Person:
Muñoz García, María Belén

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First Name
María Belén
Last Name
Muñoz García
URI
https://hdl.handle.net/20.500.14352/75243
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Geológicas
Department
Geodinámica, Estratigrafía y Paleontología
Area
Estratigrafía
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2008 - 200912010 - 20172
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    Comparison of speleothem fabrics and microstratigraphic stacking patterns in calcite stalagmites as indicators of paleoenvironmental change
    (Quaternary International, 2016) Muñoz García, María Belén; Cruz, J.; Martín Chivelet, Javier; Ortega, Ana Isabel; Turrero, M.J.; López Elorza, M.
    In the necessary task of obtaining high-resolution paleoclimate series from speleothems, the characterization of their internal microstratigraphy is a useful tool for: a) improving geochronology, and b) reaching a more complete knowledge of the speleothem formation and evolution through time and thus obtaining additional paleoenvironmental information. However, the development of standardized methodologies for microstratigraphic characterization is a pending task. In this paper, two different approaches allow construction of microstratigraphic logs for three stalagmites retrieved from two different caves. The logs correspond to vertical variations in speleothem fabrics and in microstratigraphic stacking patterns. The “fabrics logs” essentially provide information about the drip rate (sometimes used as a precipitation proxy) and the regularity or irregularity of each drip in the short-term. The “microstratigraphic stacking patterns logs” can be interpreted to obtain information about the changes in drip rates in the mid- and long-term. The results show a broad correlation between both kinds of logs that supports their validity as paleoenvironmental proxies. Fabrics formed under relatively constant and regular drips (columnar compact, open and elongated) usually constitute aggradational or progradational microstratigraphic stacking patterns. On the other hand, retractional stacking patterns are usually related with fabrics precipitated under more irregular drips (dendritic and columnar microcrystalline).However, this relation is not rigid and the information obtained from the logs is not equivalent, but complementary. The combination of both logs allows reconstruction of the hydrological history for each drip site. As all the obtained information derives directly from the drip conditions, drip effects result to be very important and can, in some cases, overwhelm the paleoclimate information recorded in each stalagmite.
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    Comparación del clima interglacial eemiense y holoceno en el norte de España a partir de los indicadores paleoclimáticos de estalagmitas de la Cueva del Cobre (Palencia)
    (Geotemas, 2008) Muñoz García, María Belén; Martín Chivelet, Javier; Rossi, Carlos; Ford, D.C.; Schwarez, H.P.
    El Eemiense se suele considerar un buen análogo del Holoceno a pesar de la diferente configuración orbital de cada época. La comparación de varios indicadores paleoclimáticos obtenidos en estalagmitas eemienses y holocenas de la Cueva del Cobre (Montaña Palentina) aporta datos que permiten verificar esta supuesta similitud. Los indicadores paleoclimáticos comparados son la tasa de crecimiento de las estalagmitas, las texturas de la calcita y los isótopos estables de oxígeno. En comparación con los holocenos, los espeleotemas eemienses son más grandes porque han crecido sin interrupción durante más tiempo, presentan una variedad menor de texturas de calcita y apenas registran láminas anuales. Además, ni las texturas de calcita ni la composición isotópica de oxígeno muestran signos de alteración diagenética. En función de estos indicadores se ha podido deducir que el clima de la zona de estudio fue durante el Eemiense ligeramente más cálido que durante el Holoceno y considerablemente más seco, contradiciendo las estimaciones más aceptadas del clima global para el Último Periodo Interglacial. El clima eemiense en la zona de estudio fue además más estable y tuvo una estacionalidad menos marcada que en los últimos 6000 años. El análisis de los cambios sincrónicos de estos indicadores ha permitido estimar una duración del Último Periodo Interglacial de ~21ka en esta zona.
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    Speleothem architectural analysis: integrated approach for stalagmite-based paleoclimate research
    (Sedimentary Geology, 2017) Martín Chivelet, Javier; Muñoz García, María Belén; Cruz, Juncal A.; Ortega Martínez, Ana Isabel; Turrero Jiménez, María Jesús
    Carbonate stalagmites have become increasingly attractive to Quaternary paleoclimate research, as they can be accurately dated by radiometric methods and concurrently yield high-resolution multi-proxy records of past climate conditions. Reliable series however require the precise characterization of stalagmite internal icrostratigraphy,4 a task too often poorly accomplished despite the recent advances in speleothem research. This weakness is due to the lack of a robust integrative methodological framework capable of integrating the wide range of petrographical and micro-stratigrafical methods currently used in speleothem characterization. For covering this need, this review introduces the Speleothem Architectural Analysis (SAA), a holistic approach inspired in well-established stratigraphic procedures such as the architectural element analysis and the sequence stratigraphy, commonly used by geoscientists for categorizing internal stratigraphic heterogeneities in sedimentary deposits. The new approach establishes a six-fold hierarchy of speleothem architectural elements and their bounding surfaces: individual crystallites (1st order), single growth layers (2nd order), speleothem fabrics (3rd order), stacking patterns sets (4th order), morphostratigraphic units (5th order), unconformity-bounded units and major unconformities (6th order). Each category of architectural element is formed in a different range of time, from intervals as short as a year/season to others of centuries or millennia. The SAA, which has the capability of incorporating any petrographic or stratigraphic classification, provides a useful, systematic, and versatile tool for unraveling the complexities of speleothem growth, and thus for genetically interpreting stalagmites in a multi-temporal scale. A detailed speleothem stratigraphy must be the basis for performing robust reconstruction of paleoclimate series. They should precede and accompany any work focused in absolute age dating or in reconstructing paleoclimate by means of any geochemical proxy