Cicloestratigrafía en torno al evento MPBE (Selandiense superior) en Zumaia (Gipuzkoa) con foraminíferos planctónicos y minerales de la arcilla

• Main Authors: MARTIN ARNAU, RAUL, Arenillas Sierra, Ignacio, Bauluz Lázaro, Blanca
• Format: Bachelor Thesis
• Language: Spanish
• Published: Universidad de Zaragoza 2017
• Subjects: Planktonic foraminifera
• Online Access: http://zaguan.unizar.es/record/63780

This work includes a quantitative study of planktonic foraminifera at the genus level and a semiquantitative study of clay minerals of the upper Selandian at the Zumaia section (Gipuzkoa). The objective is to analyze the paleoenvironmental and paleoclimatic evolution across the horizon corresponding to the hyperthermal event called Mid Paleocene Biotic Event (MPBE). For the planktonic foraminifera study, a total of 20 samples were analyzed which were prepared by the classic washing techniques. For the paleoclimatic reconstruction, the index C/F was used, which marks the proportion of tropical-subtropical genera. For the mineralogical analysis, 12 of these samples were studied by means of the X-ray diffraction technique of the total sample and the clay fraction (<2µm). The curves of the index C/F and clay mineral abundance indicate cyclical variations compatible with the Milankovitch cycles (of precession and eccentricity). The more marly beds exhibit a greater abundance of tropical-subtropical genera and chlorites, suggesting warmer periods of insolation maximum. The horizon of the MPBE represents an absolute maximum in the index C/F, but does not reflect a significant event different from the rest of the marly levels within the precession cycles identified at Zumaia.