Search

Your search keyword '"Leitchenkov, G. L."' showing total 33 results
Start Over Author "Leitchenkov, G. L."
33 results on '"Leitchenkov, G. L."'

24. Evolution of the Sedimentary Basin of the Continental Margin of Antarctica in the Cooperation Sea (from Results of Numerical Modeling).

Author

Leitchenkov, G. L., Galushkin, Yu. I., Guseva, Yu. B., and Dubinin, E. P.

Subjects
CONTINENTAL margins, CONTINENTAL shelf, CRUST of the earth, SEAS, STRATIGRAPHIC geology, LITHOSPHERE, SEDIMENTARY basins
Abstract

We discuss the structure of the Earth's crust the seismic stratigraphy, thermal evolution, and stretching of the lithosphere in the sedimentary basin of the Cooperation Sea located on the continental margin of Antarctica in the south of the Indian Ocean. The sedimentary basin includes intracontinental and marginal rifts; the former is located on the shelf, and the latter, in the deep-water area. A seismostratigraphic analysis has revealed four sequences in the sedimentary cover of the intracontinental rift, which formed from middle Permian to late Cenozoic, and nine sequences in the sedimentary cover of the marginal rift, which have been deposited since the Middle Jurassic. One-dimensional numerical modeling of the thermal regime and the basement subsidence was performed over 18 points along the profile crossing the basin from the shelf to the lower continental rise. Based on the results of modeling and seismostratigraphic analysis, we have established variations in rock temperature with depth and in the degree of lithosphere stretching throughout the basin rift history. The modeling showed that the depth of the basement subsidence and the thickness of the crystalline part of the basin crust are governed by the lithosphere stretching before sedimentation. The maximum stretching is reached at the depocenters of rift structures (where the crust is the thinnest), being 2.8 before sedimentation and 1.16 after it in the intracontinental rift and 4.6 and 1.4, respectively, in the marginal rift. [ABSTRACT FROM AUTHOR]

Published
2020

29. From sediment sink to erosion source: reconstructing Antarctic palaeotopography at the Eocene-Oligocene climate transition

Author

Jamieson, S. S. R., Wilson, D. S., Barrett, P. J., Siddoway, C. S., Gohl, Karsten, Larter, R. D., Leitchenkov, G. L., Jamieson, S. S. R., Wilson, D. S., Barrett, P. J., Siddoway, C. S., Gohl, Karsten, Larter, R. D., and Leitchenkov, G. L.

Abstract

The ability of models to elucidate climate and ice sheet dynamics at the Eocene-Oligocene climate transition (34 Ma) is limited by a reliance on present-day topography as a boundary condition. We present a reconstruction of the Antarctic palaeotopography at the E-O boundary that restores sediment eroded from the continent. Estimates of sediment volume surrounding Antarctica constrain our restoration. Using data from coring and seismic imaging and allowing for a moderate biogenic fraction, weathering reactions and sediment porosity, a source volume of 5-13 million cubic km is thought to have been removed from an area of ca. 13 million square km. Changes to the East Antarctic landscape by local, regional and continental-scale ice have been estimated using an ice sheet and erosion model. Material is restored in response to basal conditions under a range of modelled ice-sheet configurations. These models can restore 3-4 million cubic km to East Antarctica. In West Antarctica, factors including the variable position of the grounding line make it impractical to use quantitative erosion models. Here we link geological evidence for known or suspected remnants of Eocene topography with our understanding of processes and patterns of erosion and deposition to drive construction of potential surfaces. There are several options for geologically reasonable surfaces that imply 5-10 million cubic km of eroded volume. The uncertainty in eroded volume is muted by the transformation to palaeo-elevation because isostatic compensation generally limits the change in average regional elevation to 15-20% of the thickness eroded.

Published
2010

Catalog

Books, media, physical & digital resources
See catalog results