Reconstructing Basin Evolution Through Unconformities: Hiatus Mapping Across the Northern Alpine Foreland Basin

Abstract

Tectonic theories that were proposed in the late nineteenth and the twentieth centuries have helped the horizontal movements of the lithosphere to be explored and understood on a global scale. The vertical lithospheric movements, on the other hand, have remained understudied and are open to further analysis. While thermochronology, radiometric dating, stable isotope analysis, geohistory analysis, and geodetic measurements have been useful in shedding light on many aspects of the phenomena, some of these methods have certain limitations in the evaluation of large-scale vertical movement of earth’s surface over longer time periods.

This study assesses the vertical lithospheric movements that have taken place during the evolution of the German portion of the Northern Alpine Foreland Basin (NAFB) by employing a newly devised method. The “Hiatus Mapping” technique renders it possible to investigate such motions and the processes responsible through a systematic representation of the unconformities across the basin fill. The procedure includes construction of hiatus contour maps of the basin through quantification of the missing time that is represented at unconformity surfaces. The results of this study are the hiatus maps of the German portion of the NAFB in seven sequential time slices since Chattian time. The basin evolution and subsidence history inferred from the hiatus maps reveal the influence of Alpine tectonics on the tectonostratigraphic evolution of its foreland. The findings are consistent with the existing literature on the Northern Alpine Foreland Basin and validate the new method herein. Therefore, we suggest that the use of hiatus maps might help to visualize processes that existing methods have not been able to reveal.

Keywords: Hiatus, Unconformities, Northern Alpine Foreland Basin, NAFB, Molasse, Tectonics, Lithosphere, Uplift, Subsidence

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018