| The rhythmicity of Cretaceous paleoceanic deposits |
O.L. Savelyeva Institute of Volcanology and Seismology FEB RAS, Petropavlovsk-Kamchatsky, 683006 This article considers the problem of rhythmicity origin in oceanic deposits of Cretaceous age in various regions. The article contains discussions on different models of rhythmicity origin. Besides, features of rhythmical layered deposits of Albian – Cenomanian age on the Kamchatsky Mys peninsula (Eastern Kamchatka) are considered in detail. In those deposits rhythmicity of two orders with a ratio 1:5 is observed. In order to explain this rhythmicity the author used a model of dependancy of sedimentation features on paleoclimate fluctuations connected to Milankovitch cycles. An intermediate link are trade winds increasing of which increases ocean water circulation and raises bioproductivity. The paper shows that rhythmicity of Cretaceous pelagic marl-limestone and siliceous-carbonate deposits in the majority of sections of the world is also connected to Milankovitch cycles. |
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