Sea level and coral atolls: Late holocene emergence in the Indian Ocean

Journal Article · Mon Jan 01 04:00:00 EST 1990 · Geology; (USA)

DOI:https://doi.org/10.1130/0091-7613(1990)018<0062:SLACAL>2.3.CO;2· OSTI ID:6140713

Woodroffe, C ^[1]; McLean, R ^[2]; Polach, H; Wallensky, E ^[3]

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1. Univ. of Wollongong, New South Wales (Australia)
2. Australian Defence Force Academy, Canberra (Australia)
3. Australian National Univ., Canberra (Australia)

The Cocos (keeling) Islands in the eastern Indian Ocean were visited by Charles Darwin, who described geomorphological evidence that he considered supported his subsidence theory of coral-reef development. However, several other accounts of the reef islands have questioned Darwin's interpretation, and have suggested that a conglomerate platform that underlies most of the reef islands may indicate recent emergence of the atoll. Radiocarbon ages on corals from this conglomerate platform, reported here, indicate that it formed in the late Holocene. Fossil in situ microatolls above present upper coral growth limits, the elevation of associated beachrock, and the morphological similarity of the conglomerate platform to the present reef-flat deposits indicate a late Holocene sea level above the present relative to the atoll. The atoll has undergone at least 0.5 m of emergence since about 3000 yr B.P. This represents the first radiometrically dated evidence of Holocene emergence from islands in the eastern or central Indian Ocean.

• OSTI ID: 6140713
• Journal Information: Geology; (USA), Journal Name: Geology; (USA) Vol. 18:1; ISSN GLGYB; ISSN 0091-7613
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
AGE ESTIMATION
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBON 14
CARBON ISOTOPES
CENOZOIC ERA
CNIDARIA
COELENTERATA
CONGLOMERATES
CORALS
EVEN-EVEN NUCLEI
GEOLOGIC AGES
GEOLOGIC HISTORY
GEOLOGIC MODELS
GEOLOGIC STRUCTURES
GEOLOGY
GEOMORPHOLOGY
INDIAN OCEAN
INVERTEBRATES
ISLANDS
ISOTOPE DATING
ISOTOPES
LEVELS
LIGHT NUCLEI
NUCLEI
ORIGIN
QUATERNARY PERIOD
RADIOISOTOPES
REEFS
ROCKS
SEA LEVEL
SEAS
SEDIMENTARY ROCKS
SURFACE WATERS
YEARS LIVING RADIOISOTOPES