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The Cordovilla basin, located within the frontal thrust belt of the Betic Cordillera, SE Spain, is an elongated NW–SE graben showing discrete surface rupture generated by Holocene paleoearthquake activity. A main and an antithetic normal, NW–SE trending, active faults bound the basin. Paleoseismological evidence is reported on upslope-facing scarps of the antithetic fault, acting as dams to runoff, which contributed to temporary lacustrine conditions, as well as sediment uplift. The fluvial network in the area shows a poor drainage activity, whereas a present lake is dammed by the antithetic fault. The modern landscape is controlled by Holocene faulting, modifying the geological environment according to arthquake occurrence, from flat alluvial plains to lacustrine local basins. The application of the diffusion dating technique to unconsolidated sediments for the antithetic fault scarp indicates an age between 1 and 2 ka. Various geometric parameters have been obtained in order to reconstruct the paleoseismic history of the Cordovilla graben basin. The surface rupture and fault-offset values are associated with discrete active morpholineaments, parallel to the Pozohondo Fault. The Tobarra–Cordovilla segment (the structural boundary of the Cordovilla Basin) was generated by earthquakes with magnitudes (Mw) greater than 6.0, based on Wells and Coppersmith fault scarp relations.

Lacustrine deposits form most of the sedimentary record accumulated throughout the Miocene in the northern part of the Teruel Graben, a landlocked basin situated in NE Spain. Three main stratigraphic units ( Units I–III ) spanning Late Vallesian to Late Turolian in age, are distinguished in the area. The two former units comprise mainly carbonate lacustrine deposits that were deposited in a palustrine or a more permanent but shallow lacustrine setting, the latter being related mainly to periods of lake expansion under more humid and cooler climatic conditions. In contrast, deposition of Unit III, characterised by gypsiferous lacustrine sediments in central parts of the basin, reflects the influence of source rocks of evaporitic nature (Upper Triassic formations) that were emplaced by diapiric uplift in the eastern margin during the Middle Turolian. Carbonate lake sediments belonging to Units I and II consist of four main lithofacies associations: (a) distal–alluvial lake margin deposits; (b) lacustrine carbonates and pedogenically modified lacustrine carbonates; (c) carbonate fill channels; and (d) organic-rich marlstone and carbonate (marshes). Lithofacies association (a) shows typically a sequential arrangement formed, from bottom to top, of red mudstone, carbonate palaeosols and biomicrite beds (sequence type 1a). These sequences are interpreted as a result of slow but continuous aggradation of the floodplain areas and subsequent rise of the water table, probably reflecting equilibrium between subsidence and sedimentation. Lithofacies association (b) consisting of biomicrite beds passing upward into palaeosols (sequence type 1b) is thought to be caused by marked pulses of tectonic subsidence that created the accommodation space required for fast development of a carbonate lake. Carbonate fill channels, showing erosive lower surfaces dig out on previous channels, marsh deposits and/or lacustrine carbonates, exhibit well-developed prismatic structure at their bed tops. The sequential arrangement suggests similar tectonic constrains than the envisaged for lithofacies 1b. The comparison of depositional styles of the lake systems with the palaeoclimatic evolutionary pattern of the basin throughout the Miocene indicates that the combined effect of tectonism, climate and source rock played a major role in the stratigraphic framework of the basin during this period.

La presencia de sepiolita en los sedimentos neógenos (Aragoniense medio y superior) aparece ligada a paleoambientes de orla distal en abanicos aluviales. Dentro de ellos la formación de sepiolita tuvo lugar en charcas de carácter más o menos perenne próximas al borde de un lago salino, así como a cuerpos de agua desarrollados en la orla en momentos de retrogradación o estabilización relativa de los abanicos. Un último ambiente de formación de sepiolita son los perfiles de calcreta que aparecen ampliamente desarro­llados en estas zonas distales del sistema aluvial.

The PhD thesis deals with two different ironstone rock types encountered in two sedimentary successions (Upper Cretaceous and Lower Cenozoic) in the northern Bahariya, Egypt. Occurrence of the two iron-bearing rock types in a same area offers an opportunity to better understanding the origin of ironstone deposits. The ironstones occur as thin crusts within Cenomanian clastic rocks (Bahariya Formation) and as big ore bodies at three mine areas, associated to Eocene carbonate units. Analysis of the two ironstone types was carried out by means of field, petrographic, mineralogical and geochemical investigations. The ironstones contain similar iron-bearing minerals, mainly goethite and hematite, which display a variety of fabrics, i.e. concretionary, massive, stromatolitic-like, pisolithic, colloidal, reiniform aggregates, boxwork, leisegang, geode-like and brecciated. They show preferential replacement and cementation of carbonates by iron-rich minerals. Thus, the two ironstone types replaced both depositional and diagenetic carbonates (dolomites) with preservation of the structures, fabrics and thickness of their precursors. However, they exhibit some differences in textures, morphology and bed geometries but marked distinction in which refers to origin, mechanisms and timing of formation. The main mineral paragenesis in the Upper Cretaceous ironstones includes goethite, hematite, Fe-dolomite/ankerite and subordinate amounts of siderite, pyrolusite, todorokite, psilomelane and barite. In contrast, the Eocene ironstones show a more complex mineral paragenesis including goethite, hematite, quartz and subordinate amount of jarosite, alunite, barite, pyrolusite, jacobsite, romanechite, psilomelane, todorokite, apatite, palygorskite and kaolinite...