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| Detailed Reference Information |
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Flood, P.G. (2001). The 'Darwin point' of Pacific Ocean atolls and guyots; a reappraisal. Palaeogeography Palaeoclimatology Palaeoecology 175: 147-152. |
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The 'Darwin Point', where atolls drown, has been redefined as a function of climate, sea-level history, paleolatitude, seawater temperature and light. During the last 34 Ma, in the Hawaiian-Emperor Chain, the Darwin Point has been shown to shift at least between 24 and 30 degrees N latitude. Atoll drowning there is correlated with decreased seawater temperature and light and depends on sea-level history as well as the elevation of atoll summits at the time of sea-level transgressions. If the atoll top falls below 30 m with respect to sea level and the rate of sea-level rise is more than 15 mm/yr, the atoll will drown. Results of the Ocean Drilling Program legs 143 and 144, which investigated the histories of several NW Pacific guyots, indicate that the demise of the shallow-water carbonate platforms there was related to either a temporal (110-100 Ma) eustatic sea-level event, the paleolatitude location (0-10 degrees S) of nutrient-rich water, and/or increased seawater temperature (greenhouse effect) unconducive to the production of calcium carbonate by shallow-water organisms. Hence, the Darwin Point phenomena of atolls and guyots cannot be viewed as a manifestation of any single factor, rather, it results from a combination of factors including: decreased water temperature and light related to higher latitude; the amplitude and rate of sea-level changes; presence of nutrient-rich waters; and/or elevated seawater temperatures. It is indeed dynamic, both in time, space, and cause. |
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Keywords
atolls, carbonate platforms, Cenozoic, Darwin point, East Pacific, Ocean Islands, Emperor Seamounts, Hawaii, hot spots, Leg 143, Leg 144, marine environment, North Pacific, Northwest Pacific, Ocean Drilling, Program, ocean floors, Oceania, Pacific Ocean, Pacific Plate, paleo-oceanography, paleolatitude, plate tectonics, Polynesia, reefs, sea-level changes, seamounts, shallow-water environment, temperature, United States, West Pacific, 12 Stratigraphy, 07 Oceanography |
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Publisher
Elsevier Science
P.O. Box 211
1000 AE Amsterdam
The Netherlands
(+31) 20 485 3757
(+31) 20 485 3432
nlinfo-f@elsevier.com |
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