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Contourites, as deposits from thermohialine-induced geostrophic bottom currents, provide essential paleoenvironmental (i.e., ecological, depositional) information, especially on ocean circulation and climate change. Furthermore, the economic interest in contourite deposits has increased significantly during the last decades, being considered an important unconventional reservoir in hydrocarbon exploration. All of this determines the important advance in the knowledge of this facies, and in its application in paleoclimatology and paleoceanography research as well as in petroleum exploration. However, the recognition and characterization of ancient contourite deposits are not always an easy matter, being in most of the cases difficult to discriminate from other deep-sea facies (i.e., pelagites/hemipelagites, turbidites). Recently, ichnological approach has been revealed as a very useful tool in contourite research. On this base, this PhD Thesis focus on the ichnological analysis of ancient contourite outcrops, to advance in the characterization and differentiation of this facies, its use for palaeoenvironmental reconstructions, and its interest in reservoir characterization. With this purpose two main ancient contourite drift successions were selected: a) Late Miocene channelized clastic contourite deposits at Morocco and, b) Eocene-Miocene calcareous contourite drift deposits at Cyprus. Obtained ichnological information, including ichnofabrics and ichnofacies, allows characterization of different types of contourites, as well as its differentiation respect to hemipelagites and turbidites. In general contourites are usually characterized by high trace fossil abundance and low ichnodiversity, but significant differences occurs respect to the particular type. Specific palaeoenvironmental conditions during contourite deposition have been interpreted, showing that bottom currents played an important role on deep-sea macrobenthic community, specially providing a high nutrient supply to the seafloor. The bioturbation´s influence on petrophysical properties (i.e., porosity) of contourite deposits is also demonstrated, as exemplified with Macaronichnus trace fossil. Characterization of ichnological attributes may be a key factor for evaluating the real potential of these unconventional reservoirs. All these advances prove the usefulness of ichnology in the study of ancient contourites, supporting the ichnological approach as a tool in palaeoenvironmental, sedimentological and reservoir characterization of contourite facies., Las contornitas, entendidas como depósitos de corrientes geostróficas de fondo termohalinamente inducidas, proporcionan información paleoambiental esencial (ecológica, deposicional), especialmente sobre la circulación oceánica y el cambio climático. Además, el interés económico por los depósitos contorníticos se ha incrementado significativamente durante las últimas décadas, siendo considerado un importante reservorio (no convencional) en la exploración de hidrocarburos. Todo ello ha conllevado un importante avance en el conocimiento de estas facies, y en su aplicación en la investigación paleoclimatológica y paleoceanográfica, así como en la exploración petrolera. Sin embargo, el reconocimiento y caracterización de antiguos depósitos contorníticos no siempre es fácil, siendo en la mayoría de los casos difícil de diferenciar frente a otras facies marino profundas (pelagitas / hemipelagitas y turbiditas). Recientemente, el análisis icnológico se ha manifestado como una herramienta muy útil en la investigación de las contornitas. Sobre esta base, la presente Tesis Doctoral se centra en el análisis icnológico de afloramientos contorníticos con el fin de avanzar en: la caracterización y diferenciación de estas facies, su uso para reconstrucciones paleoambientales y su interés en la caracterización de reservorios. Con este propósito, se seleccionaron dos ejemplos contorníticos: a) depósitos de canales contorníticos clásticos del Mioceno Superior en Marruecos y, b) depósitos contorníticos calcáreos del Eoceno-Mioceno en Chipre. La información icnológica obtenida, incluyendo las icnofábricas e icnofacies, permite caracterizar los diferentes tipos de contornitas, así como su diferenciación respecto a hemipelagitas y turbiditas. En general, las contornitas se caracterizan por una alta abundancia de trazas de fósiles y una baja icnodiversidad, pero se reconocen diferencias significativas con respecto al tipo de contornita. Se han interpretado condiciones paleoambientales específicas durante el depósito de las contornitas, lo que demuestra que las corrientes de fondo desempeñaron un papel importante sobre la comunidad macrobentónica de aguas profundas, proporcionando altas cantidades de nutrientes al fondo marino. También se ha demostrado la influencia de la bioturbación en las propiedades petrofísicas (porosidad) de los depósitos contorníticos, como se ejemplifica con la traza fósil Macaronichnus. La caracterización de aspectos icnológicos puede ser un factor clave para evaluar el potencial real de estos reservorios no convencionales. Todos estos avances demuestran la utilidad de la icnología en el estudio de contornitas, apoyando el enfoque icnológico como herramienta en la caracterización paleoambiental, sedimentológica y petrolífera de facies contorníticas., Tesis Univ. Granada., Ministerio de Educación y Formación Profesional de España. Contrato de Formación de Profesorado Universitario (FPU16/01173), Secretaría de Estado en I+D+i del Ministerio de Economía y Competitividad del Gobierno de España, en el marco de los Proyectos CGL2015-66835-P y PID2019- 104625RB-100, Consejería de Economía, Innovación, Ciencia y Empleo de la Junta de Andalucía mediante los proyectos RNM-3715, P18-RT-4074 y el Grupo de Investigación RNM- 178, Ministerio de Educación y Formación Profesional de España. Ayudas a la movilidad para estancias breves y traslados temporales (EST 18/00598; EST19/00248), Ministry of Science and Technology of Taiwan (MOST), which provided a scholarship to conduct an internship at the National Taiwan University, Taipei, Taiwan (2018)

At present, the Southern Ocean plays an important role in the global climate system and in modern Antarctic ice sheet dynamics. Past Southern Ocean configurations are however poorly understood. This information is yet important as it may provide important insights into the climate system and past ice-sheet behavior under warmer than present day climates. Here we study Southern Ocean dynamics during the Oligocene and Miocene when reconstructed atmospheric CO concentrations were similar to those expected during this century. We reconstruct snapshots of late Oligocene to earliest Miocene (~24.2–23 Ma) paleoceanographic conditions in the East Antarctic Wilkes Land abyssal plain. For this, we combine marine sedimentological, geochemical (X-ray fluorescence, TEX,), palynological and isotopic (ε) records from ocean sediments recovered at Deep Sea Drilling Project (DSDP) Site 269. Overall, we find that sediments, delivered to the site by gravity flows and hemipelagic settling during glacial-interglacial cycles, were persistently reworked by a proto-Circumpolar Deep Water (CDW) with varying strengths that result from climatically controlled frontal system migrations. Just prior to 24 Ma, terrigenous input of predominantly fine-grained sediments deposited under weak proto-CDW intensities and poorly ventilated bottom conditions dominates. In comparison, 24 Ma marks the start of episodic events of enhanced proto-CDW current velocities, associated with coarse-grained deposits and better-ventilated bottom conditions. In particular, the dominance of P-cyst and low Calcium (Ca) in the sediments between ~ 24.2 Ma and 23.6 Ma indicate the presence of an active open ocean upwelling associated with high nutrient conditions. This is supported by TEX-derived sea surface temperature (SST) data pointing to cool ocean conditions. From ~ 23.6 to 23.2 Ma, our records reveal an enrichment of Ca in the sediments related to increased calcareous microfossil preservation, high amounts of G-cysts and increasing TEX-SSTs. This implies warmer water masses reaching the Antarctic margin as the polar front migrated southward. Together with the radiogenic Nd isotope data indicating modern-like CDW values, our records suggest a prominent poleward expansion of proto-CDW over our study site and reduced AABW formation during the latest Oligocene (i.e. ~23.2 Ma ago). Our findings support the notion of a fundamentally different Southern Ocean, with a weaker proto-ACC than present during the late Oligocene and the earliest Miocene., This research used samples provided by the International Ocean Discovery Program (IODP). We thank the staff at the Gulf Coast core repository (GCR) for assistance in core handling and shipping. We also thank David Houpt (GCR) for technical support with the XRF core scanning; Katharina Kreissig, Liam Holder, Barry Coles (Imperial College) and Katrina Kerr (Open University) for laboratory and technical support with the Nd isotopes and REE analyses; Emmanuelle Ducassou, Marie-Claire Perello (EPOC) for laboratory and technical support with the grain-size analyses and Hans Nelson for his helpful discussions and improvement of the English in the manuscript. We also thank Laura De Santis and an anonymous reviewer for their constructive comments, which helped to improve this paper. Funding for this research was provided by the Onassis Foundation – Scholarship ID: F ZL 016-1/2015-2016 and the Spanish Ministry of Science and Innovation (grant CTM2017-89711-C2-1-P), co-funded by the European Union through FEDER funds. PB and FH acknowledge funding through the NWO polar programme grant no ALWPP.2016.001 and the European Research Council starting grant no 802835, OceaNice. This paper is a contribution to the SCAR PAIS Programme.