Diego Guido - Academia.edu (original) (raw)
Papers by Diego Guido
Revista de la …, 2004
RESUMEN. Se presentan nuevos afloramientos de cuerpos subvolcánicos correlacionables con la Forma... more RESUMEN. Se presentan nuevos afloramientos de cuerpos subvolcánicos correlacionables con la Formación Cerro León en el sector oriental del Macizo del Deseado. Esta unidad aflora en dos sectores, en el bajo Leonardo y en el afloramiento Bahía Laura del Complejo Río ...
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Revista de la Asociación Geológica Argentina, Jun 30, 2019
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ABSTRACT We describe a new Middle-Late Jurassic flora from the La Matilde Formation (Bahia Laura ... more ABSTRACT We describe a new Middle-Late Jurassic flora from the La Matilde Formation (Bahia Laura Group) associated with the San Agustín hot-spring deposit, western Deseado Massif, Southern Patagonia, Argentina. The 7 genera and 14 morphospecies, preserved as impressions, record a relatively diverse woodland plant community dominated by conifers and bennettitaleans growing adjacent to herbaceous lake margin communities.
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American Journal of Botany, 2011
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Journal of South American Earth Sciences, Apr 1, 2021
Abstract A new cyanobacterium, Patagonifilum jurassicum nov. gen. et sp., is structurally preserv... more Abstract A new cyanobacterium, Patagonifilum jurassicum nov. gen. et sp., is structurally preserved in Late Jurassic hydrothermally influenced siliceous chert from the Deseado Massif, Patagonia, Argentina. The cyanobacterium occurs in the form of loosely to densely spaced, heteropolar filaments (up to 4.5 μm wide) that form turf-like stands, or spherical to hemispherical colonies on different substrates, usually degraded plant stems. Filaments consist of barrel-shaped cells enveloped in a non-stratified sheath, and basal cells that are distinct. The fossil is similar to certain present-day members of the Oscillatoriales (e.g., Homoeothrix), Synechococcales (e.g., Tapinothrix), and Nostocales (e.g., Rivularia, Gloeotrichia). Associated with the cyanobacteria are spheroidal to ovoid vesicles, up to 45 μm in diameter, which occur singly or clustered, mostly near the base of the filaments. They resemble certain present-day zoosporic fungi, and algae, coccoid cyanobacteria, and possibly certain arthropod eggs; however, their systematic affinities remain unresolved. This discovery is nevertheless important because it suggests that the cyanobacterial overgrowths from the Patagonian Jurassic cherts were not monospecific, but rather comprised different organisms that perhaps even interacted with each other.
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Journal of South American Earth Sciences, Jun 1, 2020
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International Journal of Plant Sciences, Feb 1, 2020
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Palaeogeography, Palaeoclimatology, Palaeoecology, 2019
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Transactions, Aug 1, 2002
Abstract A well-preserved Jurassic siliceous sinter has been identified at La Marciana farm in so... more Abstract A well-preserved Jurassic siliceous sinter has been identified at La Marciana farm in southern Patagonia, Argentina. Fossil sinters are a rare occurrence and this example bridges the gap between Devonian/Carboniferous examples and more abundant Tertiary sinters. Its presence is significant in the context of exploration for epithermal precious-metal deposits in the Deseado Massif geological province of southern Patagonia. Field and textural characteristics of the La Marciana siliceous deposit provide unequivocal evidence of its origin. It is located in an appropriate volcanic and epithermal environment and it displays a strongly developed non-planar depositional lamination, elongate cavities parallel to this lamination, small-scale stromatolitic columnar structures, moulds of stems and roots of plants and desiccation cracks. Geochemical and oxygen isotope studies provide additional information compatible with a sinter origin. The content of precious-metal elements—apart from in anomalous hydrothermal breccia—is low, and the average Au, Ag, As and Sb concentrations are similar to those of most known fossil sinters. The 18O SMOW values obtained on La Marciana sinter range from 7.3 to 16‰ and could indicate a lower temperature of formation when compared with quartz-vein isotope data from the Cerro Vanguardia area—the best-known example of an epithermal precious-metal deposit in the Deseado Massif. Hydrothermal alteration of the volcanic rocks and the presence of quartz veinlets and hydrothermal breccias with Au and Ag anomalies in the La Marciana area are indicative of gold- and silver-rich hydrothermal activity. Taken in conjunction with the presence of the La Marciana sinter, which is further evidence of Jurassic hot-spring deposits in the western border of the Deseado Massif, this suggests that exploration in the area should focus on locating epithermal quartz vein systems that may be preserved at depth.
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Goldschmidt2022 abstracts, 2022
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Revista de la Asociación Geológica Argentina, Jul 25, 2020
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Geologica Acta, 2014
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Springer eBooks, 2005
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Organic Geochemistry
Gas chromatography-mass spectrometry was applied to samples collected from an exceptionally well-... more Gas chromatography-mass spectrometry was applied to samples collected from an exceptionally well-preserved Late Jurassic (~150 Ma) sinter complex of the Claudia palaeo-geothermal field, Deseado Massif geological province, Argentinean Patagonia, which, despite its age, has never been deeply buried. Results indicate that the distal sinter apron has a much higher preservation potential for indigenous organic matter (OM) than the more proximal (vent area) facies of this palaeo-geothermal field. Specifically, homohopane ratios show that the OM of the proximal apron is of mixed thermal maturities and is in low abundance. In contrast, the OM extracted from the distal apron contains highly abundant, thermally immature biomarkers, the presence of which are consistent with the lower original fluid temperatures of the distal spring facies. Moreover, despite indications of the presence of some thermally mature aromatic compounds, hopane and sterane ratios confirm that the distal apron samples are extremely thermally immature and thereby constitute an area of exceptional molecular preservation. From an astrobiological viewpoint, these results suggest that silica sinter can preserve abundant organics over millions of years in palaeoenvironmentally conducive settings, and that sample-site selection within a hot spring facies-model framework may be critical in the successful search for ancient extra-terrestrial life.
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EPSC-DPS Joint Meeting 2019, Sep 1, 2019
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Journal of South American Earth Sciences, 2021
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Journal of Volcanology and Geothermal Research, 2018
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Revista de la …, 2004
RESUMEN. Se presentan nuevos afloramientos de cuerpos subvolcánicos correlacionables con la Forma... more RESUMEN. Se presentan nuevos afloramientos de cuerpos subvolcánicos correlacionables con la Formación Cerro León en el sector oriental del Macizo del Deseado. Esta unidad aflora en dos sectores, en el bajo Leonardo y en el afloramiento Bahía Laura del Complejo Río ...
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Revista de la Asociación Geológica Argentina, Jun 30, 2019
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Bookmarks Related papers MentionsView impact
ABSTRACT We describe a new Middle-Late Jurassic flora from the La Matilde Formation (Bahia Laura ... more ABSTRACT We describe a new Middle-Late Jurassic flora from the La Matilde Formation (Bahia Laura Group) associated with the San Agustín hot-spring deposit, western Deseado Massif, Southern Patagonia, Argentina. The 7 genera and 14 morphospecies, preserved as impressions, record a relatively diverse woodland plant community dominated by conifers and bennettitaleans growing adjacent to herbaceous lake margin communities.
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American Journal of Botany, 2011
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Journal of South American Earth Sciences, Apr 1, 2021
Abstract A new cyanobacterium, Patagonifilum jurassicum nov. gen. et sp., is structurally preserv... more Abstract A new cyanobacterium, Patagonifilum jurassicum nov. gen. et sp., is structurally preserved in Late Jurassic hydrothermally influenced siliceous chert from the Deseado Massif, Patagonia, Argentina. The cyanobacterium occurs in the form of loosely to densely spaced, heteropolar filaments (up to 4.5 μm wide) that form turf-like stands, or spherical to hemispherical colonies on different substrates, usually degraded plant stems. Filaments consist of barrel-shaped cells enveloped in a non-stratified sheath, and basal cells that are distinct. The fossil is similar to certain present-day members of the Oscillatoriales (e.g., Homoeothrix), Synechococcales (e.g., Tapinothrix), and Nostocales (e.g., Rivularia, Gloeotrichia). Associated with the cyanobacteria are spheroidal to ovoid vesicles, up to 45 μm in diameter, which occur singly or clustered, mostly near the base of the filaments. They resemble certain present-day zoosporic fungi, and algae, coccoid cyanobacteria, and possibly certain arthropod eggs; however, their systematic affinities remain unresolved. This discovery is nevertheless important because it suggests that the cyanobacterial overgrowths from the Patagonian Jurassic cherts were not monospecific, but rather comprised different organisms that perhaps even interacted with each other.
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Journal of South American Earth Sciences, Jun 1, 2020
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International Journal of Plant Sciences, Feb 1, 2020
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Palaeogeography, Palaeoclimatology, Palaeoecology, 2019
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Transactions, Aug 1, 2002
Abstract A well-preserved Jurassic siliceous sinter has been identified at La Marciana farm in so... more Abstract A well-preserved Jurassic siliceous sinter has been identified at La Marciana farm in southern Patagonia, Argentina. Fossil sinters are a rare occurrence and this example bridges the gap between Devonian/Carboniferous examples and more abundant Tertiary sinters. Its presence is significant in the context of exploration for epithermal precious-metal deposits in the Deseado Massif geological province of southern Patagonia. Field and textural characteristics of the La Marciana siliceous deposit provide unequivocal evidence of its origin. It is located in an appropriate volcanic and epithermal environment and it displays a strongly developed non-planar depositional lamination, elongate cavities parallel to this lamination, small-scale stromatolitic columnar structures, moulds of stems and roots of plants and desiccation cracks. Geochemical and oxygen isotope studies provide additional information compatible with a sinter origin. The content of precious-metal elements—apart from in anomalous hydrothermal breccia—is low, and the average Au, Ag, As and Sb concentrations are similar to those of most known fossil sinters. The 18O SMOW values obtained on La Marciana sinter range from 7.3 to 16‰ and could indicate a lower temperature of formation when compared with quartz-vein isotope data from the Cerro Vanguardia area—the best-known example of an epithermal precious-metal deposit in the Deseado Massif. Hydrothermal alteration of the volcanic rocks and the presence of quartz veinlets and hydrothermal breccias with Au and Ag anomalies in the La Marciana area are indicative of gold- and silver-rich hydrothermal activity. Taken in conjunction with the presence of the La Marciana sinter, which is further evidence of Jurassic hot-spring deposits in the western border of the Deseado Massif, this suggests that exploration in the area should focus on locating epithermal quartz vein systems that may be preserved at depth.
Bookmarks Related papers MentionsView impact
Goldschmidt2022 abstracts, 2022
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Revista de la Asociación Geológica Argentina, Jul 25, 2020
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Geologica Acta, 2014
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Springer eBooks, 2005
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Organic Geochemistry
Gas chromatography-mass spectrometry was applied to samples collected from an exceptionally well-... more Gas chromatography-mass spectrometry was applied to samples collected from an exceptionally well-preserved Late Jurassic (~150 Ma) sinter complex of the Claudia palaeo-geothermal field, Deseado Massif geological province, Argentinean Patagonia, which, despite its age, has never been deeply buried. Results indicate that the distal sinter apron has a much higher preservation potential for indigenous organic matter (OM) than the more proximal (vent area) facies of this palaeo-geothermal field. Specifically, homohopane ratios show that the OM of the proximal apron is of mixed thermal maturities and is in low abundance. In contrast, the OM extracted from the distal apron contains highly abundant, thermally immature biomarkers, the presence of which are consistent with the lower original fluid temperatures of the distal spring facies. Moreover, despite indications of the presence of some thermally mature aromatic compounds, hopane and sterane ratios confirm that the distal apron samples are extremely thermally immature and thereby constitute an area of exceptional molecular preservation. From an astrobiological viewpoint, these results suggest that silica sinter can preserve abundant organics over millions of years in palaeoenvironmentally conducive settings, and that sample-site selection within a hot spring facies-model framework may be critical in the successful search for ancient extra-terrestrial life.
Bookmarks Related papers MentionsView impact
EPSC-DPS Joint Meeting 2019, Sep 1, 2019
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Journal of South American Earth Sciences, 2021
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Journal of Volcanology and Geothermal Research, 2018
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