Continental shelves/South east Asian

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Map of Lesser Sunda Islands includes Bali, Lombok, Sumbawa, Flores, Lembata, Pantar, Sumba, Savu, Rote Island and Timor, also Wetar, the Kangean Islands, the Tengah Islands, the Sabalana Islands and the Selayar Islands. Credit: Lencer.{{free media}}

"The earliest evidence for seafaring thus far occurs on Flores, the largest island in the island chain known as Lesser Sunda, located in eastern Indonesia, currently some 500 km from Java, the world's most populous island. Stone tools were found in association with faunal remains and date to at least 800,000 years ago implying that Homo erectus might have been the world's first seafarers [...]."[1]

According to the map above, Flores is on a thin continental shelf extending from Java.

Australia-New Zealand shelves[edit | edit source]

Map shows the location of oceanic plateaus (in green) in the Australia-New Zealand region of the South Pacific. Credit: PeterTHarris.{{free media}}

The Manihiki Plateau, an oceanic plateau in the south-west Pacific Ocean, was formed by volcanic activity 125 to 120 million years ago during the mid-Cretaceous period at a triple junction] plate boundary called the Tongareva triple junction.[2] 125 million years ago the Manihiki Plateau formed part of the giant Ontong Java-Manihiki-Hikurangi plateau.[3]

The Manihiki Plateau extends from 3°S to 6°S and 159°W to 169°W covering 770,000 km2 (300,000 sq mi), has an estimated volume of 8,800,000 km3 (2,100,000 cu mi) with a crustal thickness of 15–25 km (9.3–15.5 mi) and contains several of the Cook Islands are located on the southern part: Pukapuka (Danger), Nassau], Suvorov], Rakahanga, and Manihiki, with the Tokelau Basin to the west, the Samoan Basin to the south, the Penrhyn Basin to the east, and the Central Pacific Basin to the north.[4]

It reaches up to 2.5–3 km (1.6–1.9 mi) below sea level, several kilometres shallower than the surrounding basins, can be divided into three regions: the south-eastern High Plateau is the shallowest and flattest; its basement is covered by up to a kilometre of pelagic sedimentary rock, the Western Plateaus, north-west of the High Plateau, a series of ridges and seamounts, the North Plateau is small and almost separated from the rest of the Manihiki Plateau.[5]

The High Plateau is the largest part of Manihiki covering 400,000 km2 (150,000 sq mi) above 4000 m; the second largest part is the Western Plateaus covering 250,000 km2 (97,000 sq mi) above 5000 m and reaching 3,500–4,000 m (11,500–13,100 ft) below sea level, and the smallest part, the North Plateau, covers 60,000 km2 (23,000 sq mi) above 4500 m and reaches 1,500 m (4,900 ft), where these plateaus are separated by failed rifts.[4]

See also[edit | edit source]

References[edit | edit source]

  1. Katelyn DiBenedetto and Alan H Simmons (16 June 2016). Alan H Simmons. ed. A Brief History of Global Seafaring and Archaeology, In: Stone Age Sailors: Paleolithic Seafaring in the Mediterranean. London: Routledge. pp. 264. ISBN 1315419726. Retrieved 27 April 2019. 
  2. Larson, R. L.; Pockalny, R. A.; Viso, R. F.; Erba, E.; Abrams, L. J.; Luyendyk, B. P.; Stock, J. M.; Clayton, R. W. (2002). "Mid-Cretaceous tectonic evolution of the Tongareva triple junction in the southwestern Pacific Basin". Geology 30 (1): 67–70. doi:10.1130/0091-7613(2002)030<0067:MCTEOT>2.0.CO;2. Retrieved 11 December 2016. 
  3. Taylor, B. (2006). "The single largest oceanic plateau: Ontong Java–Manihiki–Hikurangi". Earth and Planetary Science Letters 241 (3): 372–380. doi:10.1016/j.epsl.2005.11.049. Retrieved 11 December 2016. 
  4. 4.0 4.1 Timm, C.; Hoernle, K.; Werner, R.; Hauff, F.; van den Bogaard, P.; Michael, P.; Coffin; Koppers, A. (2011). "Age and geochemistry of the oceanic Manihiki Plateau, SW Pacific: New evidence for a plume origin". Earth and Planetary Science Letters 304 (1): 135–146. doi:10.1016/j.epsl.2011.01.025. Retrieved 11 December 2016. 
  5. Ai, H. A.; Stock, J. M.; Clayton, R.; Luyendyk, B. (2008). "Vertical tectonics of the High Plateau region, Manihiki Plateau, Western Pacific, from seismic stratigraphy". Marine Geophysical Researches 29 (1): 13–26. doi:10.1007/s11001-008-9042-0. Retrieved 11 December 2016. 

External links[edit | edit source]