Seamount Abundances and Distribution Near the East Pacific Rise 0°-24°N Based on Seabeam Data

  1. Barbara H. Keating,
  2. Patricia Fryer,
  3. Rodey Batiza and
  4. George W. Boehlert
  1. Daniel J. Fornari1,
  2. Rodey Batiza2 and
  3. Mary Ann Luckman1

Published Online: 18 MAR 2013

DOI: 10.1029/GM043p0013

Seamounts, Islands, and Atolls

Seamounts, Islands, and Atolls

How to Cite

Fornari, D. J., Batiza, R. and Ann Luckman, M. (1987) Seamount Abundances and Distribution Near the East Pacific Rise 0°-24°N Based on Seabeam Data, 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/GM043p0013

Author Information

  1. 1

    Lamont Doherty Geological Observatory, Columbia University, Palisades, NY 10964

  2. 2

    Department of Geological Sciences, Northwestern University, Evanston, IL 60201

Publication History

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

ISBN Information

Print ISBN: 9780875900681

Online ISBN: 9781118664209

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Keywords:

  • Seamounts;
  • Coral reefs and islands

Summary

We have used 10,240 line kilometers of Seabeam data to study the sizes, abundances and distribution of seamounts near the East Pacific rise (EPR) from the equator to 24°N on lithosphere <10 Ma. We find 168 volcanoes with heights over 50 m in this study area of 18,400 km2 for a mean seamount abundance of about 9000 seamounts/106 km2 or 1.5 million seamounts for the Pacific assuming constant production rates. Abundances in 49 undivided 1°×1° areas vary widely from values of zero to over 66,000 seamounts/106km2 after linear adjustment for percent of area coverage in each 1° square. This indicates highly nonuniform distribution and, in fact, most seamounts are clustered near transform and fracture zones, some large overlapping spreading centers (OSCs) and swollen elevated portions of the EPR. Seamount abundance within 50 km of the EPR is about 10,000±6000/106km2 and does not seem to change significantly out to 550 km from the EPR crustal age (4–9 Ma). Size frequency distribution shows similar patterns for 0–0.5 Ma and 0.5–1.0 Ma sea floor, with 70–80% of the volcanoes being smaller than 0.1 km3 (<100 m high); on older crust, however, only about 45% are in this small size class. If representative, these data indicate that most small seamounts are produced very near the EPR and some may continue to grow as they drift away, in agreement with previous geologic, petrologic, magnetic and radiometric age evidence. This study provides further evidence that seamount production is strongly linked to tectonic and petrologic processes at the EPR near major transform offsets and possibly at some large OSCs. Our data seem to indicate that seamount production on lithosphere <10 Ma occurs almost exclusively very near the EPR axis, which contrasts with earlier findings of a relationship between seamount production and lithosphere age. We attribute this disagreement, in part, to the strong age bias of the data set used in this study, but this disagreement points to the need for more field studies and data to resolve the question of the extent to which seamount production is related to lithosphere age and plate boundary processes.