008-12 , Vol. 27 , N. TC6006 , P. 1-20 Droits : 2008 American Geophysical Union http://archimer.ifremer.fr/doc/2008/publication-4782.pdf DOI:10.1029/2008TC002263 http://archimer.ifremer.fr/doc/00000/4782/ | Partager |
Mesozoic history of the Fairway-Aotea Basin: Implications for the early stages of Gondwana fragmentation Auteur(s) : Collot, Julien Herzer, R. Lafoy, Y. Geli, Louis Éditeur(s) : American Geophysical Union Résumé : The Fairway Ridge is a buried continental structure that separates the Fairway Basin from the New Caledonia Basin. The proposed Cretaceous age of the Fairway Basin has remained highly hypothetical to date. Deep offshore petroleum exploration wells revealed well-dated Mesozoic carbonaceous sedimentary rocks in the Taranaki Basin at the southern end of the Aotea Basin. In this paper we use geophysical data to confirm the continuity of the 2000 km long Fairway-Aotea Basin connecting New Caledonia to New Zealand and prove its early Late Cretaceous age. Analysis of seismic reflection profiles together with newly compiled gravity and magnetic maps reveals Late Cretaceous NESW trending lineaments projecting northeastward from major Tasman Sea fracture zones and the Bellona Trough, which demonstrate that the opening of the Fairway-Aotea Basin predates the opening of the Tasman Sea. This result combined with observations of the Mesozoic regional geology suggests that the Lord Howe, Fairway, and Norfolk ridges are part of a remnant late Early Cretaceous continental arc, which was fragmented into three pieces by the late Early to early Late Cretaceous. This event might be contemporaneous with a plate motion change between the Gondwana and Pacific plates and/or the arrival of the Hikurangi plateau in the subduction zone around 105 Ma, which caused the cessation of subduction along this plate boundary. We interpret either of those two events as being possible trigger events for the postEarly Cretaceous fragmentation of the eastern Gondwana margin in a slab retreat process. Geochemistry Geophysics Geosystems - G3 (1525-2027) (American Geophysical Union), 2009-12 , Vol. 10 , N. 12 , P. 1-24 Droits : 2009 American Geophysical Union http://archimer.ifremer.fr/doc/2009/publication-7322.pdf DOI:10.1029/2009GC002612 http://archimer.ifremer.fr/doc/00000/7322/ | Partager |
Crustal structure of the basin and ridge system west of New Caledonia (southwest Pacific) from wide-angle and reflection seismic data. Auteur(s) : Klingelhoefer, Frauke Lafoy, Y Collot, Julien Cosquer, Emmanuel Geli, Louis Nouze, Herve Vially, R Éditeur(s) : American Geophysical Union Résumé : [1] During the Zoneco 11 marine geophysical survey (September 2004), two deep reflection seismic profiles recorded by ocean bottom seismometers were acquired in the offshore domain west of New Caledonia. The northern profile crosses the New Caledonia Basin, the Fairway Ridge, the Fairway Basin, and the Lord Howe Rise. The southern profile crosses the Norfolk Rise south of New Caledonia, the New Caledonia Basin, the Fairway Ridge and Basin, and ends at the foot of Lord Howe Rise. On the northern profile the Lord Howe Rise has a crustal thickness of 23 km and exhibits seismic velocities and velocity gradients characteristic of continental crust. The crust thins to 12-15 km in the neighboring Fairway Basin, which is interpreted to be of thinned continental origin based on the seismic velocities. The crustal thickness of the Fairway Rise is 22 km, and it is also interpreted to be of continental origin. The New Caledonian Basin is underlain by crust of 10 km thickness, which shows unusally high velocities (between 7.0 and 7.4) uncharacteristic for either thinned continental or oceanic crust. On the southern profile the Norfolk Rise is also found to be of continental nature. Here, the New Caledonia Basin shows velocities, crustal thickness, and basement roughness characteristic of typical oceanic crust. The crust in the Fairway Basin shows higher velocities than on the northern profile, which could be caused by volcanic intrusions into the crust during extension. A deep reflector in the upper mantle was imaged underneath the New Caledonian Basin on the northern profile. Journal of Geophysical Research - Solid earth (0148-0227) (American Geophysical Union), 2007-11 , Vol. 112 , N. B11102 , P. NIL_71-NIL_88 Droits : 2007 American Geophysical Union http://archimer.ifremer.fr/doc/2007/publication-3543.pdf DOI:10.1029/2007JB005093 http://archimer.ifremer.fr/doc/00000/3543/ | Partager |