Kermadec Trench
TheKermadec Trenchis a linearocean trenchin the southPacific Ocean.It stretches about 1,000 km (620 mi) from theLouisville Seamount Chainin the north (26°S) to theHikurangi Plateauin the south (37°S), north-east ofNew Zealand'sNorth Island.[1]Together with theTonga Trenchto the north, it forms the 2,000 km (1,200 mi)-long, near-linearKermadec-Tonga subduction system,which began to evolve in theEocenewhen thePacific Platestarted to subduct beneath theAustralian Plate.Convergencerates along this subduction system are among the fastest on Earth, 80 mm (3.1 in)/yr in the north and 45 mm (1.8 in)/yr in the south.[2]
Geology
[edit]The Kermadec Trench is one of Earth's deepest oceanic trenches, reaching a depth of 10,047 metres (32,963 ft).[3]Formed by the subduction of thePacific Plateunder theIndo-Australian Plate,it runs parallel with and to the east of theKermadec Ridgeandisland arc.TheTonga Trenchmarks the continuation of subduction to the north.
The Kermadec Trench has a southern continuation in theturbidite-filledHikurangi Trough,but a series of seamounts on the Australian Plate act as a dam and prevents this turbidity from reaching the sediment-starved Kermadec Trench. Debris from a larger subducted seamount probably dammed the trench from 2 Ma to 0.5 Ma and similar events probably redirected sediments in similar ways before that.[4]
Two oceanic plates meet at the Kermadec Trench which is located far from any larger landmass. Because of this, the Pacific Plate as well as the trench itself is only covered byc.200 m (660 ft) of sediments. The trench is almost perfectly straight and its simple geometry is the result of the uniformity of the subducting sea-floor. This sea-floor formed at the extinctOsbourn Trough,located just north of theLouisville Seamount Chain.Abyssal hills on the subducting sea-floor are oriented perpendicular to the old spreading centre and the sea-floor is 72–80 Ma near the Louisville seamounts at the northern end and more than 100 Ma near Hikurangi Plateau at the southern end. There are no seamounts on the sea-floor near the Kermadec Trench except one sitting on the trench slope at31°30′S176°27′W/ 31.50°S 176.45°Wwhich has been dated to 54.8±1.9 Ma.[1]
The Hikurangi Plateau formed part of theOntong-Java-Manihiki-Hikurangilarge igneous province(LIP) during the Ontong Java Event 120Ma.The Manihiki Plateau is currently subducting under the southern part of the Kermadec Arc but most of it has already been subducted. The LIP-arc collision occurred 250 km (160 mi) north of its present location, but oblique plate convergence has migrated the subducted plateau southward.[5]
Fauna
[edit]In 2012, deep sea researchers discovered individuals of a species ofgiant amphipodat the trench's lowest depths.[6]Unlike mostamphipods,which are approximately 2.5 cm (1 inch) long, this species reaches up to 34 cm (13 inches) in length, and is milky-white.[6]
The second-deepest fish, thehadalsnailfishNotoliparis kermadecensis,is endemic to the trench and occupies a very limited depth range, 6,472 to 7,561 m (21,234 to 24,806 ft).[7]
A species ofpearlfish,Echiodon neotes,has been caught in the Kermadec Trench at a depth of 8,200–8,300 m (26,900–27,200 ft). All other known pearlfishes live in the range 1,800–2,000 m (5,900–6,600 ft) and the presence ofE. neotesat this depth remains unexplained.[8]
Exploration
[edit]In May 2014, theNereus,an unmanned research submarine operated by theWoods Hole Oceanographic Institution(WHOI), imploded due to high pressure at a depth of 9,990 metres while exploring the Kermadec Trench.[9]
In December 2022, a research team from theChinese Academy of SciencesandNational Institute of Water and Atmospheric Researchreached the bottom of the Scholl Deep nearly 10 km below the surface.[10]
See also
[edit]References
[edit]Notes
- ^abBillen & Gurnis 2005,p. 9
- ^Stratford et al. 2015,p. 4
- ^Linley, T.; Stewart, AL; McMillan, PJ; Clark, MR; Gerringer, ME; Drazen, JC; Fujii, T; Jamieson, AJ (2017)."Bait attending fishes of the abyssal zone and hadal boundary: Community structure, functional groups and species distribution in the Kermadec, New Hebrides and Mariana trenches".Deep Sea Research Part I: Oceanographic Research Papers.121:38–53.Bibcode:2017DSRI..121...38L.doi:10.1016/j.dsr.2016.12.009.ISSN0967-0637.
- ^Lewis, Collot & Lallem 1998,Abstract
- ^Timm et al. 2014,Abstract; p. 2
- ^abMorelle, Rebecca(2 February 2012)."'Supergiant' crustacean found in deepest ocean ".BBC News.Retrieved13 May2014.
- ^Yancey et al. 2014,Significance; Fig. 1
- ^Fujii et al. 2010
- ^"Nereus, unmanned research sub, suffers 'catastrophic implosion' nearly 10 kilometres underwater".National Post.Toronto.Associated Press.12 May 2014.Retrieved13 May2014.
- ^Cowing, Keith (2022-12-04)."Chinese And New Zealand Scientists Dive to One of the Ocean's Deepest Regions".Astrobiology.Retrieved2022-12-31.
Bibliography
- Billen, M. I.; Gurnis, M. (2005)."Constraints on subducting plate strength within the Kermadec trench".Journal of Geophysical Research: Solid Earth.110(B5).Bibcode:2005JGRB..110.5407B.doi:10.1029/2004JB003308.
- Fujii, T.; Jamieson, A. J.; Solan, M.; Bagley, P. M.; Priede, I. G. (2010)."A large aggregation of liparids at 7703 meters and a reappraisal of the abundance and diversity of hadal fish".BioScience.60(7): 506–515.doi:10.1525/bio.2010.60.7.6.S2CID85118297.Retrieved29 April2017.
- Lewis, K. B.; Collot, J. Y.; Lallem, S. E. (1998)."The dammed Hikurangi Trough: a channel-fed trench blocked by subducting seamounts and their wake avalanches (New Zealand–France GeodyNZ Project)"(PDF).Basin Research.10(4): 441–468.Bibcode:1998BasR...10..441L.doi:10.1046/j.1365-2117.1998.00080.x.S2CID130811128.Retrieved29 April2017.
- Stratford, W.; Peirce, C.; Paulatto, M.; Funnell, M.; Watts, A. B.; Grevemeyer, I.; Bassett, D. (2015)."Seismic velocity structure and deformation due to the collision of the Louisville Ridge with the Tonga-Kermadec Trench"(PDF).Geophysical Journal International.200(3): 1503–1522.doi:10.1093/gji/ggu475.Retrieved16 April2017.
- Timm, C.; Davy, B.; Haase, K.; Hoernle, K. A.; Graham, I. J.; de Ronde, C. E.; Woodhead, J.; Bassett, D.; Hauff, F.; Mortimer, N.; Seebeck, H. C.; Wysoczanski, R. J.; Caratori-Tontini, F.; Gamble, J. A. (2014)."Subduction of the oceanic Hikurangi Plateau and its impact on the Kermadec arc"(PDF).Nature Communications.5:4923.Bibcode:2014NatCo...5.4923T.doi:10.1038/ncomms5923.PMID25230110.Retrieved9 April2017.
- Yancey, P. H.; Gerringer, M. E.; Drazen, J. C.; Rowden, A. A.; Jamieson, A. (2014)."Marine fish may be biochemically constrained from inhabiting the deepest ocean depths".PNAS.111(12): 4461–4465.Bibcode:2014PNAS..111.4461Y.doi:10.1073/pnas.1322003111.PMC3970477.PMID24591588.
External links
[edit]- "Kermadec Trench".Woods Hole Oceanographic Institution.Retrieved9 April2017.An animation of a 3D model of the Kermadec Trench