Biomineralización en el maar laguna Timone, campo volcánico Pali Aike, XII región, Chile
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2018
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es
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Universidad Andrés Bello
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Laguna Timone es un maar del Pleistoceno Inferior inmerso en el Campo Volcánico Pali Aike, ubicado en la Patagonia, al noreste de la ciudad de Punta Arenas. El agua de la laguna corresponde a una salmuera de Na (16700 - 24303 mg/L) -Cl (18785,8 - 29362, 4 mg/L) donde se produce abundante precipitación de carbonato en condiciones ambientales extremas, que incluyen salinidad elevada, temperaturas cercanas a los cero grados y bajas precipitaciones anuales (244 mm).
La gran diversidad de ambientes extremos que existe desde el Norte de Chile hasta la Patagonia incluye ecosistemas biogeológicos que han sido poco explorados. Estos ecosistemas geobiológicos ofrecen sitios de gran interés para realizar investigaciones acerca del origen de la vida en la Tierra. Para entender los procesos que se llevan a cabo en este tipo de sistemas existen dos importantes áreas: La geomicrobiología y la geoquímica microbiana. La primera de éstas se encarga de estudiar el rol que han desempeñado los microorganismos en procesos geológicos mientras que la geoquímica microbiana investiga como la geología influye en el desarrollo de los microorganismos, combinando enfoques geológicos, químicos y biológicos.
Para comprender el origen de los carbonatos (orgánico y/o inorgánico), se realizaron análisis fisicoquímicos del agua mineralogía /composición de sedimentos y petrografía microscópica, Difracción de Rayos X, Microscopía Electrónica de Barrido, estudios microbiológicos e isotópicos de los carbonatos adyacentes a la laguna. Los análisis isotópicos revelaron que en la formación de los carbonatos el control biológico es importante, especialmente para los trombolitos antiguos presentes en la laguna, sin descartar una cantidad no menor de carbonato precipitado inorgánicamente, como sucede para la costra de carbonato. La señal isotópica de δ13C en los depósitos de carbonatos resultó ser una herramienta efectiva para distinguir entre la precipitación inorgánica y la inducida biológicamente, donde los valores negativos de ‰δ13CVPDB (-0.06 - -0.374) son característicos de la precipitación inorgánica, mientras que los valores positivos de ‰δ13CVPDB (0.15 - 5.71) son asociados a la precipitación inducida biológicamente.
El ensayo de precipitación de calcita inducida por microorganismos corroboró la presencia de actividad bacteriana con la precipitación de cristales de calcita, efectuado por la especie Microbacterium sp, cuyo cristal formado tiene una red cristalina distinta a la calcita geológica.
El desarrollo de los carbonatos además se encuentra condicionado por una serie de factores, tales como: la saturación de iones de Ca+2, pH, condiciones ambientales, climáticas e hidrológicas, así como de parámetros petrológicos y texturales basado en la composición mineral, porosidad y permeabilidad del material sedimentario. La concentración Ca+2 disponible se asocia principalmente a: la meteorización de las rocas circundantes; la acumulación de las aguas lluvias, agua saturada que viene de las profundidades, que fluye hacia arriba a través de los sedimentos y a fluidos hidrotermales que ascienden a través de fracturas, los cuales alcanzan la superficie y se mezclan con aguas meteóricas dando origen a fluidos termogénicos caracterizados por valores positivos de δ13C.
Timone Lagoon is a maar in the Lower Pleistocene immersed in the Pali Aike Volcanic Field, located in the Patagonia, northeast of Punta Arenas city. The Timone Lagoon brine waters contain Na (16700 - 24303 mg/L) -Cl (18785,8 - 29362, 4 mg/L) where an abundant precipitation of Carbonate is produced in extreme environmental conditions including high salinity, temperatures close to zero degrees, and low annual precipitation (244 mm). The great extreme environment diversity found from the North of Chile to the Patagonia includes bio-geological ecosystems tat have been barely explored. These geobiologial ecosystems offer sites of great interest to conduct research about the origin of life on Earth.There are two imperative science branches that will help us to better understand the processes that are carried out in this kind of systems: Geo-microbiology and microbial geochemistry. The first is responsible for studying the role that microorganisms have played in geological processes. Microbial geochemistry, on the other hand, investigates how geology influences the development of microorganisms combining geological, chemical and biological approaching. In order to understand the origin of the carbonates, either organic and/or inorganic, a physicochemical water analysis was elaborated. This research examined mineralogy/composition of sediments and microscopic petrography, X-ray diffraction, scanning electron microscopy, microbiological and isotopic studies of adjacent carbonates. The isotopic investigation revealed that in the formation of the carbonate the biological control is important, especially the ancient thrombolites present in the lagoon; without discarding a not less amount of inorganic precipitated carbonate such as the carbonate crust. The δ13C signal in carbonate deposits is an effective tool to distinguish between inorganic and biologically induced precipitation, where negative values of ‰ δ13CVPDB (-0.06 - -0.374) are characteristic of inorganic precipitation, while positive values of ‰ δ13CVPDB (0.15 - 5.71) are characteristic of the biologically induced precipitation. The microbiologically induced calcium carbonate precipitation experiment substantiated the presence of bacterial activity with the precipitation of calcite crystals, made by the Microbacterium sp species, whose developed crystal has a crystalline structure different from geological calcite. The development of carbonates is conditioned by a series of factors, such as: saturation of Ca+2 ions, pH, environmental conditions, climatic and hydrological, as well as petrological and textural parameters such as mineral composition, porosity and permeability of the sedimentary material. The available Ca+2 concentration is associated with: the weathering of the rocks of the surrounding rocks; The accumulation of rainwater and saturated water that comes from the depths, which flows upwards through the sediments and to hydrothermal fluids that ascend through fractures, which reach the surface and mix with meteoric waters, giving rise to thermogenic fluids characterized by positive values of δ13C.
Timone Lagoon is a maar in the Lower Pleistocene immersed in the Pali Aike Volcanic Field, located in the Patagonia, northeast of Punta Arenas city. The Timone Lagoon brine waters contain Na (16700 - 24303 mg/L) -Cl (18785,8 - 29362, 4 mg/L) where an abundant precipitation of Carbonate is produced in extreme environmental conditions including high salinity, temperatures close to zero degrees, and low annual precipitation (244 mm). The great extreme environment diversity found from the North of Chile to the Patagonia includes bio-geological ecosystems tat have been barely explored. These geobiologial ecosystems offer sites of great interest to conduct research about the origin of life on Earth.There are two imperative science branches that will help us to better understand the processes that are carried out in this kind of systems: Geo-microbiology and microbial geochemistry. The first is responsible for studying the role that microorganisms have played in geological processes. Microbial geochemistry, on the other hand, investigates how geology influences the development of microorganisms combining geological, chemical and biological approaching. In order to understand the origin of the carbonates, either organic and/or inorganic, a physicochemical water analysis was elaborated. This research examined mineralogy/composition of sediments and microscopic petrography, X-ray diffraction, scanning electron microscopy, microbiological and isotopic studies of adjacent carbonates. The isotopic investigation revealed that in the formation of the carbonate the biological control is important, especially the ancient thrombolites present in the lagoon; without discarding a not less amount of inorganic precipitated carbonate such as the carbonate crust. The δ13C signal in carbonate deposits is an effective tool to distinguish between inorganic and biologically induced precipitation, where negative values of ‰ δ13CVPDB (-0.06 - -0.374) are characteristic of inorganic precipitation, while positive values of ‰ δ13CVPDB (0.15 - 5.71) are characteristic of the biologically induced precipitation. The microbiologically induced calcium carbonate precipitation experiment substantiated the presence of bacterial activity with the precipitation of calcite crystals, made by the Microbacterium sp species, whose developed crystal has a crystalline structure different from geological calcite. The development of carbonates is conditioned by a series of factors, such as: saturation of Ca+2 ions, pH, environmental conditions, climatic and hydrological, as well as petrological and textural parameters such as mineral composition, porosity and permeability of the sedimentary material. The available Ca+2 concentration is associated with: the weathering of the rocks of the surrounding rocks; The accumulation of rainwater and saturated water that comes from the depths, which flows upwards through the sediments and to hydrothermal fluids that ascend through fractures, which reach the surface and mix with meteoric waters, giving rise to thermogenic fluids characterized by positive values of δ13C.
Notas
Tesis (Geólogo)
proyecto Fondecyt N°1161818, Proyecto LAMIR (UFPR) y Proyecto Bioquímico por la cooperación para poder realizar esta investigación.
proyecto Fondecyt N°1161818, Proyecto LAMIR (UFPR) y Proyecto Bioquímico por la cooperación para poder realizar esta investigación.
Palabras clave
Geomicrobiología, Investigaciones, Chile, Magallanes, Geoquímica