Isolating lithologic versus tectonic signals of river profiles to test orogenic models for the Eastern and Southeastern Carpathians

Fluvial morphology is affected by a wide range of forcing factors, which can be external, such as faulting and changes in climate, or internal, such as variations in rock hardness or degree of fracturing. It is a challenge to separate internal and external forcing factors when they are co-located or...

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Bibliographic Details
Published inEarth and Space Science Open Archive ESSOAr
Main Authors Gailleton, Boris, Hugh Denny Sinclair, Mudd, Simon Marius, Graf, Emma L, Matenco, Liviu
Format Paper
LanguageEnglish
Published Washington American Geophysical Union 07.12.2020
Subjects
Climate change
Concavity
Fluvial morphology
Geological data
Geology
Hardness
Lithology
Mathematical analysis
Morphology
Orogeny
Rocks
Slopes
Tectonics
Uplift
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Summary:Fluvial morphology is affected by a wide range of forcing factors, which can be external, such as faulting and changes in climate, or internal, such as variations in rock hardness or degree of fracturing. It is a challenge to separate internal and external forcing factors when they are co-located or occur coevally. Failure to account for both factors leads to potential misinterpretations. For example, steepening of a channel network due to lithologic contrasts could be misinterpreted as a function of increased tectonic displacements. These misinterpretations are enhanced over large areas, where landscape properties needed to calculate channel steepness (\textit{e.g.} channel concavity) can vary significantly in space. In this study, we investigate relative channel steepness over the Eastern Carpathians, where it has been proposed that active rock uplift in the Southeastern Carpathians gives way N- and NW-wards to ca. 8 Myrs of post-orogenic quiescence. We develop a technique to quantify relative channel steepness based on a wide range of concavities, and show that the main signal shows an increase in channel steepness from east to west across the range. Rock hardness measurements and geological studies suggest this difference is driven by lithology. When we isolate channel steepness by lithology to test for ongoing rock uplift along the range, we find steeper channels in the south of the study area compared to the same units in the North. This supports interpretations from longer timescale geological data that active rock uplift is fastest in the southern Southeastern Carpathians.
DOI:10.1002/essoar.10505201.1