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Maui Nui

Coordinates: 21°08′11″N 157°12′50″W / 21.1365°N 157.214°W / 21.1365; -157.214
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Bathymetry image of the Hawaiian archipelago - Oʻahu and Maui Nui in center
Synopsis of Maui Nui submergence history, showing extent of Maui Nui landmass at times indicated. "Ma" is abbreviation for mega-anna, millions of years ago. Light and dark shading shows extent of land during low and high sea stands of glacial cycles. Panel labelled "Recent" represents latest glacial cycle, and the low sea stand for that period occurred about 18,000 years ago.

Maui Nui is a modern geologists' name given to a prehistoric Hawaiian island and the corresponding modern biogeographic region. It corresponds to four modern islands: Maui, Molokaʻi, Lānaʻi, and Kahoʻolawe. Administratively, the four modern islands comprise Maui County (and a tiny part of Molokaʻi called Kalawao County). Long after the breakup of Maui Nui, the four islands of Maui Nui retained very similar plant and animal life. Thus, Maui Nui is not only a prehistoric island but also a modern biogeographic region.

Geology

Maui Nui formed and broke up during the Pleistocene Epoch, which lasted from about 2.58 million to 11,700 years ago.

Maui Nui is built from seven shield volcanoes. The three oldest are Penguin Bank, West Molokaʻi, and East Molokaʻi, which probably range from slightly over to slightly less than 2 million years old. The four younger volcanoes are Lāna‘i, West Maui, Kaho‘olawe, and Haleakalā, which probably formed between 1.5 and 2 million years ago.[1]

At its prime 1.2 million years ago, Maui Nui was 14,600 square kilometres (5,600 sq mi), 50% larger than today's Hawaiʻi Island. The island of Maui Nui included the four modern islands (Maui, Molokaʻi, Lānaʻi, and Kahoʻolawe) and landmass east of Molokaʻi called Penguin Bank, which is now completed submerged.[2]

Maui Nui broke up as rising sea levels flooded the connections between the volcanoes. The breakup was complex because global sea levels rose and fell intermittently during the Quaternary glaciation. About 600,000 years ago, the connection between Molokaʻi and the island of Lāna‘i/Maui/Kahoʻolawe became intermittent. About 400,000 years ago, the connection between Lāna‘i and Maui/Kahoʻolawe also became intermittent. The connection between Maui and Kahoʻolawe was permanently broken between 200,000 and 150,000 years ago. Maui, Lāna‘i, and Molokaʻi were connected intermittently thereafter, most recently about 18,000 years ago during the Last Glacial Period.[2]

Today, the sea floor between these four islands is relatively shallow, about 500 metres (1,600 ft) deep. At the outer edges of former Maui Nui, as with the edges of all Hawaiian Islands, the sea floor plummets to the abyssal plain of the Pacific Ocean.[1]

See also

References

  1. ^ a b "Volcano Watch — A geologic tour of the Hawaiian Islands: Maui | U.S. Geological Survey". www.usgs.gov. Retrieved 2023-04-17.
  2. ^ a b "Volcano Watch — Once a big island, Maui County now four small islands | U.S. Geological Survey". www.usgs.gov. Retrieved 2023-04-17.

21°08′11″N 157°12′50″W / 21.1365°N 157.214°W / 21.1365; -157.214

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