Geological structure of the Kashevarov Trough (central Sea of Okhotsk)

• Published in: Russian journal of Pacific geology Vol. 5; no. 5; pp. 387 - 399
• Main Authors: Lelikov, E. P., Tsoy, I. B., Vagina, N. K., Emel’yanova, T. A., Terekhov, E. P., Khudik, V. D.
• Format: Journal Article
• Language: English
• Published: Dordrecht SP MAIK Nauka/Interperiodica 01-10-2011; Springer Nature B.V
• Subjects: Cenozoic; Cretaceous; Earth and Environmental Science; Earth Sciences; Eocene; Geological structures; Geology; Mesozoic; Miocene; Oligocene; Pleistocene; Pliocene; Rocks; Sedimentary geology; Shallow water; Volcanic belts; Volcanoes; Sea of Okhotsk; INW, Okhotsk Sea; Kashevarov Trough; Sea of Okhotsk; granitoids; volcanics; Oligocene; diatoms; Eocene; Cenozoic sedimentary cover; Late Cretaceous; palynoflora
• ISSN: 1819-7140; 1819-7159
• DOI: 10.1134/S1819714011050046

This paper reports the composition and age of rocks dredged from the Kashevarov Trough (central Sea of Okhotsk) during cruise 41 of the R/V
Akademik M.A. Lavrentyev
in 2006. It was found that the Late Cretaceous and Eocene volcanics from the Kashevarov Trough and Okhotsk-Chukotka volcanic belt, structures of which are traceable in the Sea of Okhotsk, have similar petrographic and geochemical features. The Cenozoic sedimentary cover consists of three different-age complexes: (1) the late Oligocene (∼28.2–24.0 Ma); (2) the terminal late Oligocene-early Miocene (24.0–20.3 Ma); (3) the terminal late Pliocene-early Pleistocene (2.0–1.0 Ma). The upper Oligocene-lower Miocene sediments were deposited in relatively shallow-water settings, whereas the late Pliocene-early Pleistocene complex was formed in deeper environments, which was probably determined by tectonic processes. The geological data indicate that the Kashevarov Trough and the surrounding underwater rises represented in the Oligocene-early Miocene a single shelf zone of the Sea of Okhotsk, which is underlain by a structurally integral Mesozoic basement and is now subsided to depths of 800–1000 m.