International Geologiical Congress - Oslo 2008


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IEI-12 Geological maps in the digital era: Quo Vadis?


Tectonic zonation of Atlantic Ocean lithosphere resulted from cluster analysis of geological and geophysical parameters


Nikolay Sokolov, Moscow State University (Russian Federation)


The detection of Atlantic Ocean lithosphere heterogeneities was done by multivariate statistical approach (subduction zones were not included into analysis). The calculation is based on 10 geological and geophysical parameters processing by a cluster analysis. The following parameters were considered: sedimentary cover thickness; isostastic anomalies; heat flow; bathymetry; Bouguer anomalies; Love waves tomography; S- and P- wave tomography; magnetic anomalies; total seismic moment.
The procedure of calculation consists of collecting and preprocessing of the data, statistical standardization of data, computing of the stable parameters combinations by K-means cluster analysis method, positioning of results on a map, analysis of the obtained cluster configuration.
15 clusters (stable statistical groups) were detected. They could be aggregated in 4 large groups distinguished from each other by geodynamic conditions: transitional type (ocean - continent - continental margin boundary) - 4 clusters; rift system of a Middle Atlantic Ridge (MAR) - 7 clusters, superimposed patterns - 2 clusters, abyssal plains - 2 clusters.
Spatial data overview shows both known earlier tectonic lithosphere objects, and zones, which existence was in doubt earlier. These are: contrast block zonation of MAR along the ridge axis, zones of clusters, which are widespread on MAR flanks with northwest oblique orientation respect to the main lineament structures of Atlantic crust - ridges and transform faults, crossing abyssal plains and penetrated into continental margins. Also there were fixed the abnormal latitudinal overlapped phenomena, with contrast combination of maximum Bouguer anomalies and minimum isostatic anomalies, which are regularly could be observed at forearc areas of Pacific ocean.
The modified tectonic map of the Atlantic Ocean (scale 1:30000000) based on results mentioned above was compiled.


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