Formation, exposure, and evolution of a high-latitude beachrock in the intertidal zone of the Corrubedo complex (Ria de Arousa, Galicia, NW Spain)
✍ Scribed by D Rey; B Rubio; A.M Bernabeu; F Vilas
- Publisher
- Elsevier Science
- Year
- 2004
- Tongue
- English
- Weight
- 923 KB
- Volume
- 169
- Category
- Article
- ISSN
- 0037-0738
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✦ Synopsis
The presence of beachrocks is noted on the Galician shoreline at 41jN, a latitude at which this phenomenon is rarely found. The present study focuses on the petrological characterization and sedimentological evolution of a beachrock that was exhumed during an exceptional storm in the winter of 2001 in the intertidal zone of a high-energy beach. The cemented material comprises medium-to-coarse mixed siliciclastic-carbonate sands. Unlike tropical beachrocks, the cement consists of epitaxial low-Mg calcite presenting varied morphologies and textures: acicular and bladed coatings and pore linings, pore fillings of sparitic calcite, and meniscus-style cements. Seawater, dominantly wave action, plus marine and meteoric mixed waters are invoked as the main generative fluids. Beachrock formation and evolution are approached from a morphodynamic viewpoint, considering four progressive stages:
- initial cementation in the intertidal zone; 2. exposure and modelling by wave action; 3. colonization and hardening; and 4. disintegration/preservation and burial.
Finally, the morphodynamic significance, climatic implications, and occurrence of this type of cementation along the north and northwest shoreline of Spain are discussed.