Naturalis

Repositorio institucional de la
Facultad de Ciencias Naturales y Museo de la Universidad Nacional de La Plata

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Autores e Instituciones
La sección de Perfiles de autores e Instituciones reúne a las personas y organizaciones que forman parte de la producción científica disponible en el repositorio. Permite identificar a los investigadores, docentes y equipos de trabajo, así como sus filiaciones institucionales.
Producción Científica
La Producción científica reúne los resultados de investigación generados por los docentes e investigadores de la Facultad de Ciencias Naturales y Museo (UNLP) y Unidades del CONICET. Este espacio incluye artículos en revistas, trabajos en congresos, informes técnicos, tesis y otras contribuciones que reflejan el desarrollo del conocimiento en las distintas disciplinas de las ciencias naturales.
Publicaciones del Museo de La Plata
Las publicaciones del Museo son editadas por el Museo de La Plata desde 1890 hasta la actualidad, con artículos de Antropología, Botánica, Ecología, Geología, Paleontología y Zoología. Comenzaron a publicarse en 1890, de forma casi paralela con Los Anales del Museo. Francisco Pascasio Moreno consideraba que el Museo debía tener sus propias publicaciones constituyéndose como un medio para la difusión de las investigaciones que se realizaban en la institución y sirviendo además como elemento de canje con otros museos, bibliotecas e instituciones del mundo.

Recent Submissions

Phytoliths reveal Paleocene–Eocene forest expansions preceded dryland vegetation in southern South America
(Geological Society of America, 2025-09-12) Stiles, Elena; Canares, Brielle A.D.; Trayler, Robin B.; Ibañez-Mejía, Mauricio; Gelfo, Javier Nicolás; Raigemborn, María Sol; Kohn, Matthew J.; Erra, Georgina; Goin, Francisco Javier; Strömberg, Caroline A. E.
The evolutionary history of lowland southern South American vegetation, particularly during the Paleocene–Eocene, remains enigmatic due to few existing paleobotanical records. Existing vegetation models present contradicting hypotheses ranging from expansive grasslands to tropical forests during this time. Resolving these contradictions is critical for reconstructing the ecological context surrounding the emergence of endemic South American faunas and understanding the relationship between climate and vegetation structure and composition during the warmest interval of the Cenozoic. Here, we present a basin-wide phytolith analysis from Paleocene–Eocene terrestrial deposits in the San Jorge Basin, Argentine Patagonia. These records expand existing phytolith studies and integrate new radiometric dates, providing a temporally resolved view of vegetation dynamics in the early Cenozoic. Phytolith assemblage composition suggests that forests dominated lowland ecosystems during the warm and humid Paleocene to the middle Eocene. Relative palm abundance increased between the middle and late Eocene as lowland humid megathermal forests began transitioning to progressively colder, arid, and more open vegetation, corroborated by existing paleobotanical, geochemical, and faunal records. Grasses were rare and likely represented forest understory elements until at least the early–middle Miocene, contradicting hypotheses of early Cenozoic grassy habitats in South America. Grass abundances increased between the early and middle Miocene alongside the return of humid forests as temperatures and precipitation rose in the region. Sustained cooling and aridification between the middle Miocene and the Quaternary led to the rise of Patagonian steppe vegetation.
A Cretaceous siliceous sinter in NE China: Sedimentological and geochemical constraints on its genesis
(Elsevier BV, 2024-04) You, Yaxian; Wen, Huaguo; Luo, Lianchao; Campbell, Kathleen A.; Guido, Diego Martín; Capezzuoli, Enrico; Lu, Zhipeng; Yang, Yunbao; Wen, Huaguo; Luo, Lianchao
Phanerozoic sinter deposits have been reported globally, with their identification mainly based on sedimentological, petrological, and mineralogical studies. In this study, a detailed geochemical investigation, combined with sedimentological characterization, was conducted on the Wugonglilu siliceous deposit, a Cretaceous (106 Ma) sinter in NE China, to examine its genesis. The deposit is inferred as a siliceous hot spring deposit (sinter) owing to its geological setting in an epithermal gold-mining district, its morphologically variable microbial textures typical of subaerial sinters, and nearly pure silica composition. Three lithofacies were recognized in this study, including laminated to thinly bedded sinter, silica-cemented breccia, and epithermal vein, which represent deposits from three contrasting hydrothermal environments. The 87Sr/86Sr ratios of the sinter are similar to the bedrock through which the geothermal fluids passed, namely the Upper Triassic Dajiahe Formation (T3dj), a marine siliceous rock unit, and the Lower Cretaceous Datashanlinchang Formation (K1d), a rhyolite unit. Results indicate that both underlying units are possible Sr sources of the silica in the Wugonglilu sinter. The REE + Y (rare-earth elements and yttrium) patterns of the sinter exhibit significant variability, primarily due to terrestrial detrital contamination. Differential REE + Y contamination by terrestrial detritus was striking in the white and dark laminae/beds of the laminated to thinly bedded sinter. The white laminae/beds, generally less contaminated, were probably formed during the dry season, whereas the dark laminae/beds exhibiting greater detrital contamination were likely formed during the wet season.When excluding the samples strongly contaminated by detritus, the sinter exhibits Y anomalies comparable to Post-Archean Australian Shale (PAAS), and to the adjacent underlying K1d rhyolite and T3dj siliceous rock samples, indicating that these anomalies were not inherited from rocks dominating the reservoirs. Furthermore, the sinter shows a (Ce/Ce*)N range close to that of the underlying marine siliceous rock and rhyolite samples, reflecting that the (Ce/Ce*)N of the sinter is largely inherited from the reservoir rock(s). The overall REE + Y patterns of the sinter range from nearly flat to LREE-depleted, similar to some samples of the K1d rhyolite and T3dj siliceous rock units. However, most samples of the K1d rhyolite and T3dj siliceous rock display (Pr/Tb)N and (Pr/Yb)N higher than many studied sinter samples. This is likely because of the formation of strong HREE–carbonate complexes during groundwater migration. Based on these results, a generalized formation model of the studied sinter system was constructed. This study suggests that integrated sedimentological and geochemical investigations can aid in interpreting the genesis of sinter deposits, in particular the link between sinter deposits and corresponding reservoir rocks.
Trace metal and organic biosignatures in digitate stromatolites from terrestrial siliceous hot spring deposits: Implications for the exploration of martian life
(Elsevier BV, 2024-09) Nersezova, Ema E.; Rowe, Michael C.; Campbell, Kathleen A.; Langendam, Andrew; Tollemache, Cherie; Lyon, Barbara; Galar, Amanda; Guido, Diego Martín; Teece, Bronwyn L.; Hamilton, Trinity L.
Novel biosignatures of laminated, microbial, digitate sedimentary structures – stromatolites – from modern geothermal fields of the Taup¯o Volcanic Zone, New Zealand, and from El Tatio, Chile, provide an opportunity to investigate evidence of extremophile life preserved in siliceous hot spring deposits, or sinters, interpreted as analogs for early life on Earth and possibly Mars. Synchrotron-μXRF, electron microprobe analysis, Raman spectroscopy, and optical microscopy are used in a coordinated approach to identify corroborating textural and chemical (organic, inorganic) evidence of life in these modern, opaline (amorphous) siliceous materials. Fluid mobile elements, such as As and Sr, track the growth history of the digitate structures. Trace element enrichments of Ca, Al, Ga, +/􀀀 Fe, Mn, As, Rb, Cs, and Sr, are identified in silicified sheaths of microbial filaments embedded within the sinter. In contrast, silicified diatoms in some sinter samples show no trace element enrichment. Gallium enrichments have also been observed in other 16 ka and Jurassic (150 Ma) microbial palisade sinter textures, suggesting the potential for preservation through geologic time, even after recrystallization to quartz. Raman analysis reveals spectra of organics, consistent with pigments for UV protection in cyanobacteria, in silicified sheaths around microbial filaments and are co-located with trace metal enrichments in digitate structures. Due to spectral bands, the location of these molecules (i.e., in the sheaths), and the sampling locations, we ascribe the spectra to scytonemin and carotenoid class molecules. The combined analytical approach outlined here provides a robust means to assess the validity of novel biosignatures, with application to the exploration of Mars, where preservation of opaline silica in >3.6 Ga deposits has the potential to preserve a range of microbial biosignatures.
Paragénesis de la mineralización de la Veta 49, proyecto Calcatreu, Macizo de Somún Cura, Río Negro, Argentina
(Asociación Geológica Argentina, 2024) Wernert, Matías Sebastián; Vera, Dario; Paolini, Marcelo; Jovic, Sebastián Miguel; Guido, Diego Martín
El proyecto Calcatreu es un depósito epitermal de baja sulfuración ubicado en el centro-oeste de la provincia de Río Negro, aproximadamente 60 km al sur de la ciudad de Ingeniero Jacobacci. Presenta múltiples enjambres de vetas de cuarzo-carbonato-adularia, con 746 kOz de recursos indicados y una ley promedio de 2.36 g/t Au Eq. La Veta 49 es uno de los principales cuerpos mineralizados del depósito, y presenta una corrida de 1 km, potencias de entre 3 a 12 m, y vergencia NE-SO con inclinación de 55° a 75° SE. La mineralización ocurrió bajo un régimen estructural extensivo asociado a la Zona de Falla de Gastre, y estuvo controlada por fallamiento normal y procesos de ebullición. Se identificaron 6 estadios hidrotermales para la paragénesis de mineralización: 1) Brechas tectónico-hidrotermales con rellenas por pirita-esmectita-clorita; 2) Carbonatos brechosos monomícticos; 3) Carbonatos bandeados, masivos, y brechosos asociados a vetillas de pirita, calcopirita, esfalerita, galena y eléctrum; 4) Cuarzo bandeado, con ocasionales calcita, adularia y láminas de ginguros conformadas por pirita, calcopirita, galena, esfalerita, tetraedrita-tennantita y eléctrum; 5) Cuarzo masivo, brechoso y bandeado, sin concentraciones de oro y plata, y con ocasional amatista; 6) Carbonatos bandeados, masivos y drusiformes. La mayor parte de las concentraciones de Au-Ag se asocian con ginguros del estadio 4, y están dispuestas como clavos mineralizados de alta ley dentro de la Veta 49. La alteración meteórica abarca una columna oxidada de hasta 90 m, a la cual también se asocian altas leyes de Au-Ag con escasos sulfuros de enriquecimiento secundario.
Wernert, Matías Sebastián