Capricorn Seamount: Difference between revisions
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A cap of [[limestone]]s lies on Capricorn Seamount;{{sfn|Crawford|Hildebrand|Dorman|Webb|2003|p=3}} its thickness is unknown.{{sfn|Lonsdale|1986|p=299}} [[Dredging]] has yielded [[pelagic ooze]] containing dark [[pumice]], dead [[coral]]s, [[faecal]] pellets, fossils of [[foraminifera]], [[gastropod]]s and [[pteropod]]s, [[limestone]]s with brown [[manganese dioxide]] encrustations, [[otolith]]s and sand.{{sfn|Kustanowich|1962|p=427}}{{sfn|Brodie|1965|p=151}} The foraminifera are of recent to [[Plio-Pleistocene]] age{{sfn|Kustanowich|1962|p=433}} and the limestones formed in shallow water.{{sfn|Lonsdale|1986|p=313}} |
A cap of [[limestone]]s lies on Capricorn Seamount;{{sfn|Crawford|Hildebrand|Dorman|Webb|2003|p=3}} its thickness is unknown.{{sfn|Lonsdale|1986|p=299}} [[Dredging]] has yielded [[pelagic ooze]] containing dark [[pumice]], dead [[coral]]s, [[faecal]] pellets, fossils of [[foraminifera]], [[gastropod]]s and [[pteropod]]s, [[limestone]]s with brown [[manganese dioxide]] encrustations, [[otolith]]s and sand.{{sfn|Kustanowich|1962|p=427}}{{sfn|Brodie|1965|p=151}} The foraminifera are of recent to [[Plio-Pleistocene]] age{{sfn|Kustanowich|1962|p=433}} and the limestones formed in shallow water.{{sfn|Lonsdale|1986|p=313}} |
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== Fisheries == |
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[[Albacore]], [[bigeye]] and [[yellowfin]] aggregate at the seamount, and [[fishing]] catch rates are much higher than in the open ocean.<ref name="Morato2010" /> |
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== Origin, geologic history and present-day interaction with the Tonga Trench == |
== Origin, geologic history and present-day interaction with the Tonga Trench == |
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== References == |
== References == |
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{{Reflist|refs= |
{{Reflist|refs= |
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<ref name="Morato2010">{{cite journal |last1=Morato |first1=Telmo |last2=Hoyle |first2=Simon D. |last3=Allain |first3=Valerie |last4=Nicol |first4=Simon J. |title=Tuna Longline Fishing around West and Central Pacific Seamounts |journal=PLoS ONE |date=29 December 2010 |volume=5 |issue=12 |pages=4-5 |doi=10.1371/journal.pone.0014453 |url=https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3012065/ |issn=1932-6203}}</ref> |
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<ref name="Allain2008">{{cite journal |last1=Allain |first1=Valérie |last2=Kerandel |first2=Julie-Anne |last3=Andréfouët |first3=Serge |last4=Magron |first4=Franck |last5=Clark |first5=Malcolm |last6=Kirby |first6=David S. |last7=Muller-Karger |first7=Frank E. |title=Enhanced seamount location database for the western and central Pacific Ocean: Screening and cross-checking of 20 existing datasets |journal=Deep Sea Research Part I: Oceanographic Research Papers |date=1 August 2008 |volume=55 |issue=8 |page=1041 |doi=10.1016/j.dsr.2008.04.004 |url=https://www.sciencedirect.com/science/article/pii/S0967063708000824 |language=en |issn=0967-0637}}</ref> |
<ref name="Allain2008">{{cite journal |last1=Allain |first1=Valérie |last2=Kerandel |first2=Julie-Anne |last3=Andréfouët |first3=Serge |last4=Magron |first4=Franck |last5=Clark |first5=Malcolm |last6=Kirby |first6=David S. |last7=Muller-Karger |first7=Frank E. |title=Enhanced seamount location database for the western and central Pacific Ocean: Screening and cross-checking of 20 existing datasets |journal=Deep Sea Research Part I: Oceanographic Research Papers |date=1 August 2008 |volume=55 |issue=8 |page=1041 |doi=10.1016/j.dsr.2008.04.004 |url=https://www.sciencedirect.com/science/article/pii/S0967063708000824 |language=en |issn=0967-0637}}</ref> |
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<ref name="Arredondo2012">{{cite journal |last1=Arredondo |first1=Katrina M. |last2=Billen |first2=Magali I. |title=Rapid weakening of subducting plates from trench-parallel estimates of flexural rigidity |journal=Physics of the Earth and Planetary Interiors |date=1 April 2012 |volume=196-197 |page=3 |doi=10.1016/j.pepi.2012.02.007 |url=https://www.sciencedirect.com/science/article/pii/S0031920112000349 |language=en |issn=0031-9201}}</ref> |
<ref name="Arredondo2012">{{cite journal |last1=Arredondo |first1=Katrina M. |last2=Billen |first2=Magali I. |title=Rapid weakening of subducting plates from trench-parallel estimates of flexural rigidity |journal=Physics of the Earth and Planetary Interiors |date=1 April 2012 |volume=196-197 |page=3 |doi=10.1016/j.pepi.2012.02.007 |url=https://www.sciencedirect.com/science/article/pii/S0031920112000349 |language=en |issn=0031-9201}}</ref> |
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| Capricorn Seamount | |
|---|---|
 | |
| Summit depth | 360 metres (1,180 ft) |
| Location | |
| Coordinates | 18°37.20′S 172°10.64′W / 18.62000°S 172.17733°W[1] |
Capricorn Seamount is a seamount in Tonga.
Geography, research history and name
It lies 120 miles (190 km) east of Vavau Island in Tonga,[2] at 360 metres (1,180 ft) depth.[1] First examined by the RV Horizon during the Capricorn Expedition of the Scripps Institution of Oceanography, it was successfully dredged in 1958 by the RNZFA Tui during the Pacific Cruise of the New Zealand Oceanographic Institute.[3] It is also known as Capricorn guyot, Gora Kaprikorn and Capricorn tablemount.[4]
Geomorphology and geology
The large[5] guyot rises over 4 kilometres (2.5 mi)[6] from the eastern flank of the Tonga Trench[2] and has a 15 kilometres (9.3 mi) wide[6] flat top at 800–1,000 metres (2,600–3,300 ft) depth, which tilts gently westwards. A north-northeast trending scarp separates the flat top from another, shallower flat-topped knoll which also tilts westwards.[3] Additional volcanic cones dot the slopes of Capricorn Seamount.[7] The crust underneath the seamount is 75-95 million years old[8] and is thickened, perhaps by the seamount's lava flows.[9]
A cap of limestones lies on Capricorn Seamount;[6] its thickness is unknown.[10] Dredging has yielded pelagic ooze containing dark pumice, dead corals, faecal pellets, fossils of foraminifera, gastropods and pteropods, limestones with brown manganese dioxide encrustations, otoliths and sand.[2][3] The foraminifera are of recent to Plio-Pleistocene age[11] and the limestones formed in shallow water.[12]
Fisheries
Albacore, bigeye and yellowfin aggregate at the seamount, and fishing catch rates are much higher than in the open ocean.[13]
Origin, geologic history and present-day interaction with the Tonga Trench
Capricorn Seamount likely formed in the Miocene (23-5 million years ago[8]) as a volcano, perhaps part of a hotspot track which also includes Niue.[6] The volcano was later eroded until it received a flat summit surface, and eventually submerged.[14] It is unclear whether it ever featured coral reefs as no evidence of such growth has been found.[15]
The seamount is about to enter the Tonga Trench[16] and is breaking up in the process.[17] Capricorn Seamount is not the first seamount there to be subducted into the Tonga Trench, and previous subduction events may have deformed the trench.[18] A Mw 8.0 earthquake occurred in 1919 at the trench next to Capricorn Seamount,[19] and earthquakes occur underneath Capricorn Seamount where normal faults are apparent in the seafloor.[20]
References
- ^ a b "Capricorn Guyot". EarthRef.org.
- ^ a b c Kustanowich 1962, p. 427.
- ^ a b c Brodie 1965, p. 151.
- ^ Allain, Valérie; Kerandel, Julie-Anne; Andréfouët, Serge; Magron, Franck; Clark, Malcolm; Kirby, David S.; Muller-Karger, Frank E. (1 August 2008). "Enhanced seamount location database for the western and central Pacific Ocean: Screening and cross-checking of 20 existing datasets". Deep Sea Research Part I: Oceanographic Research Papers. 55 (8): 1041. doi:10.1016/j.dsr.2008.04.004. ISSN 0967-0637.
- ^ Lonsdale 1986, p. 296.
- ^ a b c d Crawford et al. 2003, p. 3.
- ^ Lonsdale 1986, p. 311.
- ^ a b Arredondo, Katrina M.; Billen, Magali I. (1 April 2012). "Rapid weakening of subducting plates from trench-parallel estimates of flexural rigidity". Physics of the Earth and Planetary Interiors. 196–197: 3. doi:10.1016/j.pepi.2012.02.007. ISSN 0031-9201.
- ^ Crawford et al. 2003, p. 6.
- ^ Lonsdale 1986, p. 299.
- ^ Kustanowich 1962, p. 433.
- ^ Lonsdale 1986, p. 313.
- ^ Morato, Telmo; Hoyle, Simon D.; Allain, Valerie; Nicol, Simon J. (29 December 2010). "Tuna Longline Fishing around West and Central Pacific Seamounts". PLoS ONE. 5 (12): 4–5. doi:10.1371/journal.pone.0014453. ISSN 1932-6203.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ Brodie 1965, p. 155.
- ^ Brodie 1965, p. 156.
- ^ Wright, Dawn J. (2000). "Bathymetry of the Tonga Trench and Forearc: a map series". Marine Geophysical Researches. 21 (5): 502. doi:10.1023/A:1026514914220.
- ^ Lonsdale 1986, p. 324.
- ^ Scholz & Small 1997, p. 489.
- ^ Scholz & Small 1997, p. 490.
- ^ White, R. B.; Wiens, D. A. (December 2002). "Outer Rise Seismicity and Dynamics: Implications for Plate Rheology and Seamount Loading at the Tonga Subduction Zone". AGUFM. 2002: T52B–1201.
Sources
- Brodie, JW (1965). "Capricorn Seamount, south-west Pacific Ocean" (PDF). Transactions of the Royal Society of New Zealand. 3 (10): 151–185.
{{cite journal}}: Invalid|ref=harv(help) - Crawford, Wayne C.; Hildebrand, John A.; Dorman, LeRoy M.; Webb, Spahr C.; Wiens, Douglas A. (2003). "Tonga Ridge and Lau Basin crustal structure from seismic refraction data". Journal of Geophysical Research: Solid Earth. 108 (B4). doi:10.1029/2001JB001435. ISSN 2156-2202.
{{cite journal}}: Invalid|ref=harv(help) - Kustanowich, S. (August 1962). "A Foraminiferal fauna from Capricorn Seamount, South-West equatorial Pacific". New Zealand Journal of Geology and Geophysics. 5 (3): 427–434. doi:10.1080/00288306.1962.10420098.
{{cite journal}}: Invalid|ref=harv(help) - Lonsdale, Peter (December 1986). "A multibeam reconnaissance of the Tonga Trench axis and its intersection with the Louisville guyot chain". Marine Geophysical Researches. 8 (4): 295–327. doi:10.1007/BF02084016.
{{cite journal}}: Invalid|ref=harv(help) - Scholz, Christopher H.; Small, Christopher (1 June 1997). "The effect of seamount subduction on seismic coupling". Geology. 25 (6): 487–490. doi:10.1130/0091-7613(1997)0252.3.CO;2. ISSN 0091-7613 – via ResearchGate.
{{cite journal}}: Invalid|ref=harv(help)