The sediment composition and sedimentation conditions of Maastrichtian and Danian deposits in the vast territory of the Russian plate and adjacent regions of North Eurasia were studied. The succession of Late Cretaceous carbonaceous conditions of sedimentation in the Early Paleocene is noted in the major part of North Eurasia sedimentary basins. In some areas of the Lower Volga region and of the Northern Cis-Caspian basin, a radical change occurred in the sedimentation conditions at the Cretaceous-Paleogene boundary: Lower Paleocene siliceous formation replaced Maastrichtian carbonaceous formations. It is assumed that in this case the silica mass delivery into the basin was caused by tectonic rejuvenation of faults system at the border between the Russian platform and the Cis-Caspian basin under the large impact events. At the Maastrichtian-Danian boundary and above in the Danian, the increase of magnetic susceptibility of rocks is commonly noted for the major part at the expense of enrichment of rocks with iron in paramagnetic compounds (ferric hydrooxide and iron-containing clayey minerals) similar to metal-bearing sediments and to a lesser degree at the transport of terrigenous material addition in the period of large Early Paleocene regression. In the sediments, microspherules of metallic iron are noted that are most likely of cosmic meteoric dust.
mantle plumes, K/T boundary, sediments, petromagnetism, magnetic susceptibility, paramagnetic magnetization, metallic iron, Russian plate.
1. Akhlestina, The Atlas of Cretaceous and Paleogene Siliceous Rocks of Povolzh'e, 2000.
2. Akhlestina, Upper Cretaceous and Paleogene Silicites of the Povolzh'e, 1998.
3. Akhlestina, Voprosy Geologii Yuzhnogo Urala i Povolzh'ya, issue 18, 1979.
4. Akhlestina, Eocene ash sediments of Saratov and Volgograd Povolzh'e regions, 1988.
5. Alexeev, Bulletin de l'Institute Royal des Sciences Naturelles de Belgique, Sciences de la Terre, v. 69-supp., 1999.
6. Ellwood, EPSL, v. 206, 2003.
7. Grachev, Phys. Solid Earth, v. 36, no. 4, 2000.
8. Grachev, Russ. J. Earth Sci., v. 7, 2005., doi:https://doi.org/10.2205/2005ES000189
9. Gurvich, Metal-Bearing Sediments of the World Ocean, 1998.
10. Guzhikov, Cretaceous-Palaeogene tectonic activity in the Caucasus and Trans-Caucasia reflected in scalar magnetic characteristics, 1998.
11. Molostovsky, The Use of Rock Magnetism in Geological Survey, edited by L. E. Sholpo, B. Sh. Rusinov, M. G. Ilaev, 1986.
12. Molostovsky, Magnetostratigraphy and Its Significance in Geology, 1997.
13. Muraviev, Lithology and Useful Minerals, v. 3, 1997.
14. Musatov, Voprosy Stratigrafii Povolzh'ya I Prikaspiya: Collection of Scientific Papers, 2004.
15. Nikishin, Geohystorical and geodynamical analysis of sediment basins, 1999.
16. Pechersky, Russ. J. Earth Sci., v. 7, no. 2, 2005.
17. Pechersky, Phys. Solid Earth, v. 42, no. 11, 2006.
18. Rikhter, Essays of Regional Geodynamics of the Cis-Caspian Basin and Its Framing, 2003.
19. Veymarn, Global Catastrophical Events and Their Role in Stratigraphic Correlations of Sedimentary Basins of Various Types, 1998.
20. Yampolskaya, Preliminary results of the magnetic properties research of the Cretaceous--Paleogene boundary sediments in the Crimea mountainous area, 2004.
