Aden-Owen-Carlsberg Triple Junction
The Aden-Owen-Carlsberg Triple Junction (AOC), also known as the Arabia–India–Somalia Triple Junction, is a triple junction that connects the Aden Ridge, Owen Fracture Zone, and Carlsberg Ridge in the northwest Indian Ocean. It has been described as one of only three RRF (ridge-ridge-fault) triple junctions on Earth, besides the Azores Triple Junction and Chile Triple Junction. However, because the fault arm of such unstable triple junctions tend to evolve into a spreading centre, all three cases have quickly evolved into stable RRR triple junctions.[1]
Since a reorganisation of the involved tectonic plates c. 10 Ma the AOC moves in discrete steps westward along the Aden Ridge. West of the southern termination of the Owen fracture Zone, the Beautemps-Beaupré Basin, a new plate boundary develops and the basin will be transferred from the Arabian Plate to the Indian Plate in a near future.[2]
The Carlsberg Ridge was opened between the Seychelles and India in the Early Tertiary and has since undergone three stages of spreading. A first, fast stage 61 to 51 Ma with a 6 cm/year (2.4 in/year) half-rate spreading; a second 39 to 23 Ma ultra-slow (0.6 cm/year (0.24 in/year)) stage during the India-Eurasia collision; followed by the present slow (1.2 cm/year (0.47 in/year)) spreading which reaches 2.2 ± 0.1 cm/year (0.866 ± 0.039 in/year) in its northern end. This latest stage was initiated by the opening of the Gulf of Aden during which the Aden Ridge began to quickly propagate westward at a rate of 200 km (120 mi)/Ma.[3]
The Owen Fracture Zone, together with the Dalrymple Trough in its northern end, is a
The relative motion between the
References
Notes
- ^ Fournier et al. 2008, Fig. 1, p. 576; Conclusions, pp. 586–587
- ^ Fournier et al. 2010, Fig. 7, p. 10
- ^ a b Fournier et al. 2008, Geodynamic setting of the AOC triple junction, pp. 576–578
- ^ Iaffaldano, Hawkins & Sambridge 2014, Abstract
Sources
- Fournier, M.; Chamot-Rooke, N.; Petit, C.; Huchon, P.; Al-Kathiri, A.; Audin, L.; Beslier, M.-O.; d'Acremont, E.; Fabbri, O.; Fleury, J.-M.; Khanbari, K.; Lepvrier, C.; Leroy, S.; Maillot, B.; Merkouriev, S. (2010). "Arabia-Somalia plate kinematics, evolution of the Aden-Owen-Carlsberg triple junction, and opening of the Gulf of Aden" (PDF). Journal of Geophysical Research: Solid Earth. 115 (B4). .
- Fournier, M.; Petit, C.; Chamot-Rooke, N.; Fabbri, O.; Huchon, P.; Maillot, B.; Lepvrier, C. (2008). "Do ridge–ridge–fault triple junctions exist on Earth? Evidence from the Aden–Owen–Carlsberg junction in the NW Indian Ocean". Basin Research. 20 (4): 575–590. .
- Iaffaldano, G.; Hawkins, R.; Sambridge, M. (2014). "Bayesian noise-reduction in Arabia/Somalia and Nubia/Arabia finite rotations since ~20 Ma: Implications for Nubia/Somalia relative motion". Geochemistry, Geophysics, Geosystems. 15 (4): 845–854. hdl:1885/70787.