José F. Barrenechea

Complutense University of Madrid | UCM · Department of Mineralogy and Crystallography

We report on a multi-proxy study of the Carnian Pluvial Episode in the continental Argana Basin (Morocco) based on mineralogy, geochemistry, paleosols and sedimentary features. The study focus on two sections of the Irohalene Member (unit t5) of the Timezgadiouine Formation dated as late Julian-early Tuvalian through clam shrimp (conchostracan) ass...

Until very recently, the early Alpine Permian-Triassic tectono-sedimentary phases preserved in the Cantabrian Mountains have suffered from important stratigraphic mismatches and wrong tectonics interpretations. The lack of precise ages and misunderstanding of the stratigraphical units were the main causes behind these problems. In consequence, the...

The scarce evidence of paleontological records between the upper Permian and the Anisian (Middle Triassic) of Western Europe could reflect (1) large stratigraphic gaps in the continental successions and/or (2) the persistence of disturbed conditions after the Permian–Triassic Boundary extinction event and the succession of ecological crises that oc...

Several siltstone/claystone levels of the Permian succession in the Southern Pyrenees were sampled for a detailed palynostratigraphic study. A new well preserved palynological assemblage was obtained from this succession, which stands out because of its red continental deposits interlayered by volcanic rocks radiometrically dated (281.5 ±2.3 Ma and...

The Permian-Triassic rifting represents the first of the two Mesozoic rifting stages recorded in the Iberian Peninsula. Its first phases of development started during the Early Permian, and were linked to the beginning of the break-up of Pangea, the large, unique and rheologically unstable supercontinent that mainly resulted from the collision of G...

In recent years there is growing evidence of the importance of the Smithian-Spathian (Early Triassic) ecological crisis to explain the delayed recovery of life after the Permian-Triassic Boundary mass extinction. This study focuses on sedimentary continental rocks of middle Permian to Middle Triassic age from four different Peritethys basins in sub...

In their paper, Mujal et al. (2017) describe as exceptional a section in the E Pyrenees (namely the Coll de Terrers), considering it a continental succession that continuously spans in time from the Late Permian to the Early Triassic. These authors describe the sandy-clayey red-beds of the upper Buntsandstein unit as the upper part of the Upper Red...

In the western European basins, the paleoflora of late Pennsylvanian-early Permian transition is still a matter of discussion in terms of its age determination and biostratigraphic ranges. This study represents a review of the Upper Carboniferous and Permian stratigraphy of the Central and Eastern Pyrenees from continental successions with interbed...

The Pyrenean-Cantabrian Orogen arose through the collision of the Iberian and Eurasian plates, mostly in Cenozoic times. This orogen comprises two main mountain ranges, the Pyrenees to the east, and the Cantabrian Mountains to the west. To date, the early Alpine tectono-sedimentary phases preserved in the Cantabrian Mountains, of Permian and Triass...

The break-up of Pangea remains one of the most interesting moments in the Earth's history. In the Pyrenees this geological moment is represented by continental successions, giving rise to a magnificent example of the creation of new basins and their sedimentary fill. In this work we present a study based on stratigraphy, sedimentology and synsedime...

This study examines rainfall variations of the Mid-Carnian Pluvial Episode (CPE) based on the continental fluvial sedimentology, palaeosol and clay mineralogy records of the Stable Meseta (eastern Spain). In the formation examined, the Manuel Fm or K2 Fm, the CPE is represented by three regressive–transgressive sequences, or subunits K2.1, K2.2 and...

The Upper Carboniferous–early Permian stratigraphic succession of the Pyrenees is represented by the volcanic-volcanoclastic deposits of the Grey Unit (GU), followed by the fluvial and lacustrine deposits of the Transition Unit and the Lower Red Unit (Gisbert, 1981). The present work shows new palynological data from the GU. The GU is defined prima...

The Triassic record in the SE Iberian Ranges starts with two tecto-sedimentary units of continental origin in Buntsandstein facies: and Cañizar and Eslida Formations. The Eslida Formation consists of sandstone bodies intercalated with thick, red siltstone beds. Where this unit is presented, it lies always conformably layers on top of the Cañizar Fo...

The late Palaeozoic-early Mesozoic stratigraphic succession of the Central Pyrenees provides the opportunity to study the evolution of sedimentary and volcano-sedimentary units deposited in a series of intracontinental basins. The genesis of these basins starts with a permo-carboniferous post-collisional, strike-slip tectonics, followed by an Early...

The late Carboniferous-Lower Triassic basins of the Central-eastern Pyrenees are the result of the post-orogenic transtension and extension after the Variscan orogeny. Several intramontane continental troughs formed in SW Europe following the Upper Carboniferous-Lower Permian crustal-scale dextral shearing. In this geodynamic scenario, a strong tec...

The Sierra of Ayllon in Central Spain has a rich heritage from both the architectonic and geological perspectives. On one hand, the low lands flanking the northern side of the sierra in the Segovia Province host the so-called red hamlets and black hamlets (pueblos rojos-pueblos negros). The red and black terms derive from the traditional local buil...

The Sierra of Ayllón in Central Spain has a rich heritage from both the architectonic and geological perspectives. On one hand, the low lands flanking the northern side of the sierra in the Segovia Province host the so-called red hamlets and black hamlets (pueblos rojos-pueblos negros). The red and black terms derive from the traditional local buil...

The Permian and Triassic successions of the Catalan Pyrenees provide key information on the stratigraphic and paleontological record of Southern Europe. These deposits are encompassed in a long terrestrial succession ranging from the Late Carboniferous to the Middle Triassic, having been historically studied by different disciplines (e.g., Mey et a...

After some pioneering studies during the sixties and eighties of the last century, a few researches have been carried out on the continental Permian to Triassic sedimentary successions of central Pyrenees since the very recent and detailed insights of Gretter et al. (2015) and Mujal et al. (2016). In the frame of these last works, our aim is to cla...

The continental Permian-Triassic transition in southern Europe presents little paleontological evidence of the Permian mass extinction and the subsequent faunal recovery during the early stages of the Triassic. New stratigraphic, sedimentological and paleontological analyses from Middle-Upper Permian to Lower-Middle Triassic deposits of the Catalan...

In this paper, a method based on element mapping of randomly selected areas of thin sections on electron microprobe is proposed to quantify the relative contents of strontium-rich hydrated aluminium phosphate-sulphate (APS) minerals in siliciclastic continental sedimentary rocks. The main problems for these minerals to be quantified are related to...

Devonian marbles within the internal aureole of the Panticosa Pluton contain good examples of vesuvianite that were overlooked. The pluton emplacement provoked recrystallization of the regional low-grade organic matter-bearing limestones and the formation of skarnoids at the expenses of interbedded siliclastic layers. The latter contain large cryst...

Until recently the climate of the Early–Middle Triassic at low latitudes was broadly considered as generally temperate-warm with no major climate oscillations. This work examines the climate of this period through a detailed study of the sedimentary, plant, soil and mineral records of continental rocks (Buntsandstein facies) in eastern Iberian basi...

The Eastern Catalan Pyrenees form the southernmost segment of the Pyrenean Axial Zone. They experienced complex multistage process as the result of both the Variscan and the Pyrenean orogenic cycles. After the Late Palaeozoic, several small extensional sub-basins were filled by continental successions as a response to the changing tectonic setting...

Quantitative phase analysis (QPA) of clayey materials using X-Ray diffraction data has always been a challenge. While quantitative methods based on Rietveld analysis offer excellent results for non-clay minerals, they become problematic when high crystallochemical and order degree variations are present in the phases, as is the case of most clay mi...

The end of the Permian period is characterized by the largest mass extinction ever recorded in marine and terrestrial sedimentary rocks. The oldest plant macro-remains after the P–T boundary recorded in the Castilian Branch of the Iberian Range after this mass extinction belong to the Eslida Formation of Anisian age. These associations have been re...

The mantle is the largest reservoir of carbon on Earth. The mantle provides CO2 to the surface through degassing and magmatism whereas carbon from sediments (as carbonaceous matter) and altered oceanic crust (mostly as calcite veinlets) can be recycled into the mantle through subduction. This idealized cycle can be disrupted as a consequence of the...

The Upper Carboniferous–Early Triassic stratigraphic succession of Catalan Pyrenees consists of volcano-sedimentary Units that deposited in intracontinental sub-basins. The genesis of these troughs, starts with a post-collisional, strike-slip tectonic, followed by a Permian extensional setting with fluvial and lacustrine facies accompanied by exten...

The Early Triassic was still marked by the general perturbations related to the drastic palaeoenvironmental changes that occurred around the Permian–Triassic transition. These perturbations affected both marine and continental environments and were caused by events such as massive volcanism from the Siberian Traps and the consequent general geochem...

Graphite deposits result from the metamorphism of sedimentary rocks rich in carbonaceous matter or from precipitation from carbon-bearing fluids (or melts). The latter process forms vein deposits which are structurally controlled and usually occur in granulites or igneous rocks. The origin of carbon, the mechanisms of transport, and the factors con...

The Early–Middle Triassic siliciclastic deposits of the Catalan Ranges, NE Spain, are dominated by aeolian sediments indicating a predominance of arid climate during this time span, in sharp contrast with the coeval fluvial sediments found in the Castilian Branch of the Iberian Ranges, 300 km to the SW. The NE–SW-oriented Catalan Basin evolved duri...

The presence of Sr-rich aluminium-phosphate sulphate (APS) minerals in continental sedimentary rocks from the Cañizar and Eslida Formations along the eastern part of the Iberian Range (Spain) is considered as evidence of acidic and oxidising conditions during Early–Middle Triassic times. The formation of APS minerals occurred shortly after sediment...

Aluminum-phosphate-sulfate (APS) minerals, formed during early diagenesis in relation to acid meteoric waters, are the main host of Sr and S in the Early-Middle Triassic continental sandstones of the Iberian Ranges (east of the Iberian Peninsula). The sources of these elements and the effects of paleoenvironmetal changes on these sources and on the...

A multiple basic to intermediate sill is reported for the first time in the south-eastern Iberian Ranges. It is composed of several tabular to irregular levels intercalated within the fl uvial sediments of the Alcotas Formation (Middle-Upper Permian). The sill could represent the youngest Paleozoic subvolcanic intrusion in the Iberian Ranges. The i...

The Middle and Late Permian are characterized by a pair of mass-extinction events that are recorded in both marine and continental environments. Here, we present the first continental western peri-Tethyan record of an extinction event located in the Middle–Late interval. In the SE Iberian Ranges, Central Spain, the transition between the Lower and...

Massive graphite deposition resulting in volumetrically large occurrences in volcanic environments is usually hindered by the low carbon contents of magmas and by the degassing processes occurring during and after magma emplacement. In spite of this, two graphite deposits are known worldwide associated with volcanic settings, at Borrowdale, UK, and...

Graphite in the Borrowdale (Cumbria, UK) deposit occurs as large masses within mineralized pipe-like bodies, in late graphite–chlorite veins, and disseminated through the volcanic host rocks. This occurrence shows the greatest variety of crystalline graphite morphologies recognized to date from a single deposit. These morphologies described herein...

The Permian–Triassic transition (P–T) was marked by important geochemical perturbations and the largest known life crisis. Consequences of this event, as oxygen-depleted conditions and the unusual behavior of the carbon cycle, were prolonged during the Early Triassic interval delaying the recovery of life in both terrestrial and marine ecosystems....

The provenance of the Permo-Triassic series of the Talayuelas anticline (Iberian Ranges) have been studied using U-Pb geochronology (laser ablation inductively coupled plasma mass spectrometry) of detrital zircons. These intracontinental siliciclastic series were formed by extensive sandy braided fluvial systems associated with ephemeral lake depos...

Stable carbon isotope geochemistry provides important information for the recognition of fundamental isotope exchange processes related to the movement of carbon in the lithosphere and permits the elaboration of models for the global carbon cycle. Carbon isotope ratios in fluid-deposited graphite are powerful tools for unravelling the ultimate orig...

A multiple basic to intermediate sill is reported for the first time in the south-eastern Iberian Ranges. It is composed of several tabular to irregular levels intercalated within the fluvial sediments of the Alcotas Formation (Middle-Upper Permian). The sill could represent the youngest Paleozoic subvolcanic intrusion in the Iberian Ranges. The ig...

The microstructure and mineralogy of lightweight aggregates manufactured with washing aggregate sludge, sewage sludge and a clay-rich sediment have been studied. The mineralogical analysis revealed the neo-formation of plagioclase and pyroxene group minerals and a minor presence of gehlenite. Some relationships may be established: (i) heating tempe...

The Permian and Triassic rocks of the Iberian Range are in general well exposed. Most of these outcrops are related to anticlines resulting from Cenozoic compresional events, and clearly inherit the ancient fault lineaments that controlled their sedimentation in the Iberian Basin. These rocks show specific characteristics related to the asymmetrica...

This work is focused on carbonate paleosols developed in three stratigraphic sections (Landete, Talayuelas and Henarejos) of the Middle–Late Permian Alcotas Formation in the SE Iberian Basin. The Alcotas Formation, of alluvial origin, was deposited in semi-connected half-grabens developed during the early stages of the Permian–Triassic rifting stag...

A multiple basic to intermediate sill is reported for the first time in the south-eastern Iberian Ranges. It is composed of several tabular to irregular levels intercalated within the fl uvial sediments of the Alcotas Formation (Middle-Upper Permian). The sill could represent the youngest Paleozoic subvolcanic intrusion in the Iberian Ranges. The i...

The microstructures and mineralogical compositions of lightweight aggregates (LWAs) manufactured with washing aggregate sludge (WS), fly ash (FA) and used motor oil (UMO) have been studied. Most LWAs with WS and FA exhibited an external layer and a glassy core with isolated pores. LWAs with WS and UMO did not present external shells or signs of blo...

Permian and Triassic alluvial sediments of the Iberian Range, an intracratonic, linear alpine structure occupying central and eastern Spain, were deposited in the fault-bounded Iberian Basin during an extensional period. The earliest sedimentary infill consists of alluvial deposits subdivided into three unconformity-bounded macrosequences. The seco...

The volcanic-hosted graphite deposit at Borrowdale in Cumbria, UK, was formed through precipitation from C–O–H fluids. The δ13C data indicate that carbon was incorporated into the mineralizing fluids by assimilation of carbonaceous metapelites of the Skiddaw Group by andesite magmas of the Borrowdale Volcanic Group. The graphite mineralization occu...

The Iberian Basin or its present-day expression, the Iberian Ranges, was refilled with red bed sediments of alluvial origin during the late Olenekian–Anisian period represented by the Cañizar (Olenekian–Anisian) and Eslida (Anisian) Formations, both commonly known as Buntsandstein facies. In the late part of the Anisian, the Tethys Sea reached the...

En este trabajo se describen las experiencias llevadas a cabo en la utilización de medios digitales en cartografía geológica con los alumnos de la Facultad de CC. Geológicas. Los trabajos realizados, con financiación parcial del proyecto de innovación (PINMAD-86, 2007), han permitido poner a disposición de los alumnos algunos de los medios digitale...

Recognized large occurrences of fluid-deposited graphite displaying high crystallinity were previously restricted to high-temperature environments (mainly granulite facies terranes). However, in the extensively mined Borrowdale deposit (UK), the mineralogical assemblage, notably the graphite-epidote intergrowths, shows that fully ordered graphite p...

The species rubra sp. nov., a new triadotypomorphan insect from the Iberian Ranges, is described on the basis of a newly discovered specimen, found in fine grained sandstones of alluvial origin, in the lowermost part of the Eslida Formation (Buntsandstein facies), in the central part of the Iberian Ranges. The occurrence of a triadotypomorphan sugg...

The Late Permian (Wuchiapingian) Alcotas Formation in the SE Iberian Ranges consists of one red alluvial succession where abundant soil profiles developed. Detailed petrographical and sedimentological studies in seven sections of the Alcotas Formation allow six different types of palaeosols, with distinctive characteristics and different palaeogeog...

The present study focuses on the diversity and paleovegetational significance of the floristic record of the Late Permian continental Alcotas Formation, in five sections of the southeastern Iberian Ranges, central Spain. This unit, of Upper Tatarian or Lower Lopingian (Upper Permian) age, can be subdivided into three parts, represented by sediments...

The conditions of the bentonite in an engineered barrier for HLW disposal have been simulated in a laboratory test. Six cylindrical blocks of bentonite compacted at a dry density of 1.64 g/cm³ were piled up in a hermetic Teflon cell. The total length of the clay column inside the cell was 60 cm. The bottom surface of the bentonite was heated at 100...

This paper examines the effects of shear stress on the structural parameters that define the 'crystallinity' of graphite. The results show that highly crystalline graphite samples ground for up to 120 min do not undergo detectable changes in the three-dimensional arrangement of carbon layers but crystallite sizes (Lc and La) decrease consistently w...

A detailed mineralogical and petrological study and the analysis of paleosol profiles in continental alluvial sediments of the Late Permian in the SE Iberian Ranges (Spain) allow us to infer the significant environmental changes that occurred during this time period. Three parts have been distinguished in the Late Permian sediments (Alcotas Formati...

This paper describes a vein-shaped graphite occurrence in which, for the first time, the geological, mineralogical and isotopic evidence support its formation by physical remobilization of previously formed syngenetic graphite. The deposit studied is located in the Spanish Central System and it occurs along the contact between a hydrothermal Ag-bea...

Variations in clay mineral assemblages, changes in Kubler index (KI), and the chemical composition of chlorites are used to identify source areas in the lacustrine materials in the Lower Cretaceous Leza Limestone Formation of the Cameros Basin, northern Spain. This formation has fairly homogeneous lithological characteristics and facies association...

The significance of syngenetic and epigenetic graphite occurrences from the Variscan high-temperature/low-pressure Aracena Metamorphic Belt is discussed in the framework of the tectono-thermal evolution of this southern zone of the Iberian Massif. Syngenetic graphite is associated with both low- to medium-grade metamorphic rocks (La Umbría series,...

This paper describes a rare occurrence of nontronite associated with sulfide-bearing felsic metavolcanics, providing evidence of colloidal deposition in open spaces as result of a low-temperature water-rock interaction. Microbotryoidal masses of green nontronite with impurities of kaolinite, illite, barite, amorphous silica and iron oxyhydroxides a...

The Cameros Basin in Central Spain is an intraplate rift basin that developed from Late Jurassic to Middle Albian time along NW-SE trending troughs. The sedimentary basin fill was deposited predominantly in continental environments and comprises several depositional sequences. These sequences consist of fluvial sandstones that commonly pass upward...