Crustal Control of Ridge Segmentation Inferred from Observations of the Reykjanes Ridge

Publication Type  Journal Article
Year of Publication  1992
Authors  Bell, R. E.; Buck, W. R.
Journal Title  Nature
Volume  357
Issue  6379
Pages  583-586
Journal Date  Jun 18
ISBN Number  0028-0836
Accession Number  ISI:A1992HZ11200051
Key Words  mid-atlantic ridge

LARGE-AMPLITUDE variations in topography and inferred crustal thickness along the axes of mid-ocean ridges, often referred to as segmentation 1, are mainly observed at slow-spreading ridges 2-4. This observation has led to the suggestion that mantle processes give rise to segmentation only when spreading rates are lows 5,6. Here we make the alternative proposal that the development of segmentation is controlled by the temperature of the crust: segmentation cannot develop when the lower crust is hot enough to undergo rapid ductile flow. Thermal models predict that thick crust at a slow-spreading ridge may be as hot as normal-thickness crust along fast-spreading ridges; we accordingly test our hypothesis at a slow-spreading ridge characterized by thick crust-the Reykjanes Ridge. Topography and gravity data along the Reykjanes Ridge axis indeed show an absence of segmentation, suggesting that the thermal state of the crust, rather than any mantle process, controls the development of this structure.


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URL  <Go to ISI>://A1992HZ11200051