Marine Geophysical Researches

, Volume 23, Issue 5, pp 443–469

Geology of the Atlantis Massif (Mid-Atlantic Ridge, 30° N): Implications for the evolution of an ultramafic oceanic core complex

  • Donna K. Blackman
  • Jeffrey A. Karson
  • Deborah S. Kelley
  • Johnson R. Cann
  • Gretchen L. Früh-Green
  • Jeffrey S. Gee
  • Stephen D. Hurst
  • Barbara E. John
  • Jennifer Morgan
  • Scott L. Nooner
  • D. Kent Ross
  • Timothy J. Schroeder
  • Elizabeth A. Williams
Article

DOI: 10.1023/B:MARI.0000018232.14085.75

Cite this article as:
Blackman, D.K., Karson, J.A., Kelley, D.S. et al. Marine Geophysical Researches (2002) 23: 443. doi:10.1023/B:MARI.0000018232.14085.75

Abstract

The oceanic core complex comprising Atlantis Massif was formed within the past 1.5–2 Myr at the intersection of the Mid-Atlantic Ridge, 30° N, and the Atlantis Transform Fault. The corrugated, striated central dome prominently displays morphologic and geophysical characteristics representative of an ultramafic core complex exposed via long-lived detachment faulting. Sparse volcanic features on the massif's central dome indicate that minor volcanics have penetrated the inferred footwall, which geophysical data indicates is composed predominantly of variably serpentinized peridotite. In contrast, the hanging wall to the east of the central dome is comprised of volcanic rock. The southern part of the massif has experienced the greatest uplift, shoaling to less than 700 m below sea level, and the coarsely striated surface there extends eastward to the top of the median valley wall. Steep landslide embayments along the south face of the massif expose cross sections through the core complex. Almost all of the submersible and dredge samples from this area are deformed, altered peridotite and lesser gabbro. Intense serpentinization within the south wall has likely contributed to the uplift of the southern ridge and promoted the development of the Lost City Hydrothermal Field near the summit. Differences in the distribution with depth of brittle deformation observed in microstructural analyses of outcrop samples suggest that low-temperature strain, such as would be associated with a major detachment fault, is concentrated within several tens of meters of the domal surface. However, submersible and camera imagery show that deformation is widespread along the southern face of the massif, indicating that a series of faults, rather than a single detachment, accommodated the uplift and evolution of this oceanic core complex.

Supplementary material

APp.5255353_1.pdf
Supplementary material

Copyright information

© Kluwer Academic Publishers 2002

Authors and Affiliations

  • Donna K. Blackman
    • 1
  • Jeffrey A. Karson
    • 2
  • Deborah S. Kelley
    • 3
  • Johnson R. Cann
    • 4
  • Gretchen L. Früh-Green
    • 5
  • Jeffrey S. Gee
    • 1
  • Stephen D. Hurst
    • 6
  • Barbara E. John
    • 7
  • Jennifer Morgan
    • 4
  • Scott L. Nooner
    • 1
  • D. Kent Ross
    • 8
  • Timothy J. Schroeder
    • 7
  • Elizabeth A. Williams
    • 2
  1. 1.Scripps Institution of OceanographyLa JollaUSA
  2. 2.Division of Earth & Ocean SciencesDuke UniversityDurhamUSA
  3. 3.School of OceanographyUniversity of WashingtonSeattleUSA
  4. 4.Department of Earth SciencesUniversity of LeedsLeedsUK
  5. 5.Institut fur Mineralogie & PetrographieETH-ZentrumZurichSwitzerland
  6. 6.Department of GeologyUniversity of IllinoisUrbanaUSA
  7. 7.Department of Geology and GeophysicsUniversity of WyomingLaramieUSA
  8. 8.Department of Geology & GeophysicsUniversity of HawaiiHonoluluUSA

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