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(Article of periodic en Anglais - 2013)

Document title

Threshold of erosion of submarine bedrock landscapes by tidal currents

Authors(s) and Affiliation(s)

MITCHELL N.C. (1) ; HUTHNANCE J.M. (2) ; SCHMITT T. (3) ; TODD B. (4) ;
(1) School of Earth, Atmospheric and Planetary Sciences, univ., Manchester, ROYAUME-UNI
(2) National Oceanography Centre, Proudman Oceanographic Lab., Liverpool, ROYAUME-UNI
(3) Service Hydrographique et Océanographique de la Marine, Brest, FRANCE
(4) Geological Survey of Canada (Atlantic), Natural resources, Dartmouth, CANADA

Abstract

The AA. examine multibeam sonar datasets from areas of extreme tidal currents to see if there is any evidence for erosion of bedrock. A dataset of shear stresses beneath typically strong tidal currents is developed and compared with a dataset for bedrock-eroding rivers. In the Minas Passage (Bay of Fundy), Canada, the Bristol Channel off Nash point, UK, and in the Straits of Messina, Italy, sonar data are collected and discussed. Holocene tidal currents have apparently been generally ineffective at eroding bedrock. The AA. examine this issue further by compiling extreme tidal streams around the UK and from them estimate shear stresses, representing a macro-tidal environment where peak surface currents reach 9-7 knots. Those data are compared with shear stresses in mountainous rivers where long-term rates of erosion are comparable with tectonic uplift rates and are thus geomorphologically significant. The vertical faces in the Minas Passage may represent the onset of abrasion. Given this limited evidence for abrasion, the AA. explore conditions in the geological past for tides that may have locally eroded bedrock

Source

Article of periodic

published at : Earth surface processes and landforms / ISSN 0197-9337 / CODEN ESPLDB

Editor : Wiley, Chichester - ROYAUME-UNI (1981)

Millesime : 2013, vol. 38, no6 [pp. 627-639]

Bibliographic references : 2 p.

Collation : 10 fig., 1 tabl.

Language

Anglais

INIST-CNRS, Cote INIST : 17355

Digital Object Identifier

Go to electronic document thanks to its DOI : doi:10.1002/esp.3347

Tous droits réservés © Prodig - Bibliographie Géographique Internationale (BGI), 2014
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