Sedimentogenesis in Maastrichtian-Danian basins of the Russian plate and adjacent areas in the context of plume geodynamics

Abstract

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.

Metallic iron in sediments at the Mesozoic-Cenozoic (K/T) boundary

“…The content of metallic iron in this layer from the five separated sections varies widely: it is absent or, more precisely, has not been detected by TMA, in 19 samples out of 28 studied and varies from 0.0001 to 0.002% in the remaining nine samples [Grachev et al, 2005;Molostovsky et al, 2006;Pechersky, 2008;Pechersky et al, 2006aPechersky et al, , 2006b]; (D. M. Pechersky et al, in press, 2008a,b). A detailed imbedded study of the boundary layer from the Gams section showed that metallic iron is present only in the upper and lower parts of this layer (Figure 1).…”

“…Correlation between paramagnetic magnetization (Mp) and concentration of ferromagnetic Fe-hydroxides (goethite), magnetite, titanomagnetite, and metallic iron in sediments. The data for the Gams, Koshak, Klyuchi, Teplovka, Tetritskaro, and Khalats sections are combined [Molostovsky et al, 2006;Pechersky et al, 2006aPechersky et al, , 2006bPechersky, 2008]; (D. M. Pechersky et al, in press, 2008a,b). particles of terrestrial origin; and "secondary" as a result of subsequent oxidation of metallic iron particles with formation of Fe-hydroxides and hematite.…”

“…Rather high and practically the same positive correlations are between the logarithms of metallic iron, paramagnetic magnetization, and the goethite content, while the correlation Figure 8. Correlation between paramagnetic magnetization (Mp), concentration of ferromagnetic Fehydroxides (goethite), magnetite, titanomagnetite, and metallic iron in sediments from the Klyuchi and Teplovka sections [Molostovsky et al, 2006;Pechersky, 2008].…”

“…This paper is the first attempt to review TMA data on the distribution of metallic iron in several sections [Adamia et al, 1993;Grachev et al, 2005;Molostovsky et al, 2006;Pechersky, 2008;Pechersky et al, 2006aPechersky et al, , 2006b]; (D. M. Pechersky et al, in press, 2008a,b).…”

Metallic Iron and Nickel in Cretaceous and Cenozoic Sediments: The Results of Thermomagnetic Analysis

“…Modern data on distribution of native iron and nickel in the cosmic dust is rather limited, since only "direct" methods of detecting such particles were used. Thermomagnetic analysis (TMA) up to 800ºC was employed during petromagnetic (rock-magnetic) studies of sediments [1][2][3][4][5][6][7]. The increase of ТMA temperature interval by 100 о has given the chance to observe a detailed picture of a distribution of metallic iron in space and time.…”