Skip to Main Content
Book Chapter

Upstream controls on evolution of dryland alluvial megafans: Quaternary examples from the Kohrud Mountain Range, central Iran

By
Nasser Arzani
Nasser Arzani
1
Geology Department, Payme Noor University, P.O. Box 19395-469, Tehran, Islamic Republic of Iran
Search for other works by this author on:
Stuart J. Jones
Stuart J. Jones
2
Department of Earth Sciences, Durham University, South Road, Durham DH1 3LE, UK
Search for other works by this author on:
Published:
January 01, 2018

Abstract

The relative importance of tectonics, climate, base level and source lithology as the primary controls on the evolution of alluvial fans is highly debated. This study examines the role of upstream catchment characteristics on the evolution of alluvial megafans by examining three Quaternary fans (the Kalahrud, Zefreh and Mughar fans) along the flanks of the Kohrud Mountain Range in central Iran. These fans formed in a tectonically active basin under arid to semi-arid climatic conditions. The key differences between the evolutionary trends of these fans are that their catchments are underlain by different bedrock types and they have different catchment shapes and outlet characteristics. The catchment of the Kalahrud fan is in a sedimentary terrain with limited sediment supply, whereas the bedrock lithologies of the Zefreh and Mughar fans are fractured and weathered igneous rocks. However, the evolution of the Mughar fan is also controlled by the tilting of the catchment towards a wide apex and lateral shifting in the catchment outlet/fan feeder channel position. These variables resulted in relatively large-scale incision in the Kalahrud and Mughar fans that is absent in the aggradational trend of the Zefreh fan. Upstream lithological and structural controls are the dominant drivers behind the development and evolution of alluvial megafans.

You do not currently have access to this article.

Figures & Tables

Contents

Geological Society, London, Special Publications

Geology and Geomorphology of Alluvial and Fluvial Fans: Terrestrial and Planetary Perspectives

D. Ventra
D. Ventra
Utrecht University, the Netherlands
Search for other works by this author on:
L. E. Clarke
L. E. Clarke
University of Gloucestershire, UK
Search for other works by this author on:
Geological Society of London
Volume
440
ISBN electronic:
9781786203809
Publication date:
January 01, 2018

GeoRef

References

Related

Citing Books via

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal