Results of Studying the Material Composition and U-Pb (LA-ICP-MS) Age of Detrital Zircons From Terrigenous Rocks of the Vanavara and Oskobinskaya Formations of the Kamov Arch of the Baikit Antelise
Results of Studying the Material Composition and U-Pb (LA-ICP-MS) Age of Detrital Zircons From Terrigenous Rocks of the Vanavara and Oskobinskaya Formations of the Kamov Arch of the Baikit Antelise
Blog Article
The paper presents the results of studies on sandstones from the Vanavara and Oskobinskaya formations, which are part of the Nepa and Torskiy regional stratigraphic horizons, respectively.These formations were studied using the core from the Yur-92 deep well, located within the Kamov Arch of the Baikit Anteclise on the Siberian Platform.A detailed lithological description of a core with a total thickness of 89 meters is provided.For 13 sandstone samples, the following studies were conducted: petrographic analysis of thin sections, definition of major petrogenic oxide content, definition of impurity and trace element content using mass spectrometry with inductively coupled plasma, and geochronological (U-Pb) analysis of detrital zircon grains.It was found that the Vanavara formation is characterized by a terrigenous composition, while the Oskobinskaya formation is composed of terrigenous, read more sulfate, and carbonate rocks and can be divided into three members.
According to the results of petrographic analysis of rocks from the Vanavara and Oskobinskaya formations, there is generally a similarity in terms of the degree of roundness and sorting of detrital material, as well as the composition of both rock-forming and accessory minerals including rock fragments such as quartzites, micaschists, and granitoids (both metamorphic and igneous rock types), as well as clay rocks, likely argillites.The material composition of all the studied sandstones from the Vanavara and Oskobinskaya formations corresponds to that of arkoses.Based on a set of lithogeochemical characteristics, it appears that the source material for the deposits of the Vanavara formation was primarily derived from here rocks with an acidic composition, while the terrigenous rocks from the Oskobinskaya formation may have originated from both acidic and intermediate rocks.U-Pb (LA-ICP-MS) dating of detrital zircon grains from terrigenous rocks of the Vanavara Formation indicates that the main source of sediments in the basin where they were deposited was Archean and Early Proterozoic rocks from the Siberian Platform basement.The Oskobinskaya Formation was deposited as a result of the erosion of Archean, Early Proterozoic, and late Riphean rocks that formed the basement of the Siberian platform and the northern segment of the Central Asian fold belt, as well as possibly rocks that make up the East Angara Block of the Yenisei Ridge.
Based on the characteristics of the Vanavara and Oskobinskaya formations, combined with the results of zircon dating and published data on lithofacies, it is suggested that the Vanavara formation was deposited on the passive margin of the Siberian platform.Then, there was a transformation into a peripheral foreland basin in which terrigenous rocks from the Oskobinskaya formation accumulated.