4th International Submarine Canyon Symposium (INCISE2018)
5-7 November 2018, Shenzhen, CHINA
This is the detail of A Morphometric Analysis and Classification of Mediterranean Submarine Canyons
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A Morphometric Analysis and Classification of Mediterranean Submarine Canyons
Submarine canyons are valleys that incise the continental shelf and slope. They play a crucial role in the transfer of sediment and water from the continental shelves to the deep oceans. Previous studies have shown that Mediterranean canyons are morphologically different from those elsewhere. The objective of this study is to investigate this phenomenon by carrying out a detailed morphometric analysis and classification of Mediterranean canyons.
A geodatabase of the canyons was compiled from the literature, 203 canyons were mapped and their attributes were measured and calculated. The results show several correlations between the canyon attributes. Active margin canyons are smaller, shorter, smoother, straighter, shallower and steeper than passive margin canyons. Shelf breaching canyons are rougher, more meandering, wider and deeper than blind canyons. Hack’s Law was successfully applied to the canyons, suggesting that as they grow they elongate. Spatial distribution of canyons, based on their attributes, is controlled by the proximity to terrestrial rivers or the characteristics of the incised continental margin.
The classification of the Mediterranean canyons was investigated using two approaches: data-driven (cluster analysis) and knowledge-driven (ordination analysis). Principal component analysis suggested that area, head depth, axial gradient and rugosity are the most appropriate classifying attributes. The data-driven approach gave a five-cluster classification, but most of the canyons fell into one cluster. The differences between the clusters were considered to be an artefact of the method used to generate the clusters, rather than a consequence of morphological differences. The knowledge-driven approach provided no identifiable groups of canyons. It was concluded that a realistic and predictive classification system could not be devised for the Mediterranean canyons.
This study provides a base for future geomorphological work on Mediterranean canyons, to improve understanding of their origin and evolution, and provides a methodological framework for replicating similar studies worldwide.
Session 3: Patterns and heterogeneity in submarine canyons