Document type
Journal articles
Document subtype
Full paper
Title
Morphotectonics in a low tectonic rate area: Analysis of the southern Portuguese Atlantic coastal region
Participants in the publication
Paula M. Figueiredo (Author)
Thomas K. Rockwell (Author)
João Cabral (Author)
Dep. Geologia
IDL
Cristina Ponte Lira (Author)
Dep. Geologia
IDL
Summary
South Portugal is characterized by low tectonic rates (<0.3 mm/a), with infrequent large seismicity. Recent studies indicate a coastal region in southwest Portugal uplifting at higher rates (0.11 ± 0.01 mm/a) than the remaining southern portion of Portugal (~0.04 mm/a); however, the mechanisms that drive this uplift are poorly understood. With the purpose of investigating the regional Quaternary deformation and its patterns, as well as the difference in the uplift rate, 77 exorheic drainage basins along 460 km of the southern Portuguese coastline were analysed through the application of geomorphic indices. In this study we applied stream channel sinuosity S, basin relief ratio Rh, elongation Re, basin shape ratio Bs, valley height-width ratio V f , basin asymmetry factor AF, hypsometry HI and, the stream-length gradient index SL, and we propose the terminal basin shape index TBS. This study aims to (1) identify Quaternary deformation along presumed tectonic structures; (2) recognize uplift or subsidence along the coastline; and (3) test the application of geomorphic indices in low deformation rate environments. The cross-correlation of results led to the recognition of the São Teotónio-Aljezur-Sinceira fault system and the São Marcos-Quarteira Fault as major regional Quaternary faults, as well as to the interpretation of Quaternary activity for other structures. Spatial differences in uplift rates are identified through basin shape indices and valley height-width ratios, even for low vertical motion rates, whereas other indices were found to be not as sensitive to variations in uplift rate.
Date of Submisson/Request
2017-07-03
Date of Acceptance
2018-02-14
Date of Publication
2019-02
Institution
FACULDADE DE CIÊNCIAS DA UNIVERSIDADE DE LISBOA
Where published
Geomorphology
Publication Identifiers
ISSN - 0169-555X
Publisher
Elsevier BV
Number of pages
19
Starting page
132
Last page
151
Document Identifiers
DOI -
https://doi.org/10.1016/j.geomorph.2018.02.019
URL -
http://dx.doi.org/10.1016/j.geomorph.2018.02.019
Rankings
SCIMAGO Q1 (2019) - 1.384 - Earth-Surface Processes
SCOPUS Q1 (2019) - 6.9 - Earth-Surface Processes
Web Of Science Q1 (2019) - 3.819 - GEOSCIENCES, MULTIDISCIPLINARY - SCIE
Web Of Science Q1 (2019) - 3.819 - GEOGRAPHY PHYSICAL - SCIE
Keywords
Portugal
Uplift
Morphotectonic analysis
Low tectonic rate