Person: Rodríguez Berriguete, Álvaro
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First Name
Álvaro
Last Name
Rodríguez Berriguete
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Geológicas
Department
Mineralogía y Petrología
Area
Petrología y Geoquímica
Identifiers
7 results
Search Results
Now showing 1 - 7 of 7
Item El centro de interpretación de la Cueva de Castañar: un ejemplo de difusión de la investigación en Geología Sedimentaria(2011) Martín Pérez, A.; Alonso Zarza, Ana María; Martín García, Rebeca; Gil Peña, I.; Meléndez, A.; Herrero Fernández, María Josefa; Rodríguez Berriguete, Álvaro; Pérez-Monserrat, Elena M.; Charco Romero, MaríaItem Tobas carbonáticas como resultado del riego con aguas subterráneas ricas en CO2 de origen volcánico(Enseñanza de las ciencias de la tierra, 2019) Rodríguez Berriguete, Álvaro; Alonso Zarza, Ana María; Martín García, Rebeca; Cabrera, Mª CarmenItem Gypsum speleothems in lava tubes from Lanzarote (Canary Islands). Ion sources and pathways(Sedimentary Geology, 2019) Huerta, Pedro; Martín Pérez, Andrea; Martín García, Rebeca; Rodríguez Berriguete, Álvaro; La Iglesia, Á.; Alonso Zarza, Ana MaríaLava tubes from Lanzarote Island in the Canary Archipelago commonly show white speleothems that stand out from the black basaltic rock. Mineralogical analyses of the speleothems from El Covón and Chifletera lava tubes show that gypsum is the dominant mineral with minor amounts of halite. Speleothems composed of microcrystalline gypsum (up to 150 μm long) are: coatings, globules, or extensive white powder accumulations covering the tube floor. Those composed of macrocrystalline gypsum with millimetric-size tabular and lenticular crystals are: crusts and stalactites. Uranium series dating of speleothems show ages ranging from 6217 ± 1644 yr to 40,039 ± 4748 yr. δ34S and the δ18O of gypsum speleothems (δ34S is 20.97‰ V-CDT and δ18O is 9.78‰ V-SMOW) is similar to that of sulphate dissolved in seawater. 87Sr/86Sr from speleothems (0.708665–0.708976) suggests that the main source of Ca is seawater, but additional Ca contributions from aeolian dust have reduced the Sr isotope values. These data support the idea that gypsum precipitates in the lava tube by evaporation of marine spray or solutions derived from marine spray. Two probable vias for ions input into the lava tube are considered: 1) sea spray circulating through the lava tube; 2) low-frequency rain infiltration leaching the marine spray salts precipitated at the surface. The constant supply of ions from sea spray, air currents in the cave, and the fast, but partial, evaporation due to the high relative humidity in the lava tube favours accumulation of major amounts of gypsum and subordinately halite. Scarcity of precipitation in the western Canary Islands prevents dissolution of gypsum speleothems.Item Diagenesis of continental carbonate country rocks underlying surficial travertine spring deposits(Quaternary International, 2017) Rodríguez Berriguete, Álvaro; Alonso Zarza, Ana María; Martín García, RebecaDiagenesis of Miocene-Pliocene continental rocks in extensional Teruel Basin related to deposition of a travertine at surface has been studied. Most of the diagenetic processes described here are in relation tothe travertine deposition, so they are not widespread along the basin. Due to their high induration degreethese rocks may be misinterpreted with travertine/tufa facies, so there is a need of clear criteria for their recognition as they can supply important hydrological and paleoenvironmental information. The diagenetic processes, that deeply modified the substrate, include dissolution, recrystallization and cementation and lead to a high induration of the Miocene-Pliocene rocks. These processes were driven by groundwater flow leading to travertine deposition at surface and appeared to be closely related to the fluvial incision of Alfambra River and to extensional fracturation during Middle Pleistocene times probably under humid conditions. The cementation sequences and the organization of fractures and vadose micrite point to alternating vadose-phreatic conditions and syndiagenetic movements of the faults. Isotopic signal show lighter d18O than that of the unaltered Miocene-Pliocene rocks and similar d13C, suggesting lighter oxygen signal in waters during interglacial Pleistocene periods, and a common origin for carbon from marine Mesozoic rocks from the substrate of the basin. All of that suggest the strong control of tectonics, and climate at different timescales in diagenesis of the rocks serving as substrate for surficial travertine deposition.Item Effect of aragonite to calcite transformation on the geochemistry and dating accuracy of speleothems. An example from Castañar Cave, Spain(Sedimentary Geology, 2019) Martín García, Rebeca; Alonso Zarza, Ana María; Frisia, Silvia; Rodríguez Berriguete, Álvaro; Drysdale, Russell; Hellstromf, JohnAragonite speleothems are increasingly being used as high-resolution climate proxies; however, aragonite is unstable and susceptible to diagenetic transformation into calcite leading to mineralogical, textural and geochemical alterations that have not been fully investigated. To provide some insights to these modifications, this study combines stable isotope geochemistry and U-series dating with petrological observations and EMPA elemental analyses to characterize a stalagmite from Castañar Cave (Cáceres, Spain) that shows primary aragonite diagenetically altered and with reverse ages. The diagenetic processes include recrystallization to calcite, micritization and dissolution. Characterization and interpretation of the chemistry and nature of the waters from which the aragonite precipitated, and of the ones that subsequently formed the calcite, indicates that both polymorphs formed from the same fluids. These fluids hydrochemically evolved from an “aragonite mode” to a “calcite mode” along a diagenetic path within the sample. The results show that during transformation the system stayed close in one of the stages, and open in the other with the same textural result. Reverse ages are found either in the recrystallized areas or in the primary aragonite, caused by two different U-remobilization mechanisms, U-leaching due to flowing waters on the surface, and U-loss during the transformation process. These results highlight the complex behavior of speleothems during diagenesis and the impact on the geochemical information of the primary and secondary phases, and thus the importance of petrological and geochemical characterization of speleothems for paleoclimatic studies.Item Unravelling calcrete environmental controls in volcanic islands, Gran Canaria Island, Spain(Palaeogeography, Palaeoclimatology, Palaeoecology, 2020) Alonso Zarza, Ana María; Rodríguez Berriguete, Álvaro; Martín Pérez, Andrea; Martín García, Rebeca; Menéndez, Inmaculada; Mangas, JoséVolcanic islands are unique contexts to analyze the controls on calcrete development in settings with varied relief, climate and vegetation, and lacking carbonate host rocks. This paper discusses the formation of Quaternary calcrete profiles in Gran Canaria volcanic Island, under direct influence of the SAL (Saharian Air Layer). Calcrete profiles are multi-storey and composed of prismatic, massive, laminar, pisolithic, ooid-bearing, sandy mudstones with rhizoliths and brecciated horizons. Host rocks include basalts, siliceous mudstones, volcanic sands and gravels and bioclastic-rich sands. Carbonate is mostly calcite but some dolomite occurs in massive horizons. The main microfabrics include laminated micrite, fine crystalline dolomite, desiccated micrite, micrite-clay groundmass, oriented Mg-rich clays, peloids, spherulites and coated grains. δ13C varies from −3.26 to −9.18‰ VPDB and δ18O from +0.86 to −3.24‰ VPDB. The 87Sr/86Sr ratios are between 0.707504 and 0.708860, indicating that calcium was mostly supplied from the CaCO3-rich aeolian dust coming from the Sahara Desert. Calcrete profiles are mostly pedogenic with roots and microorganisms enabling carbonate precipitation within the soils. The correlation trend of δ13C and δ18O points to a climate control on precipitation, with the heavier isotope values in the horizons containing dolomite. Sedimentation rates interplayed with calcrete formation processes and erosion to outline the profiles/horizons. Amalgamated laminar horizons formed when the rate of calcrete formation was higher than sedimentation and erosion, whereas areas or periods with relatively higher sedimentation allowed the separation of calcrete horizons. The direction of the winds supplying aeolian dust, and the varied relief, vegetation and climate favored better development of calcretes in the relatively arid and lowland areas of the eastern side of the island. Our study shows that calcretes contain the record of the paleoenvironmental controls that operated in volcanic islands with no previous carbonate substrates.Item The role of climate and aeolian dust input in calcrete formation in volcanic islands (Lanzarote and Fuerteventura, Spain)(Palaeogeography, Palaeoclimatology, Palaeoecology, 2015) Huerta, Pedro; Rodríguez Berriguete, Álvaro; Martín García, Rebeca; Martín Pérez, Andrea; La Iglesia Fernández, Ángel; Alonso Zarza, Ana MaríaCalcretes are widely described in non-marine settings with carbonates in their catchment, or vicinity areas, but in volcanic islands without carbonates in their substrate, calcretes are not very common. In Lanzarote and Fuerteventura Canary Islands, characterized by impressive volcanic landscapes, the sedimentary carbonate rocks are rare except for some recent marine and aeolian deposits. In these settings very well-developed calcretes cover large areas of the present landscape. The source of calcium required for the formation of these calcretes has not been discussed in much detail till now, although its role is critical to an understanding of the climatic conditions in which calcium was transported and fixed and of the calcrete formation processes. The petrological and geochemical studies (87Sr/86Sr ratios, δ13C, δ18O, major, trace and REE) carried out in this paper do confirm the important role of aeolian dust input in the formation of these calcretes. Canarian calcretes were mainly generated by pedogenic processes and are composed of various irregular carbonate lamina interbedded with fine clastic deposits. Our study indicates that these interbeddings were the result of several stages in which, during dry periods, aeolian dust deposition alternated with leaching and calcite precipitation during wetter periods when plants, insects and bacteria played an important role in carbonate precipitation. The δ18O (− 2.70 to + 2.22‰ VPDB) and δ13C (− 8.21 to + 0.24‰ VPDB) values indicate that calcretes were formed by pedogenic processes. Comparison of calculated ∆18O values for the Canary calcretes with continental mid-latitude calcrete values reflects the more homogeneous temperature regimes of calcrete formation in island (oceanic) settings. Calcrete87Sr/86Sr ratios (0.706357 to 0.709208) show strong affinity with those obtained in aeolian carbonate dust and marine deposits, and are relatively different from those obtained in basalts. REE, major and trace element concentrations show that Ca-bearing minerals from volcanic host rock contributed little to calcrete formation and most of the calcium was supplied by aeolian deposits such as the aeolian dust coming from the Sahara and Sahel or sand dunes.