Fernández Barrenechea, José María

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First Name
José María
Last Name
Fernández Barrenechea
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Geológicas
Mineralogía y Petrología
Cristalografía y Mineralogía
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Now showing 1 - 10 of 10
  • Publication
    Sources of Sr and S in Aluminum-Phosphate–Sulfate Minerals in Early–Middle Triassic Sandstones (Iberian Ranges, Spain) and Paleoenvironmental Implications for the West Tethys
    (SEPM (Society for Sedimentary Geology), 2013) Galán Abellán, Ana Belén; Alonso Azcárate, Jacinto; Newton, Robert J.; Bottrell, Simon H.; Fernández Barrenechea, José María; Benito Moreno, María Isabel; Horra del Barco, Raúl de la; López Gómez, José; Luque del Villar, Francisco Javier
    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 formation of APS minerals during Early–Middle Triassic times, were established on the basis of Sr and S isotopic analyses. The S and Sr data (d34S V-CDT = +11 to +14% and 87Sr/86Sr = 0.7099–0.7247, respectively) can be interpreted as resulting from mixing of different sources. Strontium was sourced from the dissolution of pre-existing minerals like K-feldspar and clay minerals inherited from the source areas, causing high radiogenic values. However, the isotopic signal must also be influenced by other sources, such as marine or volcanic aerosol that decreased the total 87Sr/86Sr ratios. Marine and volcanic aerosols were also sources of sulfur, but the d34S was lowered by dissolution of pre-existing sulfides, mainly pyrite. Pyrite dissolution and volcanic aerosols would also trigger the acid conditions required for the precipitation of APS minerals. APS minerals in the study area are found mainly in the Cañizar Formation (Olenekian?–Aegian), which has the lowest 87Sr/86Sr ratios. The lower abundance of APS minerals in the Eslida Formation (Aegian–Pelsonian) may indicate change in the acidity of pore water towards more alkaline conditions, while the increased 87Sr/86Sr ratios imply decreased Sr input from volcanic activity and/or marine aerosol inputs during Anisian times. Therefore, the decrease in abundance of APS minerals from the Early to Middle Triassic and the variations in the sources of Sr and S are indicative of changes in paleoenvironmental conditions during the beginning of the Triassic Period. These changes from acid to more alkaline conditions are also coincident with the first appearance of carbonate paleosols, trace fossils, and plant fossils in the upper part of the Cañizar Formation (and more in the overlying Eslida Formation) and mark the beginning of biotic recovery in this area. The presence of APS minerals in other European basins of the Western Tethys (such as the German Basin, the Paris Basin and the southeastern France and Sardinia basins) could thus also indicate that unfavorable environmental conditions caused delay in biotic recovery in those areas. In general, the presence of APS minerals may be used as an indicator of arid, acidic conditions unfavorable to biotic colonization.
  • Publication
    Shallow burial dolomitisation of Middle–Upper Permian paleosols in an extensional tectonic context (SE Iberian Basin, Spain): Controls on temperature of precipitation and source of fluids
    (Elsevier, 2011) Benito Moreno, María Isabel; Horra del Barco, Raúl de la; López Gómez, José; Fernández Barrenechea, José María; Luque del Villar, Francisco Javier; Arche, Alfredo
    This work is focused on carbonate paleosols developed in three stratigraphic sections (Landete, Talayuelas and Henarejos) of theMiddle–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 stage that affected the Iberian Basin. The studied sections were located in two of these half-grabens, the Henarejos section being much closer to the basin boundary fault than the other two sections. The mineralogy and texture of the carbonate precursor of paleosols in the three studied sections are not preserved because original carbonate is replaced by coarse crystals of dolomite and/or magnesite. Dolomite crystals are typically euhedral, displaying rhombohedral shapes and reddish luminescence, although in the Henarejos section dolomite displays non-planar boundaries and frequently saddle habit. Micas are deformed and adapted to dolomite crystals, which, in turn, are affected by stylolites, suggesting that dolomite precipitated before mechanical and chemical compaction. Carbon and oxygen isotopic compositions of dolomite fromthe three sections showdifferent values (δ13CVPDB mean values=−6.7‰,−5.5‰ and −7.5‰; δ18OVPDB mean values=−4.0‰; –5.6‰and−8.2‰, at Landete, Talayuelas and Henarejos sections, respectively). The 87Sr/86Sr ratios are similar in the three sections yielding values between 0.71391 and 0.72213. The petrographic and geochemical features of dolomite in the three studied sections suggest precipitation fromsimilar fluids and during shallow burial diagenesis. Assuming that theminimum temperature for dolomite precipitation in the Henarejos sectionwas 60 °C (as suggested by the presence of non-planar saddle habit), and that the dolomitizing fluid had similar δ18O values at the three localities, then dolomite in the Talayuelas and Landete sections precipitated at temperatures around 16 and 25 °C cooler, respectively. In addition, the δ18OVSMOW values of the water from which dolomite precipitated would have ranged between −0.3 and −2.9‰. Dolomite is partially or totally replaced by non- to dark dull luminescent magnesite in the Landete and Talayuelas sections. Magnesite crystals are affected by stylolites, indicating that it precipitated before chemical compaction. The δ13C mean values are −6.5 and −6.0‰ and the δ18OVPDB mean values are −6.7 and −7.8‰, in the Landete and Talayuelas sections, respectively. The 87Sr/86Sr ratios of magnesite are similar in both sections yielding values between 0.71258 and 0.72508. This suggests that they probably precipitated from similar fluids during progressive burial and at higher temperatures than dolomites at the same sections. Assuming thatmagnesite precipitated froma fluid with similar δ18O values in both sections, then it had to precipitate at a temperature around 8 °C higher in Talayuelas than in the Landete section. Dolomitisation and magnesite precipitation probably occurred via reflux of saline to hypersaline brines from the overlying Mid-Late Triassic Muschelkalk and/or Keuper facies. The temperatures inferred for dolomite precipitation, however, are too high for shallow burial if a normal geothermal gradient is applied. Thus, it can be inferred that salinefluidswere heated as theyflowed through the syn-sedimentary extensional faults that controlledMiddle Permian to Middle Triassic sedimentation; consequently fluidswould have been at higher temperatures near the Henarejos area, which was closer to the basin boundary fault than at the Talayuelas and Landete areas, whichwere situated further away. This contention is in agreement with recent studies which demonstrate that an important thermal event took place during Late Triassic–Early Jurassic times in the Iberian Peninsula.
  • Publication
    Palaeoenvironmental significance of Late Permian palaeosols in the South-Eastern Iberian Ranges, Spain
    (Blackwell Publishing Ltd, 2008) Horra del Barco, Raúl de la; Benito Moreno, María Isabel; López Gómez, José; Arche, Alfredo; Fernández Barrenechea, José María; Luque del Villar, Francisco Javier
    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 palaeogeographical distribution, to be distinguished throughout the South-eastern Iberian Basin. These characteristics are, in turn, related to topographic, climatic and tectonic controls. The vertical distribution of the palaeosols is used to differentiate the formation in three parts from bottom to top showing both drastic and gradual vertical upwards palaeoenvironmental changes in the sections. Reconstruction of palaeoenvironmental conditions based on palaeosols provides evidence for understanding the events that occurred during the Late Permian, some few millions of years before the well-known Permian-Triassic global crisis.
  • Publication
    Geochemical markers of paleoenvironments, weathering, and provenance in Permian–Triassic terrestrial sediments
    (SEPM, 2020) Galán Abellán, Ana Belén; Fernández Barrenechea, José María; Horra del Barco, Raúl de la; Alonso Azcárate, Jacinto; Luque del Villar, Francisco Javier; Borruel Abadía, Violeta; López Gómez, José
    This study compares several geochemical factors (major and minor rare earth elements, Ti/Al ratios, and chemical index of alteration, CIA, values) in the Early Triassic Cañizar Formation (Fm) (Buntsandtein facies) of E Iberia with those of adjacent Middle Permian and Middle Triassic units (Alcotas and Eslida fms, respectively). According to significant differences detected, it seems that most geochemical perturbation occurred during the Early Triassic. Variations in Ti/Al ratios suggest changes in source areas between the studied units and even within the Cañizar Fm. These provenance changes correlate with successive tectonic pulses during the opening and development of the Iberian Basin, as they can be linked to major sedimentary surfaces and unconformities, as well as major sedimentological variations. Ti enrichment in the lower and middle part of the Cañizar Fm, together with high Sr and P concentrations, may be indicative of environmental alterations related to acid meteoric waters. Moreover, this acid alteration took place under arid conditions as reflected by CIA values, indicating that during the deposition of the Cañizar Fm, variable but predominantly physical weathering prevailed in contrast to the chemical weathering that took place when the Alcotas and Eslida formations were deposited. Our data along with the known fossil record of the study area indicate that during the Middle–Late Permian and Early Triassic, conditions in this tectonically active area changed from humid to arid-acid, hampering biotic recovery. Then, during late Early–Middle Triassic times, the return of more humid and less acid environments promoted biotic development. Geochemical markers emerged as useful tools complementary to sedimentological, paleontological, and tectonic data for unveiling paleoenvironmental events, especially in a setting of significant regional change.
  • Publication
    Late Permian continental sediments in the SE Iberian Ranges, eastern Spain: Petrological and mineralogical characteristics and palaeoenvironmental significance
    (Elsevier, 2005) Benito Moreno, María Isabel; Horra del Barco, Raúl de la; Fernández Barrenechea, José María; López Gómez, José; Rodas, Magdalena; Alonso Azcárate, Jacinto; Arche, Alfredo; Luque del Villar, Francisco Javier
    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 Formation). The lower part includes abundant and well-preserved carbonate paleosol profiles and fine-grained sediments made up by quartz, feldspar, hematite and illite, with scarce kaolinite. The preservation of dolomicrite in some paleosols suggests that they originally developed as dolocretes in an arid to semi-arid climate with marked seasonality. A change towards more humid and acid conditions can be deduced from the presence of siderite and goethite in paleosols in the middle part of the Alcotas Formation. Moreover, the presence of plant remains, coal beds and/or carbonaceous shales at the top of the middle part, and the lack of carbonate paleosols in the upper part of the formation would indicate a further step towards acid conditions. These conditions would increase until the Early Triassic, as indicated by the lack of carbonates and the presence of Sr-rich aluminium phosphate sulphates (APS minerals) at the base of the Triassic (Can˜ izar Formation), which clearly indicates extreme acid conditions during the Permian–Triassic transition of the study area.
  • Publication
    First report of a Middle-Upper Permian magmatism in the SE Iberian Ranges: characterisation and comparison with coeval magmatisms in the western Tethys
    (Universidad Complutense de Madrid, 2012) Lago San José, Marceliano; Horra del Barco, Raúl de la; Ubide Garralda, Teresa; Galé, Carlos; Galán Abellán, Ana Belén; Fernández Barrenechea, José María; López Gómez, José; Benito Moreno, María Isabel; Arche, Alfredo; Alonso Azcárate, Jacinto; Luque del Villar, Francisco Javier; Timmerman, Martin J.
    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 igneous rocks are classified as basaltic andesites. They show a subophitic microstructure constituted by plagioclase (An62 – An6), augite (En48Wo44Fs7 –En46Wo39Fs15), pseudomorphosed olivine, minor amounts of oxides (magnetite and ilmenite)and accessory F-apatite. According to the mineralogy and whole-rock composition, their geochemical affinity is transitional from subalkaline to alkaline. Radiometric dating of the sill is not feasible due to its significant alteration. Field criteria, however, suggest an emplacement coeval to the deposition of the Alcotas Formation (Middle-Upper Permian). This hypothesis is supported by the transitional affinity of these rocks, similar to other Middle-Upper Permian magmatisms in the western Tethys, e.g., from the Pyrenees. Taking into account their isotopic signature (εSr: -6.8 to -9.2; εNd:+1.7 to +8.3), an enriched mantle source with the involvement of a HIMU component has been identified. This interpretation is supported by the trace element contents. Some of these HIMU characteristics have been recognised in the Middle-Upper Permian magmatisms of the Central Pyrenees (Anayet Basin) and the High Atlas (Argana Basin). However, none of these source features are shared with other Middle-Upper Permian magmatisms of the western Tethys (Catalonian Coastal Ranges, Corsica-Sardinia and southern France), nor with the Lower Permian magmatism of the Iberian Ranges. These differences support the presence of a heterogeneous mantle in the western Tethys during the Permian.
  • Publication
    Quantifying aluminium phosphate–sulphate minerals as markers of acidic conditions during the Permian–Triassic transition in the Iberian Ranges, E Spain
    (Elsevier Science B.V., Amsterdam., 2016-07) Borruel Abadía, Violeta; Fernández Barrenechea, José María; Galán Abellán, Ana Belén; Alonso Azcárate, Jacinto; Horra del Barco,, Raúl, De la; Luque del Villar, Francisco Javier; López Gómez, José
    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 their small size, low concentrations, and optical properties. By comparing the element maps obtained for the rocks in the study area of the Iberian Ranges (E Spain) with the results of whole rock analysis and with factors indicating the presence of life (bioturbation, palaeosols, and macro-plant remains), it has been possible to correlate relatively high levels of APS minerals in the first sedimentary record (Cañizar Formation) after the Permian–Triassic boundary, with the lack of living organisms. The APS are related to early diagenetic phases precipitated at low pH conditions and are therefore markers of formation in an acidic environment. Our findings suggest a long period of sustained acidic conditions followed by an environmental change linked with the recovery of life and with lower APS mineral contents. This change is detected at the top of the Cañizar Formation, at the end of the Sphatian. The method proposed could be used as a tool to address the environmental changes that took place during the Permian–Triassic transition in continental environments
  • Publication
    Could acidity be the reason behind the Early Triassic biotic crisis on land?
    (Elsevier, 2019-06-20) Borruel-Abadía, Violeta; Fernández Barrenechea, José María; Galán-Abellán, Belén; Horra del Barco, Raúl de la; López Gómez, José; Ronchi, Ausonio; Luque del Villar, Francisco Javier; Alonso Azcárate, Jacinto; Marzo Carpio, Mariano
    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 subequatorial latitudes. Similar distribution patterns of aluminum phosphate-sulfate (APS) minerals contents in these rocks in the four studied basins provide evidence of increased acidity during the Smithian-Spathian transition, coinciding with a lack of indicators of organic activity in the same interval. Thus, this period of high acidity on land, may have been one of the causes of this biological crisis. Based on the quantification of APS minerals in the studied sedimentary sequences, we propose that it was not until acidity in the environment diminished, that biotic recovery was possible. APS data may also be useful to interpret other past biotic crises.
  • Publication
    Paleoecological and paleoenvironmental changes during the continental Middle–Late Permian transition at the SE Iberian Ranges, Spain
    (Elsevier, B.V., 2012) Horra del Barco, Raúl de la; Galán Abellán, Ana Belén; López Gómez, José; Sheldon, N.D.; Fernández Barrenechea, José María; Luque del Villar, Francisco Javier; Arche, Alfredo; Benito Moreno, María Isabel
    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 Middle subunits of the Middle Permian Alcotas Formation indicates a significant paleoclimatic change from arid and semiarid conditions towards more humid conditions. Coincident with the onset of humid conditions there were changes in the sedimentology, mineralogy, and geochemistry that indicate significant environmental changes including a shift in weathering intensity and a change of fluvial style from braided to meandering systems. Near the top of the Middle Subunit, a local biotic crisis is recorded by palynomorph assemblages. Following this crisis, there is a total absence of coal beds, plant remains, and microflora that defines a barren zone in the uppermost part of the Alcotas Formation which is recorded throughout the basin. The barren zone is accompanied by a shift back to braided stream systems, but not by a return to carbonate-bearing paleosols indicative of arid or semi-arid conditions. This combination of features is consistent with other Middle–Late continental basins related with mass extinctions, so the barren zone is interpreted as the extinction interval. The regional character of the extinction interval and its proximity with the Middle–Late Permian transition could be related with the global mid-Capitanian biotic turnover described in this period of time in other marine basins. However, the common difficulties of dating with precision non-marine rocks make this relationship difficult to probe in the Iberian Basin and in other Middle– Late Permian basins. Further work, including high resolution carbon-isotope analyses and complete studies of the magnetostratigraphy, should be desirable in order to obtain a better age constraint and to produce reliable comparisons with marine sections.
  • Publication
    Palaeogeographical significance of clay mineral assemblages in the Permian and Triassic sediments of the SE Iberian Ranges, eastern Spain
    (Elsevier, 1997) Alonso Azcárate, Jacinto; Arche, Alfredo; Fernández Barrenechea, José María; López Gómez, José; Luque del Villar, Francisco Javier; Rodas, Magdalena
    The evolution of the palaeogeography of the SE Iberian Basin during the Permian and Triassic represents a general evolution from continental to marine environments. It has been recently studied from the sedimentological, stratigraphical, tectonic and palaeontological points of view. In spite of these results, many aspects of this palaeogeography are still a matter of discussion. In this study, clay mineralogy analysis complements previous studies representing a new aspect for understanding the evolution of the sedimentary environment and the palaeogeography of the Iberian Basin during the periods in question and thus of the palaeogeography and the location of the major high areas in the westernmost border of the Tethys sea. In spite of late diagenetic transformations the original clay mineral associations of the Permian-Triassic sediments of the SE Iberian Ranges can be reconstructed. Seventy-seven samples of siliciclastic and carbonate sediments of these ages have been studied (SEM and XRD), revealing six new aspects that help to precise the palaeogeographical interpretation of the area: (1) Two major mineral assemblages have been found: illite+ kaolinite +pyrophyllite in the continental facies and illite + chlorite + vermiculite + mixed-layer clays in the marine facies. (2) The Mg-rich clay minerals are here considered to be of marine origin. (3) Active phases of basin boundary faults are marked in the sediments by the presence of pyrophyllite, derived directly from the Palaeozoic metamorphic basement. (4) Unconformities separating major depositional sequences also separate formations with different clay mineralogy. (5) Different groups of clay minerals can be separated clearly coinciding with the different palaeogeographical stages also distinguished in the westernmost border of the Tethys sea. (6) The clay mineral associations back up the data of a previous hypothesis of a humid climate for the end of the Permian in the study area just prior to the first incursion of the Tethys sea.