Osbourn Seamount
The Osbourn Seamount is a seamount in the south-west Pacific Ocean. It is the westernmost and oldest unsubducted seamount of the Louisville Ridge, with an estimated age of 78.8 ± 1.3 Ma.[1][2] Like other seamounts comprising the Louisville Ridge, it was formed by the Louisville hotspot which is currently located 4,300 km (2,700 mi) away near the Pacific-Antarctic Ridge.[3]
| Osbourn Seamount | |
|---|---|
  South Pacific Ocean | |
| Location | |
| Location | South Pacific Ocean |
| Coordinates | 26°S 175°W |
| Geology | |
| Type | Guyot |
| Volcanic arc/chain | Louisville Ridge |
| Age of rock | 76.7±0.8 Ma |
Osbourn Seamount will eventually be destroyed by subduction in the Tonga and Kermadec trenches once it is carried into the trenches by the ongoing plate motion.[4] The trench-chain collision zone is moving southward at a rate of 200 km (120 mi)/Ma because of the oblique angle between the trench and the Louisville chain. This further shortens the seamount's lifespan.[5] The flat top of the seamount is currently tilting down toward the trench because the seamount is sitting on the edge of the trench where the Australian Plate is being bent by subduction.[6]
A bathymetric high c. 2 km (1.2 mi) north-west of the Osbourn Seamount has been interpreted as the currently subducting portion of the Louisville chain, but this continuation is not aligned with the existent chain. The Osbourn Seamount is the same age as the Detroit Seamount (75.8±0.6 Ma), one of the oldest of the Hawaii–Emperor seamount chain, and a clockwise bend in the Louisville chain near Osbourn is similar to the Detroit-Meiji bend in the Hawaii–Emperor chain.[7]
References
- Notes
- Timm et al. 2013, Location of the Louisville seamount chain beneath the arc, pp. 5–6
- Koppers, Anthony A. P.; Gowen, Molly D.; Colwell, Lauren E.; Gee, Jeffrey S.; Lonsdale, Peter F.; Mahoney, John J.; Duncan, Robert A. (December 2011). "New 40Ar/39Ar age progression for the Louisville hot spot trail and implications for inter-hot spot motion". Geochemistry, Geophysics, Geosystems. 12 (12): n/a. Bibcode:2011GGG....12.AM02K. doi:10.1029/2011gc003804. ISSN 1525-2027.
- Hawkins, Lonsdale & Batiza 1987, Abstract
- Shukman, David (2011-12-06). "Subsea mountains' 'march to ruin'". BBC News. Retrieved 2018-06-15.
- Garcia-Castellanos, Torne & Fernandez 2000, 14:38
- Garcia-Castellanos, Torne & Fernandez 2000, 4:12
- Timm et al. 2013, Location of the Louisville seamount chain beneath the arc, pp. 5–6
- Sources
- Garcia-Castellanos, D.; Torne, M.; Fernandez, M. (2000). "Slab pull effects from a flexural analysis of the Tonga and Kermadec Trenches (Pacific Plate)" (PDF). Geophysical Journal International. 141 (2): 479–484. Bibcode:2000GeoJI.141..479G. doi:10.1046/j.1365-246x.2000.00096.x. Retrieved 9 April 2017.
- Hawkins, J. W.; Lonsdale, P. F.; Batiza, R. (1987). "Petrologic Evolution of the Louisville Seamount Chain". In Keating, B. H.; Fryer, P.; Batiza, R.; Boehlert, G. W. (eds.). Seamounts, islands, and atolls. Geophysical Monograph Series. Washington, D. C.: American Geophysical Union. pp. 235–254. Bibcode:1987GMS....43..235H. doi:10.1029/GM043p0235. ISBN 9781118664209.CS1 maint: ref=harv (link)
- Timm, C.; Bassett, D.; Graham, I. J.; Leybourne, M. I.; De Ronde, C. E.; Woodhead, J.; Layton-Matthews, D.; Watts, A. B. (2013). "Louisville seamount subduction and its implication on mantle flow beneath the central Tonga–Kermadec arc" (PDF). Nature Communications. 4: 1720. Bibcode:2013NatCo...4E1720T. doi:10.1038/ncomms2702. PMID 23591887. Retrieved 19 March 2017.CS1 maint: ref=harv (link)