The effect of boulders on shore platform development and morphology in Galicia, north west Spain

• Type: Article in International Scientific Journal
• Date: 2012

Authors

Perez-Aalberti, A (Author) Other; Trenhaile, A. S. (Author) Other; Pires, A. (Author) Other; Lopez-Bedoya, J (Author) Other; Chamine, Helder I. (Author) Other; Gomes, António Alberto (Author) FLUP

Journal

Title: Continental Shelf Research

Vol. 48

Pages: 122-137

ISSN: 0278-4343

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 23 Citations

ISI Web of Science

Scopus - 26 Citations

Scientific classification

FOS: Natural sciences > Earth and related Environmental sciences

CORDIS: Natural sciences

Other information

Authenticus ID: P-002-4NS

DOI: 10.1016/j.csr.2012.07.014

Abstract (EN): This paper is concerned with the effect of sediment accumulation on shore platform development. Boulder accumulations are common on the granitic shore platforms of Galicia, northwestern Spain. Boulders are produced by erosion of shore platforms and of cliffs consisting of cold-climate deposits from the last glacial period. Measurements were made of the long axis length of more than 800 boulders, and additionally of the short and intermediate axes of 340 of these boulders, as well as of their orientation and gradient. There were two study areas. The boulders on the Barbanza Peninsula are generally a little smaller than those in southern Galicia with, respectively; mean long axis lengths of 0.98 and 1.14, and masses of 1.06 and 1.59 t. There are also some isolated, very coarse boulders and megaclasts in southern Galicia. The distribution and extent of the deposits and boulder imbrication and orientation testify to the high levels of wave energy produced by northwesterly and westerly storms in this region. Although the boulders, as well as the underlying shore platforms, were inherited, in part, from previous interglacial stages, some boulder detachment and movement is occurring today during storms, when significant deep water wave heights exceed 8 to 10 m. Despite some abrasion of the shore platforms, the primary effect of large boulder accumulations is protective. The role of sediment on shore platforms has been neglected, but this study suggests that because of arrested development under thick accumulations, platform gradient in areas with abundant sediment increases with the grain size of the material. The occurrence and type of sediment on shore platforms may therefore help to explain the distribution of sloping and subhorizontal platforms under different morphogenic and geological conditions. (C) 2012 Elsevier Ltd. All rights reserved.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 16