Person:
Rossi Nieto, Carlos

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First Name
Carlos
Last Name
Rossi Nieto
URI
https://hdl.handle.net/20.500.14352/75285
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Geológicas
Department
Mineralogía y Petrología
Area
Petrología y Geoquímica
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2007 - 200922010 - 20121
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Author: Martín Chivelet, Javier ×

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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 Nieto, 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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    Chronology of Termination II and the Last Interglacial Period in North Spain based on stable isotope records of stalagmites from Cueva del Cobre (Palencia)
    (Journal of iberian geology, 2007) Muñoz García, María Belén; Martín Chivelet, Javier; Rossi Nieto, Carlos; Ford, D.C.; Schwarcz, H.P.
    New insight into the timing and structure of the Last Interglacial Period (Eemian) was obtained through U-Th dating of four speleothems from Northern Spain and an analysis of their stable isotope records. The four stalagmites examined were collected from different levels of Cueva del Cobre, a cold high-mountain cave in the Cantabrian Ranges (N Spain), in which speleothem growth took place essentially during the warmer interestadials. Through 18 TIMS and ICPMS datings and 263 stable isotope analyses, the onset of the Eemian interglacial period was precisely dated at 150±2 ka, an age consistent with a few other palaeoclimatic records but notably younger than the age ascribed by the Milankovitch theory. We also date the Eemian–Weichselian transition (~115 ka)for the first time in the Iberian Peninsula. U-Th ages revealed a consistent anomaly at ~105-100 ka BP, which could be related to a drastic environmental change during the MIS-5c interestadial. This event would have caused the resetting of the U-Th system at the base of the stalagmites during a short time interval. In addition, we propose a new simple geochemical test to ensure the lack of disturbance of this type of samples for dating purposes.
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    The Blake geomagnetic excursion recorded in a radiometrically dated speleothem
    (Earth and Planetary Science Letters, 2012) Osete López, María Luisa; Martín Chivelet, Javier; Rossi Nieto, Carlos; Edwards, R. Lawrence; Egli, Ramon; Muñoz García, María Belén; Wang, Xianfeng; Pavón Carrasco, Francisco Javier; Heller, Friedrich
    One of the most important developments in geomagnetism has been the recognition of polarity excursions of the Earth’s magnetic field. Accurate timing of the excursions is a key point for under standing the geodynamo process and for magnetostratigraphic correlation. One of the best-known excursions is the Blake geomagnetic episode, which occurred during marine isotope stage MIS 5, but its morphology and age remain controversial. Here wes how, for the first time, the Blake excursion recorded in a stalagmite which was dated using the uranium-series dis equilibrium techniques. The characteristic remanent magnetisation is carried by fine-grained magnetite. The eventis documented by two reversed intervals (B1 and B2). The age of the eventis estimated to be between 116.5 ± 0.7 kyr BP and 112.0 ± 1.9 kyr BP, slightly younger (~3–4 kyr) than recent estimations from sedimentary records sated by astronomical tuning. Low values of relative palaeointensity during the Blake episode are estimated, but a relative maximum in the palaeofield in tensity coeval with the complete reversal during the B2 interval was observed. Duration of the Blake geomagnetic excursion is 4.5 kyr, two times lower than single excursions and slightly higher than the stimated diffusion time for the inner core (~3 kyr).