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Bravo, A. M.
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Bravo, A. M.
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- PublicationRestrictedIntegrated stratigraphy from the Vallcebre Basin (southeastern Pyrenees, Spain): new insights on the continental Cretaceous-Tertiary transition in southwest Europe(2007)
; ; ; ; ; ; ; ;Oms, O.; Universitat Autònoma de Barcelona, Facultat de Ciències (Geologia), E-08193 Bellaterra, Barcelona, Spain ;Dinarès-Turell, J.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Vicens, S.; Universitat Autònoma de Barcelona, Facultat de Ciències (Geologia), E-08193 Bellaterra, Barcelona, Spain ;Estrada, R.; Universitat Autònoma de Barcelona, Facultat de Ciències (Geologia), E-08193 Bellaterra, Barcelona, Spain ;Vila, B.; Institut Català de Paleontologia C/ Escola Industrial, 23, E-08201 Sabadell, Barcelona, Spain ;Galobart, À.; Institut Català de Paleontologia C/ Escola Industrial, 23, E-08201 Sabadell, Barcelona, Spain ;Bravo, A. M.; Unidad de Paleontología, Departamento de Biología, Universidad Autónoma de Madrid, E-28049 Cantoblanco, Madrid, Spain; ; ; ; ; ; An integrated sedimentological, magnetostratigraphic, and paleontological study of the Vallcebre section (south eastern Pyrenees, Spain) is carried out in order to define and portray the transition from the Cretaceous to the Tertiary in a continental setting. A robust magnetostratigraphy is correlated to the standard polarity scale in light of known biochronological constraints (charophyte, marine invertebrates, eggshells and other dinosaur remains). Our results show that this section is among the thickest stratigraphic records for the continental Maastrichtian in the Old World. Sedimentology indicates a progressive regression from marine through lagoonal to entirely continental environments. The section is dominated by mudstones deposited under low energy conditions. Exceptionally, a basin-wide regression maximum is recorded some time before the Cretaceous–Tertiary boundary (K/T). This regression maximum is marked by the input of coarse-grained (alluvial) sediments that record a dramatic change in the landscape (quiet mud plains changed to sandy floodplains deposited by high-energy currents). After a period of renewed quiescence following the regression maximum, a Cenozoic flooding took place. Such terminal Cretaceous sequence of events has been recorded in shorter sections in several other basins from southwestern Europe. This energetic sediment input suggests that some time before the K/T event, a sudden paleoenvironmental reorganization took place in the continental basins of south western Europe.143 24 - PublicationOpen AccessIonospheric response modeling under eclipse conditions: Evaluation of 14 December 2020, total solar eclipse prediction over the South American sector(2022)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;In this work, we evaluate the SUPIM-INPE model prediction of the 14 December 2020, total solar eclipse over the South American continent. We compare the predictions with data from multiple instruments for monitoring the ionosphere and with different obscuration percentages (i.e., Jicamarca, 12.0°S, 76.8°W, 17%; Tucumán 26.9°S, 65.4° W, 49%; Chillán 36.6°S, 72.0°W; and Bahía Blanca, 38.7°S, 62.3°W, reach 95% obscuration) due to the eclipse. The analysis is done under total eclipse conditions and non-total eclipse conditions. Results obtained suggest that the model was able to reproduce with high accuracy both the daily variation and the eclipse impacts of E and F1 layers in the majority of the stations evaluated (except in Jicamarca station). The comparison at the F2 layer indicates small differences (<7.8%) between the predictions and observations at all stations during the eclipse periods. Additionally, statistical metrics reinforce the conclusion of a good performance of the model. Predicted and calibrated Total Electron Content (TEC, using 3 different techniques) are also compared. Results show that, although none of the selected TEC calibration methods have a good agreement with the SUPIM-INPE prediction, they exhibit similar trends in most of the cases. We also analyze data from the Jicamarca Incoherent Scatter Radar (ISR), and Swarm-A and GOLD missions. The electron temperature changes observed in ISR and Swarm-A are underestimated by the prediction. Also, important changes in the O/N2 ratio due to the eclipse, have been observed with GOLD mission data. Thus, future versions of the SUPIM-INPE model for eclipse conditions should consider effects on thermospheric winds and changes in composition, specifically in the O/N2 ratio.45 36