Quaternary Glacial Geology of Alta Ribagorqa Basin (Central Southern Pyrenees)

This paper is an abstract of the doctoral thesis presented by the autor at the University of Barcelona on September 1983. It constitutes a regional study about the Quatemary Glacial Geology in the Ribagorca high valleys. It is the first work in relation to the geomorphology, sedimentology and stratigraphy of the glacial and related deposits in this zone of the Pyrenees. Several formations of quatemary deposits have been studied in detail (mainly in Llauset Valley and in Tall area); and the local quatemary stratigraphy is established and finally a correlation with some previously studied areas in the Pyrenees is attemped.

Preliminary integrated magnetostratigraphic and biostratigraphic correlation in the Miocene Lorca Basin (Murcia, SE Spain).

The Lorca basin is one of the Neogene basins OS South Eastern Spain. The infilling Tortonian-Messinian deposits are mainly composed OS marls and reach up to 1,200 m in thickness. A biostratigraphic survey OS these deposits, assisted by the determination OS the magnetic polarity reversal pattern Sor most OS these deposits (900 m), has enabled the Tortonian-Messinian chronostratigraphy to be precised. The close sampling space for biostratigraphic determination has enabled the accurate location OS Sour main biostratigraphic events than can be correlated with charactenstic events of the Mediterranean biostratigraphic Zones. In addition, the location OS the TortonianNessinian boundary has been accurately placed at some 150 m below the main gypsurn unit outcropping in the basin. The integrated bio-magnetostratigraphic data fiom the studied section allows a tentative interpretation OS the identified magnetozones. Thus, a correlation to the Geomagnetic Polarity Time Scale is presented for more than 900 m of pre-evaporite Miocene stratigraphic succession fiom the Lorca basin. Moreover, about 15' OS anticlockwise rotation has been detected. Its significance is evaluated in the basin geodynamic framework.

Tectonic-palaeoenvironmental forcing of clay-mineral assemblages in nonmarine settings: the Oligocene-Miocene As Pontes Basin (Spain)

Two small, alluvial-lacustrine subbasins developed during the early restraining overstep stages of the Oligocene-Miocene As Pontes strike-slip Basin (NW Spain). Later, the basin evolved into a restraining bend stage and an alluvial-swamp-dominated depositional framework developed. The palaeobiological record demonstrates that the Oligocene-Miocene palaeoclimate in NW Spain was subtropical, warm and humid to subhumid.

Analysis of resuspension and sedimentation processes of unaltered fish faeces using image analysis

Postprint (published version)

The age of the"Grande Coupure" mammal turnover: New constraints from the Eocene Oligocene record of the Eastern Ebro Basin (NE Spain.)

The Grande Coupure represents a major terrestrial faunal turnover recorded in Eurasia associated with the overall climate shift at the Eocene-Oligocene transition. During this event, a large number of European Eocene endemic mammals became extinct and new Asian immigrants appeared. The absolute age of the Grande Coupure, however, has remained controversial for decades. The Late Eocene-Oligocene continental record of the Eastern Ebro Basin (NE Spain) constitutes a unique opportunity to build a robust magnetostratigraphy- based chronostratigraphy which can contribute with independent age constraints for this important turnover. This study presents new magnetostratigraphic data of a 495-m-thick section (Moià-Santpedor) that ranges from 36.1 Ma to 33.3 Ma. The integration of the new results with previous litho- bio- and magnetostratigraphic records of the Ebro Basin yields accurate ages for the immediately pre- and post-Grand Coupure mammal fossil assemblages found in the study area, bracketing the Grande Coupure to an age embracing the Eocene-Oligocene transition, with a maximum allowable lag of 0.5 Myr with respect to this boundary. The shift to drier conditions that accompanied the global cooling at the Eocene-Oligocene transition probably determined the sedimentary trends in the Eastern Ebro Basin. The occurrence and expansion of an amalgamated-channel sandstone unit is interpreted as the forced response of the fluvial fan system to the transient retraction of the central-basin lake systems. The new results from the Ebro Basin allow us to revisit correlations for the controversial Eocene-Oligocene record of the Hampshire Basin (Isle of Wight, UK), and their implications for the calibration of the Mammal Palaeogene reference levels MP18 to MP21.

20 Myr of eccentricity paced lacustrine cycles in the Cenozoic Ebro Basin

Long-period orbital forcing is a crucial component of the major global climate shifts during the Cenozoic as revealed in marine pelagic records. A complementary regional perspective of climate change can be assessed from internally drained lake basins, which are directly affected by insolation and precipitation balance. The Ebro Basin in northeastern Iberia embraces a 20 Myr long continuous sedimentary record where recurrent expansions and retractions of the central lacustrine system suggest periodic shifts of water balance due to orbital oscillations. In order to test climatic (orbital) forcing a key-piece of the basin, the Los Monegros lacustrine system, has been analyzed in detail. The cyclostratigraphic analysis points to orbital eccentricity as pacemaker of short to long-term lacustrine sequences, and reveals a correlation of maxima of the 100-kyr, 400-kyr and 2.4-Myr eccentricity cycles with periods of lake expansion. A magnetostratigraphy-based chronostratigraphy of the complete continental record allows further assessing long-period orbital forcing at basin scale, a view that challenges alternate scenarios where the stratigraphic architecture in foreland systems is preferably associated to tectonic processes. We conclude that while the location of lacustrine depocenters reacted to the long-term tectonic-driven accommodation changes, shorter wavelenght oscillations of lake environments, still million-year scale, claims for a dominance of orbital forcing. We suggest a decoupling between (tectonic) supply-driven clastic sequences fed from basin margins and (climatic) base level-driven lacustrine sequences in active settings with medium to large sediment transfer systems.

Modelling syntectonic sedimentation: combining a discrete element model of tectonic. Deformation and process-based sedimentary Model in 3D.

This paper presents a new numerical program able to model syntectonic sedimentation. The new model combines a discrete element model of the tectonic deformation of a sedimentary cover and a process-based model of sedimentation in a single framework. The integration of these two methods allows us to include the simulation of both sedimentation and deformation processes in a single and more effective model. The paper describes briefly the antecedents of the program, Simsafadim-Clastic and a discrete element model, in order to introduce the methodology used to merge both programs to create the new code. To illustrate the operation and application of the program, analysis of the evolution of syntectonic geometries in an extensional environment and also associated with thrust fault propagation is undertaken. Using the new code, much more complex and realistic depositional structures can be simulated together with a more complex analysis of the evolution of the deformation within the sedimentary cover, which is seen to be affected by the presence of the new syntectonic sediments.

Impacts of climate change on water resources in the Mediterranean basin : a case study in Catalonia, Spain

Most climate change projections show important decreases in water availability in the Mediterranean region by the end of this century. We assess those main climate change impacts on water resources in three medium-sized catchments with varying climatic conditions in north-eastern Spain. A combination of hydrological modelling and climate projections with B1 and A2 IPCC emission scenarios is performed to infer future stream flows. The largest reduction (22-48% for 2076-2100) of stream flows is expected in the headwaters of the two wettest catchments, while lower decreases (22-32% for 2076-2100) are expected in the drier one. In all three catchments, autumn and summer are the seasons with the most notable projected decreases in stream flow, 50% and 34%, respectively (2076-2100). Thus, ecological flows might be noticeably impacted by climate change in the catchments, especially in the headwaters of those wet catchments.