Геологія і корисні копалини Світового океану (Apr 2019)

MORPHOSTRUCTURE OF ATLANTIC’S BOTTOM AND MEDIUM ATLANTIC RIDGE

  • A.M. Zhirnov

DOI
https://doi.org/10.15407/gpimo2019.01.047
Journal volume & issue
Vol. 15, no. 1
pp. 47 – 62

Abstract

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The purpose of the study is to characterize the morphostructure and geology of Atlantic's bottom and the Mid Atlantic Ridge using generalized and new data. The basis is the bathymetric map of the Atlantic 1971, according to research data of the Institute of Oceanology. P.P. Shirshov, and publications of the XX—XXI centuries. The morphostructure of the Atlantic's bottom and Mid Ridge is determined by the curved position of the eastern part of the American continent, the lower metabasaltic layer of which originated in Hadean. Accordingly, the main longitudinal dislocations of the bottom and ridge arose in Hadean, but their development took place at different times of the Precambrian and the Mesozoic. In particular, the Ocean began to form in the Late Cretaceous. The median ridge was formed in the Proterozoic Paleozoic time and consists of two complexes of rocks — the lower ancient and the upper young. Its actual length is 11,600 km, between the Hudson Biscay Fault in the north and the Falkland Fault in the south. The ridge was formed in the intervals between the latitudinal Archean faults by uneven swelling (vertical ascent) of igneous rocks composing it. Therefore, different segments of the ridge have a different strike and width. In some places, 200—400 km wide, there is no ridge. In the Cenozoic, the range descended into the ocean. The central rift graben ridge has a total length of 3200 km — one quarter of the total length of the ridge. Volcanoes and seismicity are distributed along the margins of the Atlantic, due to the young submarine ridges and archipelagos of the islands. Within the limits of the Sredinny Range, their number is three times less than in the remaining area of the Atlantic's bottom. The obtained generalizing results correspond to the status of the reality of the world level of significance.

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