A 3-D Gravity-Tectonic Study of Ita Mai Tai Guyot: An Uncompensated Seamount in the East Mariana Basin

  1. Barbara H. Keating,
  2. Patricia Fryer,
  3. Rodey Batiza and
  4. George W. Boehlert
  1. Bruce Wedgeworth and
  2. James Kellogg

Published Online: 18 MAR 2013

DOI: 10.1029/GM043p0073

Seamounts, Islands, and Atolls

Seamounts, Islands, and Atolls

How to Cite

Wedgeworth, B. and Kellogg, J. (1987) A 3-D Gravity-Tectonic Study of Ita Mai Tai Guyot: An Uncompensated Seamount in the East Mariana Basin, in Seamounts, Islands, and Atolls (eds B. H. Keating, P. Fryer, R. Batiza and G. W. Boehlert), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM043p0073

Author Information

  1. Hawaii Institute of Geophysics, Honolulu, Hawaii 96822

Publication History

  1. Published Online: 18 MAR 2013
  2. Published Print: 1 JAN 1987

ISBN Information

Print ISBN: 9780875900681

Online ISBN: 9781118664209



  • Seamounts;
  • Coral reefs and islands


Ita Mai Tai is a large, locally uncompensated seamount on the eastern edge of the East Mariana Basin. A large positive gravity anomaly of 254 mgal characterizes the summit and a low of −69 mgal, the surrounding moat. Using polygonal prisms to approximate the bathymetry, the observed gravity was inverted to calculate an average density of 2.59 g/cm3 for the seamount. Observed-calculated gravity residuals are reduced by including the flanking sedimentary basins and a dense volcanic conduit. The drill sites from DSDP Legs 20 and 89 describe a volcanic edifice formed in the Aptian/Albian on Jurassic/Cretaceous crust. The volcanism is recorded in volcanoclastic and epiclastic deposits in the basins nearby. The guyot was covered initially by a succession of reefal and lagoonal sediments followed by a thick mantling of pelagic sediments after it subsided. Gravity models that adequately match the calculated and observed data sets for Ita Mai Tai show little crustal thickening, suggesting that Ita Mai Tai is almost completely locally uncompensated.