Controles paleoambientales en la formación de calcretas en islas volcánicas. Gran Canaria
- A.M. Alonso-Zarza 1
- Á. Rodríguez-Berriguete 1
- A. Martín-Pérez 2
- R. Martín-García 1
- I. Menendez 3
- J. Mangas 3
- A.I. Casado 1
-
1
Universidad Complutense de Madrid
info
- 2 Institute of Palaeontology ZRC SAZU
-
3
Universidad de Las Palmas de Gran Canaria
info
Universidad de Las Palmas de Gran Canaria
Las Palmas de Gran Canaria, España
ISSN: 1576-5172
Year of publication: 2021
Issue Title: X Congreso Geológico de España
Issue: 18
Pages: 136
Type: Article
More publications in: Geotemas (Madrid)
Abstract
Gran Canary Island contains a wide variety of calcretes, whose distribution and features reflect the palaeoenvironmental conditions of their formation. Four of the studied profiles are located in coastal areas of the eastern of the Island, whereas the fifth is in the northern area at about 240 m high. The profiles are multi-storey and composed of prismatic, massive, laminar, pisolithic, ooidal, sandy mudstones, sandy mudstones with rhizoliths and brecciated horizons. The main features are: lami- nated micrite either homogeneous or containing clastic grains, desiccated micrite, fine crystalline dolomite ooids, peloids, clays, alveolar septal structures and spherulites. The δ 13 C values vary between -3.26 and -9.18 ‰ VPDB and δ18O between +0.86 and -3.24 ‰ VPDB. 87 Sr/86 Sr ratios are between 0.707504 and 0.708860, indicating that aeolian dust was the main calcium supply. Calcretes formed by carbonate precipitation within the soil controlled by roots and associated microorganisms. Calcretes distribution and features were directly controlled by the different relief along the island, which determined climate and vege- tation variations as well as aeolian dust distribution. Aeolian dust was a critical as supplied Ca to be fixed in the soil and contributing to CO2 sequestration.