RUSSIAN JOURNAL OF EARTH SCIENCES VOL. 10, ES4001, doi:10.2205/2007ES000218, 2008
[87] 1. Zonation of the Atlantic Ocean lithosphere based on cluster analysis involving 10 geological-geophysical parameters, interpreted geodynamically and classifying the lithospheric structure and energy release allowed us to divide the region into four groups of clusters (all in all 15 cluster combinations of parameters). They cannot be established visually using any parameter or their limited combination. The resultant groups exhibit geologically specified features:
[88] 2. Inhomogeneity along the strike of the ridge is an alternation of "hot'' and "cold'' blocks differing greatly in heat flow, total seismic moment, Bouguer anomaly, as used here, signifies the rate of magmatic activity, and tomography by S-waves, marking a degree of the mantle partial melting along with the presence of isolated plumes going deep into the mantle (up to 700 km). The recognized zones correlates well with published data on discreteness of P-T conditions during the formation of the oceanic ridge basalt melts, whose areas are not widely spaced. The above implies superposition of two independent mechanisms for accretion and further dynamics of the oceanic crust in the Mid-Atlantic Ridge zone.
[89] 3. On the Mid-Atlantic Ridge flanks there were recognized zones north-western oriented to major structural elements of the Atlantic, crossing ocean basins, the Mid-Atlantic Ridge and projecting into the continental margins.
[90] 4. Superimposed sublatitudinal phenomena outside of the Mid-Atlantic Ridge refers to zones resulted from eruptive impulses of high rate magmatic activity (sometimes ongoing); they are similar to the recent manifestation of plumes under the Mid-Atlantic Ridge, caused by spreading of pseudosymmetric structures on either side of the ridge. Vestiges of these phenomena inferred from geophysical parameters imply that frequency rate of such manifestations in the Atlantic lithosphere remained, as a whole, unchangeable since the time of its opening.
[91] 5. Another type of sublatitudinal superimposed phenomena is represented by zones marked by a stable distinct combination of high Bouguer and low isostatic anomalies similar to that of the Pacific fore-arc zones. This cluster type correlates in space with anomalous geochemistry of basalts, convergent zones of passive parts of transform faults, sediment anisotropy of ocean basins, and orientation of the western Atlantic subduction zones.
Citation: 2008), Geodynamic zonation of the Atlantic Ocean lithosphere: Application of cluster analysis procedure and zoning inferred from geophysical data, Russ. J. Earth Sci., 10, ES4001, doi:10.2205/2007ES000218.
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