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  • 21 Aug, 2019

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Lord Howe Seamount Chain
The Lord Howe Seamount Chain formed during the Miocene. It features many coral-capped guyots and is one of the two parallel seamount chains alongside the east coast of Australia; the Lord Howe and Tasmantid seamount chains both run north-south through parts of the Coral Sea and Tasman Sea. These chains have longitudes of approximately 159°E and 156°E respectively.

Geography

The Lord Howe Seamount Chain has been known under a variety of different gazetted names, including the Lord Howe Seamounts, Lord Howe Guyots, Lord Howe Rise Guyots and the Middleton Chain.

Topographic map of Zealandia with the Lord Howe Rise to the north west of New Zealand labelled.

The Lord Howe Seamount Chain is on the western slope of Lord Howe Rise, a deep-sea elevated plateau which is a submerged part of Zealandia. The Tasmantid and Lord Howe seamount chains are both broadly within the Tasman basin (the abyssal plain between Lord Howe Rise and the Australian continental shelf), and lie on opposite sides of Dampier Ridge (a submerged continental fragment).

The Lord Howe Seamount Chain extends from north of the Chesterfield group of islands (17°S) to Flinders Seamount (34.7°S). It includes the officially named Nova Bank, Argo and Kelso seamounts, Capel and Gifford guyots, Middleton and Elizabeth reefs, Lord Howe Island and Ball's Pyramid.

Geology

The Lord Howe and Tasmantid chains each resulted from the Indo-Australian Plate moving northward over a stationary hotspot; historically the hotspot for the Lord Howe chain was expected to presently be beneath Flinders Seamount. but is now thought likely to be somewhat to the south of this, possibly beyond the Heemskerck and Zeehaen seamounts. Indeed the dating of this chain has only been as far south as Lord Howe Island which erupted 6.5 million years ago and there are other gaps in relevant knowledge of this hotspot chain. The chain has now been characterised by compositional analysis to be related at 28 million years to the South Rennell Trough spreading center as its potential initiation point with lessening magma being erupted progressively as the younger seamounts of the hot spot were formed. On the Australian mainland, a third north-south sequence of extinct volcanoes (which includes the Glass House Mountains) is likely to have the same origin. The Lord Howe Seamount Chain includes the following features:

Lord Howe Seamounts
Seamount Location Age Notes
Zeehaen Seamount 36°20′19″S 159°31′15″E / 36.33855°S 159.52079°E / -36.33855; 159.52079
Heemskerck Seamount 36°16′39″S 159°06′29″E / 36.27751°S 159.10809°E / -36.27751; 159.10809
Flinders Seamount 34°35′27″S 159°23′38″E / 34.59096°S 159.39376°E / -34.59096; 159.39376
Ball's Pyramid 31°21′15″S 159°15′06″E / 31.35417°S 159.25167°E / -31.35417; 159.25167
Lord Howe Island 31°33′15″S 159°05′06″E / 31.55417°S 159.08500°E / -31.55417; 159.08500 6.9 to 6.4 Ma
Elizabeth Reef 29°34′00″S 159°05′00″E / 29.56667°S 159.08333°E / -29.56667; 159.08333
Middleton Reef 29°27′00″S 159°07′00″E / 29.45°S 159.11667°E / -29.45; 159.11667
Gifford Guyot 26°40′00″S 159°25′00″E / 26.66667°S 159.41667°E / -26.66667; 159.41667 Dating of seamount top sediments is consistent with expected seamount age progression
Capel Bank 25°00′00″S 159°35′00″E / 25.0°S 159.58333°E / -25.0; 159.58333 Dating of seamount top sediments is consistent with expected seamount age progression
Kelso Bank 24°46′00″S 159°30′00″E / 24.76667°S 159.5°E / -24.76667; 159.5
Argo Bank 23°15′S 159°30′E / 23.25°S 159.5°E / -23.25; 159.5
Nova Bank 22°11′00″S 159°12′00″E / 22.18333°S 159.2°E / -22.18333; 159.2 23 Ma
Chesterfield Plateau 18°44′11″S 158°34′54″E / 18.736381°S 158.581567°E / -18.736381; 158.581567 28.1 ± 1.0 Ma
Horsehead Seamount 17°36′05″S 158°44′56″E / 17.601454°S 158.748849°E / -17.601454; 158.748849 27.24 ± 0.24 Ma
South Rennell Trough 28 Ma


See also

References

  1. ^ Seton, Maria; Williams, Simon; Mortimer, Nick; Meffre, Sebastien; Micklethwaite, Steven; Zahirovic, Sabin (2019). "Magma production along the Lord Howe Seamount Chain, northern Zealandia". Geological Magazine. 156 (9): 1605–1617. Bibcode:2019GeoM..156.1605S. doi:10.1017/S0016756818000912.
  2. ^ Willem J. M. van der Linden, Morphology of the Tasman sea floor. New Zealand Journal of Geology and Geophysics. Vol.13 (1970) 282-291.
  3. ^ Seton, Maria; Williams, Simon; Mortimer, Nick; Meffre, Sebastien; Micklethwaite, Steven; Zahirovic, Sabin (2019-01-22). "Magma production along the Lord Howe Seamount Chain, northern Zealandia". Geological Magazine. 156 (9): 1605–1617. Bibcode:2019GeoM..156.1605S. doi:10.1017/S0016756818000912. ISSN 0016-7568. S2CID 134379148.
  4. ^ "Marine Gazetteer Placedetails". Retrieved 2017-02-20.
  5. ^ McDougall et al, Dampier Ridge, Tasman Sea, as a stranded continental fragment. Australian Journal of Earth Sciences 41 (1994). 395-406.
  6. ^ Przeslawski et al. Biogeography of the Lord Howe Rise region, Tasman Sea. Deep-Sea Research Part II 58 (2011) 959–969.
  7. ^ W. J. Morgan and J. P. Morgan. Plate velocities in hotspot reference frame: electronic supplement
  8. ^ Hansma, Jeroen; Tohver, Eric (2020). "Southward Drift of Eastern Australian Hotspots in the Paleomagnetic Reference Frame Is Consistent With Global True Polar Wander Estimates". Frontiers in Earth Science. 8: 489. Bibcode:2020FrEaS...8..489H. doi:10.3389/feart.2020.544496.
  9. ^ Knesel, Kurt M.; Cohen, Benjamin E.; Vasconcelos, Paulo M.; Thiede, David S. (August 2008). "Rapid change in drift of the Australian plate records collision with Ontong Java plateau". Nature. 454 (7205): 754–757. Bibcode:2008Natur.454..754K. doi:10.1038/nature07138. ISSN 0028-0836. PMID 18685705. S2CID 4427792.
  10. ^ "GEBCO Undersea Feature Names Gazetteer".
  11. ^ Douglas (Smethurst), Amelia (2022). The East Australian, Tasmantid and Lord Howe volcanoes : exploring the origins of three, contemporaneous, parallel chains of volcanism. (PhD thesis and appendix) (Thesis). doi:10.7488/era/2805. Retrieved 2023-03-30.
  12. ^ McDougall, I; Embleton, B; Stone, D (1981). "Origin and evolution of Lord Howe Island, southwest Pacific Ocean". Journal of the Geological Society of Australia. 28 (1–2): 155–76. Bibcode:1981AuJES..28..155M. doi:10.1080/00167618108729154.
  13. ^ Quilty, Patrick G. (1993). "Tasmantid and Lord Howe seamounts: biostratigraphy and palaeoceanographic significance". Alcheringa: An Australasian Journal of Palaeontology. 17 (1): 27–53}. Bibcode:1993Alch...17...27Q. doi:10.1080/03115519308619487.
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