Please use this identifier to cite or link to this item: http://hdl.handle.net/10216/75351
Author(s): Araújo, Maria da Assunção
Gomes, António Alberto
Title: The Use of the GPS in the Identification of Fossil Shore Platforms and its Tectonic Deformation: an Example from the Northern Portuguese Coast.
Issue Date: 2009
Abstract: Since more than 20 years we have the strong impression that recent tectonics may be active in the northern coastal zone of Portugal. This assumption is compatible with several recent studies on this matter. However, to prove the incidence of recent tectonics, we must find unequivocal deformation marks on the geomorphologic surfaces and on the Pleistocene deposits. Moreover, the deformed surfaces/deposits must be dated. This poses several difficulties as the marine deposits could not be dated by TL and OSL is quite problematic due to the small thickness of the beds and its iron cemented character. In order to overcome these issues, the study of Quaternary sedimentary deposits of the coastal zone of Porto was based upon a very detailed fieldwork and the accurate altitude definition with a GPS (Leica SR20). The use of a static reference to correct the data obtained with the mobile receptor (rover) allowed us to obtain a good precision on the altitude of significant geomorphologic points. This procedure allowed us to characterize the several marine platflorms along this coastline and perform sonic detailed profiles of rock outcrops emerging from sand beaches. Studying the geomorphologic development of present day platforms and its relationship with tidal levels, it was possible to identify some rare tiny platform remains standing above actual platforms (possible Flandrian) and also the more frequent and generally deposit bearing Eemien platform. This work suggests that the last interglacial marine deposits have suffered some tectonic disturbance as they appear at quite different altitudes along this coastal zone. Furthermore, its altitude accompanies the general trend of geomorphologic features: the higher coastal sectors generally bearing higher coastal deposits and higher fossil platforms.
Subject: Ciências da terra e ciências do ambiente
Earth and related Environmental sciences
URI: http://hdl.handle.net/10216/75351
Document Type: Artigo em Revista Científica Internacional
Rights: openAccess
License: https://creativecommons.org/licenses/by-nc/4.0/
Appears in Collections:FLUP - Artigo em Revista Científica Internacional

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