Person:
Rossi Nieto, Carlos

First Name

Carlos

Last Name

Rossi Nieto

URI

https://hdl.handle.net/20.500.14352/75285

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Ciencias Geológicas

Department

Mineralogía y Petrología

Area

Petrología y Geoquímica

Identifiers

Full item page

Search Results

Now showing 1 - 10 of 24

Exceptional preservation of Mn-oxidizing microbes in cave stromatolites (El Soplao, Spain)
(Sedimentary Geology, 2012) Lozano Fernández, Rafael; Rossi Nieto, Carlos
Many ferromanganese stromatolites of El Soplao Cave (N Spain) are characterized for the exceptional preservation and high diversity of ferromanganese stromatolites , probably representing the best example of microbial preservation described in ferromanganese deposits so far. The El Soplao stromatolites are mainly formed by polymetallic Mn-rich oxides with subordinate and variable amounts of detrital material, and consist of both dendritic and laminar microfacies. In both microfacies, microbial forms are abundant in the relatively pure Mn-oxide rich material, whereas they are scarce in areas with significant detrital material. Microbial forms are observed either in cross section, completely embedded in the Mn-oxide-rich matrix, or in three dimensions lining the walls of pores. Based on their morphology, we have separated the most abundant microbial forms into six main morphotypes and six additional submorphotypes, most of which can be assigned to bacteria. Most morphotypes consist of coccoid, coccobacilus, or filamentous forms. Therefore they are not diagnostic of any particular bacterial group. However, the ovoid cells of morphotype B show cylindrical polar protuberances typical of prosthecate alpha-Proteobacteria. On the basis of characteristic morphological features, three submorphotypes of morphotype B can be assigned to three alpha-Proteobacteria genera: Hyphomicrobium, Pedomicrobium, and Caulobacter. This ascription is supported by the well known Mn-oxidizing behavior of both Pedomicrobium and Caulobacter, and by the common presence of Hyphomicrobium in ferromanganese deposits elsewhere. The excellent microbial preservation is partly related to the origin of the ferromanganese oxides, i.e. extracellular precipitation induced by microbial metabolism. Other factors contributing to the good microbial preservation are the relatively low degree of diagenetic alteration, and the relatively high accretion rates of stromatolites compared to other ferromanganese deposits. The generally low degree of diagenesis is likely because the stromatolites have remained relatively stable and at a rather low temperature since they were formed at least 1 Ma ago. Still, some stromatolites have suffered diagenetic alteration (partial dissolution and replacement by calcium carbonates and Fe-rich oxides), obscuring or even obliterating their bioforms. The El Soplao case represents an example of how easily biogenic Mn oxides can be altered, and their bioforms blurred, in a relatively short geological time span in spite of being in a relatively stable, alkaline, and low-temperature setting. A geological implication is that the absence of bioforms in other ferromanganese deposits, including rock varnish and Precambrian iron formations, does not disprove their possible biogenic origin, since the high chemical reactivity of biogenic manganese oxides makes them highly vulnerable to diagenesis.
Younger Dryas to Early Holocene paleoclimate in Cantabria (N Spain): Constraints from speleothem Mg, annual fluorescence banding and stable isotope records
(Quaternary Science Reviews, 2018) Rossi Nieto, Carlos; Bajo, Petra; Lozano, Rafael P.; Hellstrom, John
The Younger Dryas (YD) stadial represents the most abrupt climate change of the Earth's recent history. Thus, understanding its causes and different local responses is relevant for Quaternary paleoclimatology. We present a speleothem high-resolution proxy record of the Lateglacial to Early Holocene paleoclimate of the Cantabrian Cordillera (N Spain), a strategic location to evaluate the influence of North Atlantic events such as the YD on South-Western Europe. Fluorescence lamination, growth-rate, stable-isotope, and [Mg] records from stalagmite SIR-1 were dated using an age-depth model constrained by U-Th dates and annual-lamina counting. The YD is recorded as a prominent positive δ13C excursion whose chronology (12.95 ± 0.14 to 11.62 ± 0.16 ka) and shape closely agree with the GS-1 stadial as defined in Greenland ice, supporting the event synchronicity in both areas. A colder and drier YD climate limited soil productivity and dripwater availability, leading to higher δ13C and [Mg], reduced growth rate, and virtually absent fluorescence lamination. The early YD record (until ∼12.5 ka) reflects increasing aridity, whereas the late YD (from ∼12.2 ka on) shows the opposite trend. At the YD boundaries, temperature changes influenced the [Mg] record by modifying the Mg partition into calcite. However, this effect was superseded by major changes in dripwater Mg/Ca linked to rainfall variations. During the Early Holocene, the Arnero Sierra was forested and had a relatively warm and humid seasonal climate, indicated in SIR-1 by higher growth rates, lower δ13C and [Mg], and well-developed fluorescent lamination. Similar to other high-resolution stalagmitic records of the Cordillera, from ∼8.5 to 8.0 ka SIR-1 reflects a temporary trend of increasing aridity.
Comparison of the diagenetic and reservoir quality evolution between the anticline crest and flank of an Upper Jurassic carbonate gas reservoir, Abu Dhabi, United Arab Emirates
(Sedimentary Geology, 2018) Morad, Daniel; Nader, Fadi H.; Gasparrini, Marta; Morad, Sadoon; Rossi Nieto, Carlos; Marchionda, Elisabetta; Darmaki, Fatima Al; Martines, Marco; Hellevang, Helge
This petrographic, stable isotopic and fluid inclusion microthermometric study of the Upper Jurassic limestones of an onshore field, Abu Dhabi, United Arab Emirates (UAE) compares diagenesis in flanks and crest of the anticline. The results revealed that the diagenetic and related reservoir quality evolution occurred during three phases, including: (i) eogenesis to mesogenesis 1, during which reservoir quality across the field was either deteriorated or preserved by calcite cementation presumably derived from marine or evolved marine pore waters. Improvement of reservoir quality was due to the formation of micropores by micritization of allochems and creation of moldic/intragranular pores by dissolution of peloids and skeletal fragments. (ii) Obduction of Oman ophiolites and formation of the anticline of the studied field was accompanied by cementation by saddle dolomite and blocky calcite. High homogenization temperatures (125–175 °C) and high salinity (19–26 wt% NaCl eq) of the fluid inclusions, negative δ18OVPDB values (−7.7 to −2.9‰), saddle shape of dolomite, and the presence of exotic cements (i.e. fluorite and sphalerite) suggest that these carbonates were formed by flux of hot basinal brines, probably related to this tectonic compression event. (iii) Mesogenesis 2 during subsidence subsequent to the obduction event, which resulted in extensive stylolitization and cementation by calcite. This calcite cement occluded most of the remaining moldic and inter−/intragranular pores of the flank limestones (water zone) whereas porosity was preserved in the crest. This study contributes to: (1) our understanding of differences in the impact of diagenesis on reservoir quality evolution in flanks and crests of anticlines, i.e. impact of hydrocarbon emplacement on diagenesis, and (2) relating various diagenetic processes to burial history and tectonic events of foreland basins in the Arabian Gulf area and elsewhere.
Diagenesis, provenance and reservoir quality of Triassic TAGI sandstones from Ourhoud field, Berkine (Ghadames) Basin, Algeria
(Marine and Petroleum Geology, 2002) Rossi Nieto, Carlos; Kälin, Otto; Arribas Mocoroa, José; Tortosa, A.
The Triassic TAGI (Trias Argilo-Gréseux Inférieur) fluvial sandstones are the main oil reservoirs in the Berkine Basin, Algeria. Nonetheless, their provenance and diagenesis, and their impact on reservoir quality, are virtually unknown. Samples from the Ourhoud field, representing the Lower, Middle and Upper TAGI subunits, were studied using a combination of petrographic, mineralogical and geochemical techniques. The Lower TAGI sandstones have an average framework composition of Q98.3F0.6R1.1 and 95% of the quartz grains are monocrystalline. By contrast, the Middle–Upper TAGI sandstones have an average framework composition of Q88.3F9.8R1.9 and 79.7% of the quartz grains are monocrystalline. The Lower TAGI quartz arenites derived from Paleozoic siliciclastic rocks, whereas the Middle–Upper TAGI subarkoses originated mainly from metamorphic terrains. This change in provenance is a potential criterion for correlation within the TAGI. Also, this change has contributed to the significantly different diagenetic paths followed by the Lower TAGI quartz arenites and the Middle–Upper TAGI subarkoses. Grain-coating illitic clays are abundant in the Lower TAGI, where they exert a critical control on reservoir quality. These clays are interpreted as pedogenic and/or infiltrated in origin and to have had, in part, smectitic precursors. Shallow burial Fe-dolomite cementation was favored in the downthrown block of the field-bounding fault, where it contributed to the poor reservoir quality. Magnesite–siderite cements are multiphase. The earliest generation is composed of Fe-rich magnesite that precipitated during shallow burial from hypersaline fluids with high Mg/Ca ratios, probably refluxed residual brines associated with the Liassic evaporites. Later magnesite–siderite generations precipitated during deeper burial from waters with progressively higher Fe/Mg ratios. Authigenic vermicular kaolin largely consists of dickite that replaced previously formed kaolinite. Dickitization was followed by late-stage illitization related to the dissolution of detrital and authigenic K-feldspar. Quartz, the most abundant cement, was mainly sourced by the pressure- or clay-induced dissolution of detrital quartz and is a critical factor controlling the reservoir quality. Overall, quartz cement is more abundant in the Lower TAGI than in the Middle–Upper TAGI, and this increase correlates with a decrease in average porosity. Within the Lower TAGI, quartz cement abundance is stratigraphically very variable, which is in part related to facies controlled variations in grain-coating clay, resulting in major vertical variations in reservoir quality. Anhydrite and barite cements postdate quartz overgrowth. The sulfate necessary for their formation was likely sourced by deep subsurface dissolution of Late Triassic–Liassic evaporites.
Chronology of Termination II and the Last Interglacial Period in North Spain based on stable isotope records of stalagmites from Cueva del Cobre (Palencia)
(Journal of iberian geology, 2007) Muñoz García, María Belén; Martín Chivelet, Javier; Rossi Nieto, Carlos; Ford, D.C.; Schwarcz, H.P.
New insight into the timing and structure of the Last Interglacial Period (Eemian) was obtained through U-Th dating of four speleothems from Northern Spain and an analysis of their stable isotope records. The four stalagmites examined were collected from different levels of Cueva del Cobre, a cold high-mountain cave in the Cantabrian Ranges (N Spain), in which speleothem growth took place essentially during the warmer interestadials. Through 18 TIMS and ICPMS datings and 263 stable isotope analyses, the onset of the Eemian interglacial period was precisely dated at 150±2 ka, an age consistent with a few other palaeoclimatic records but notably younger than the age ascribed by the Milankovitch theory. We also date the Eemian–Weichselian transition (~115 ka)for the first time in the Iberian Peninsula. U-Th ages revealed a consistent anomaly at ~105-100 ka BP, which could be related to a drastic environmental change during the MIS-5c interestadial. This event would have caused the resetting of the U-Th system at the base of the stalagmites during a short time interval. In addition, we propose a new simple geochemical test to ensure the lack of disturbance of this type of samples for dating purposes.
Comparación del clima interglacial eemiense y holoceno en el norte de España a partir de los indicadores paleoclimáticos de estalagmitas de la Cueva del Cobre (Palencia)
(Geotemas, 2008) Muñoz García, María Belén; Martín Chivelet, Javier; Rossi Nieto, Carlos; Ford, D.C.; Schwarez, H.P.
El Eemiense se suele considerar un buen análogo del Holoceno a pesar de la diferente configuración orbital de cada época. La comparación de varios indicadores paleoclimáticos obtenidos en estalagmitas eemienses y holocenas de la Cueva del Cobre (Montaña Palentina) aporta datos que permiten verificar esta supuesta similitud. Los indicadores paleoclimáticos comparados son la tasa de crecimiento de las estalagmitas, las texturas de la calcita y los isótopos estables de oxígeno. En comparación con los holocenos, los espeleotemas eemienses son más grandes porque han crecido sin interrupción durante más tiempo, presentan una variedad menor de texturas de calcita y apenas registran láminas anuales. Además, ni las texturas de calcita ni la composición isotópica de oxígeno muestran signos de alteración diagenética. En función de estos indicadores se ha podido deducir que el clima de la zona de estudio fue durante el Eemiense ligeramente más cálido que durante el Holoceno y considerablemente más seco, contradiciendo las estimaciones más aceptadas del clima global para el Último Periodo Interglacial. El clima eemiense en la zona de estudio fue además más estable y tuvo una estacionalidad menos marcada que en los últimos 6000 años. El análisis de los cambios sincrónicos de estos indicadores ha permitido estimar una duración del Último Periodo Interglacial de ~21ka en esta zona.
Composición y procedencia de los sedimentos detríticos del Cretácico Inferior de las subcuencas occidentales de la cuenca del Maestrazgo.
(Geotemas, 2001) Caja Rodríguez, Miguel Ángel; Marfil Pérez, Rafaela; Salas del Mármol, Rafael; Rossi Nieto, Carlos
A thick succession of Lower Cretaceous, predominantly continental clastic sediments ("Weald" facies) crop out in the westernmost sub-basins of the Maestrazgo Basin (eastern Iberian Range, Spain). 62 sandstone samples from the Mora, Castellar, and Camarillas Fms. have been thin sectioned and studied using transmitted-light and scanining electron microscopy, and 4 1 samples were point counted (300-400 points per thin section). The sandstones of the Mora and Castellar Fms. are similar, having mean compositions of QH,FHRh and Q86F10R4, respectively. They are relatively rich in plagioclase and metamorphic rock fragments, lacking K-feldspar. The sandstones of the Camarillas Fm. have mean compositions of Q7gFuR8 (Pehagolosa subbasin) and Q75F,,R, (Calve andAliaga subbasins). They are relatively rich in K-feldspar and, locally, in plutonic rock fragments. In all the studied sandstones, the diagenesis has changed significantly the depositional abundances in feldspar, which is partly dissolved or replaced by kaolin and calcite. The sandstones of the Mora and Castellar Fms. derive in part from low- and medium-grade metamorphic terrains. In contrast, the sandstones of the Camarillas Fm. derive in part from crystalline terrains that were located to the W or NW.
Project number: 280
Aprender ciencia investigando, colaborando y mentorizando, en un entorno interdisciplinar
(2020) Rossi Nieto, Carlos; Ruíz Martínez, Vicente Carlos; García Jiménez, Daniel; Pérez-Soba Aguilar, Cecilia María; Barajas López, María Ascensión; Fernández del Campo, Diana Patricia; Roncero Serrano, Cesar; Martín Cañizares, Esther
Microcodium y trazas fósiles de invertebrados en facies continentales (Paleoceno de la Cuenca de Áger, Lérida)
(Revista de la Sociedad Geológica de España, 1997) Rossi Nieto, Carlos
La sucesión thanetiense (Paleoceno superior) en el valle de Áger (Prepirineo de Lérida) está formada por depósitos continentales y marinos someros y representa en conjunto una secuencia transgresiva formada a su vez por 8 secuencias de orden menor. Las dos secuencias basales están formadas por facies fluviales que pasan hacia techo a depósitos de lagos costeros someros carbonáticos. Las microcoditas son un caso extremo de reemplazamiento de facies fluviales intercanal por Microcodium, y su aparición en la parte superior de las secuencias representa la retracción del sistema fluvial asociada con una subida relativa del nivel del mar. Microcodium se formó en paleosuelos hidromorfos de tipo pseudogley, apareciendo como masas globulares alineadas verticalmente a lo largo de trazas de raíces. Se describen nueve tipos de tubos de excavación de invertebrados. Cinco presentan rellenos activos en menisco y han sido clasificados como Taenidium sp. Los organismos responsables fueron probablemente gusanos oligochaeta acuáticos y terrestres, escarabajos y larvas de insectos. En facies fluviales, los tipos 1 y 2 caracterizan depósitos de crevasse splay y sheetflood; los tipos 3 y 4 caracterizan paleosuelos hidromorfos de tipo pseudogley en la llanura de inundación y son coetáneos con la colonización por Microcodium y con la marmorización; el tipo 5 fue producido por un invertebrado que se alimentaba de Microcodium; el tipo 6 caracteriza facies de canal. En los depósitos de lagos costeros los tipos 7 y 8 están asociados con margas y calizas lacustres someras y el tipo 9 fue originado en condiciones palustres
Limited thermochemical sulfate reduction in hot, anhydritic, sour gas carbonate reservoirs: The Upper Jurassic Arab Formation, United Arab Emirates
(Marine and Petroleum Geology, 2019) Morad, Daniel; Nader, Fadi H.; Morad, Sadoon; Rossi Nieto, Carlos; Gasparrini, Marta; Alsuwaidi, Mohammad; Al Darmaki, Fatima; Hellevang, Helge
Limited thermochemical sulfate reduction (TSR) in hot (130–160°C) and anhydrite-rich sour gas reservoir carbonates of the Arab Formation (Upper Jurassic) is manifested by rare calcitization of anhydrite with slightly lower δ13CVPDB values (−3.2 to −0.1‰) than calcite precipitated in equilibrium with Late Jurassic seawater. Fluid inclusion microthermometry of calcite that has replaced anhydrite indicates that TSR occurred between 130°C and 160°C. The lack of evidence for extensive TSR, despite the suitable current temperatures and abundant sulfates in the gas reservoir, coupled with the relatively more common TSR-related calcite in the flanks (water zone) than crest (gas zone), indicate that: (1) gas emplacement while the reservoir was buried at shallower depth slowed down or inhibited TSR in the crest even when it subsequently reached depths where extensive TSR would occur, and (2) H2S (up to 38 vol%) has migrated from the underlying Permo-Triassic and/or Jurassic sulfate-carbonate deposits. This study demonstrates that constraining the timing of hydrocarbon emplacement within the context of burial-thermal history is crucial for a better understanding of the origin and distribution of H2S in hot, anhydrite-rich, sour gas reservoirs.