Andrea Coronato | Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Centro Austral de Investigaciones Científicas (CADIC) (original) (raw)
Papers by Andrea Coronato
Vegetation History and Archaeobotany, Jul 18, 2015
Your article is protected by copyright and all rights are held exclusively by Springer-Verlag Ber... more Your article is protected by copyright and all rights are held exclusively by Springer-Verlag Berlin Heidelberg. This e-offprint is for personal use only and shall not be selfarchived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com".
Review of Palaeobotany and Palynology, 2017
Postglacial environments in the southern coast of Lago Fagnano, central Tierra del Fuego, Argenti... more Postglacial environments in the southern coast of Lago Fagnano, central Tierra del Fuego, Argentina, based on pollen and fungal microfossils analyses
Wedge-like structures occur in raised beach gravels near Rio Grande, eastern Tierra Del Fuego (la... more Wedge-like structures occur in raised beach gravels near Rio Grande, eastern Tierra Del Fuego (latitude 53°50′S; longitude 67°5′W). They vary in dimension, being approximately 1.0-1.5 m deep and 0.3-0.8 m in apparent width. Some are closely spaced, while others are as much as 5.0-8.0 m apart. The infill is predominantly fine and coarse sand, together with silt, all of local provenance. There is little evidence of secondary infill. It is unclear whether these structures are soil wedges, sand wedges, or composite wedges. Their significance as regards the possible previous occurrence of perennially-frozen ground in the lowlands of Tierra del Fuego has yet to be determined.
Revista del Museo de La Plata
El objetivo de esta contribución se enfoca en comprender el modo en que los procesos geomorfológi... more El objetivo de esta contribución se enfoca en comprender el modo en que los procesos geomorfológicos inciden en la señal arqueológica y la variabilidad esperable en términos de integridad, resolución y obstrusividad del registro. Se presentan dos casos de contextos arqueológicos vinculados a geoformas frecuentes en el área esteparia del norte de Tierra del Fuego: terrazas lacustres cubiertas por sedimentos eólicos y dunas perched. Se analizan los hallazgos arqueológicos asociados a hoyadas de deflación excavadas en una terraza lacustre en la localidad Tres Marías (53°47´50”S-68°11´59”O) y los sitios YowenKo/Amalia 6 (53°34´40”S-68°25´46”O), vinculados a una duna perched, de la localidad Amalia. Los estudios desarrollados permiten observar que los procesos implicados en la formación del registro en ambos tipos de geoforma llevan a situaciones disimiles de preservación y especialmente de resolución arqueológica. En este sentido, las dunas perched son espacios favorables para la detecc...
Journal of South American Earth Sciences
<p>At 53&#176; S, pans, shallow lakes, lacustrine terraces, perched dunes a... more <p>At 53&#176; S, pans, shallow lakes, lacustrine terraces, perched dunes and paleosols are most of the typical landforms and features of the Fuegian steppe conditioned by climate. They are in a cold, semi-arid, oceanic climate highly affected by the Southern Westerlies winds (SWW).</p><p>During spring and early summer, rainfall, snow melting, and runoff promote the infill of the pans that become in brackish, shallow lakes. When the systems are filled with water, the permanent, high-speed SWW generates waves on the lakes' coasts; whereas the shallow lakes dry up again, bottom sediments are deflated. Wind erosion on the coastal rocky cliffs and deflation contribute to the perched dunes formation.</p><p>Since the Late Glacial, multi centennial wet/dry cycles allowing the development of specific landforms and features are also recorded by proxy studies. During the dry intervals, erosion removed fine sediments from the marine sandstones and limestones cliffs while deflation deepened the dried basins contributing with bottom lake sediments, diatoms and organic matter remnants in the dune deposits. Both processes provide sediments which accumulate on the top of the cliffs forming perched dunes.&#160; Accumulation rates varied through different time intervals allowing the perched dunes to grow and increase their heights, while the spreading of halophytes around the lakes evidence that its area diminished. The algae and ostracod assemblages suggest mesohaline or slightly alkaline conditions, higher conductivity, and enhanced evaporation whereas there was a remarkable change in diatom assemblages from planktonic to common species in terrestrial and dry settings. All these evidences suggest a lowering in lake water levels.&#160;</p><p>Conversely, during the wet intervals, lake water levels were relatively higher and probably deeper than today. Several lacustrine terraces extend around the lake&#8217;s margins more than 10 m above the present lake levels. During these intervals, grasses expanded, and halophytes retracted. The algae and ostracods assemblages indicated freshwater supply, high nutrient loading, oligohaline and deeper water body. At this time, diatom assemblages were more diverse including planktonic species. Also, the presence of sedges and hygrophilous taxa pointed to the development of moist environments surrounding the lake. Dune formation was interrupted and pedogenetic processes occurred on their upper layers until renewed aeolian deposition, a dry cycle, buried them again. Paleosol structures varied over time according to the availability of environmental humidity, with a less developed pedological structure towards the Middle and Late Holocene. These paleosols showed the dominance of local herbaceous and/or shrub vegetation along with the presence of arbuscular mycorrhizal fungi.</p><p>These wet-dry cycles were conditioned by the latitudinal migration of the SWW core. When it migrates northwards, the intensity of winds diminishes and the entrance of humid air masses from the Atlantic is favoured. By the contrary, dry cycles result from the position of the SWW core in latitudes close to 50&#176;S, allowing the wind to reach the region with high speed and frequency, preventing entry of moist air from the Atlantic and promoting a rain-shadow effect in the landscape.</p>
<p>This contribution aims to present a methodology to select, describe and hierarch... more <p>This contribution aims to present a methodology to select, describe and hierarchize cultural georesources in northern Tierra del Fuego (Argentina) in order to encourage geotourism strategies in this touristically underdeveloped area. A cultural georesource refers to a geological or geomorphological site which reveals an archaeological or historical record related to the regional peopling.&#160;</p><p>Based on previous own papers about methodologies to assess geodiversity, an specific approach that adds a cultural viewpoint of georesources is inhere presented.&#160;</p><p>The analysis is based on three axis: geological/geomorphological, cultural and tourist aspects, considering six criteria with four parameters in each case, as follows:</p><ul><li>Geological/geomorphological criteria: available information, preservation degree, singularity, representativeness, didactic interest and degradation risk.&#160;&#160;</li> <li>Cultural criteria: available information, frequency, chronology, preservation degree, vulnerability and didactic interest.</li> <li>Tourist criteria: scenic value, complementarity of natural and cultural elements, current land uses, tourist development strategies, facilities and accessibility.</li> </ul><p>Each criteria is weighted according to a scale from 0 to 3, being 3 the best rated. The sum of the eighteen parameters&#8217; values gives a final score to each cultural georesource.&#160;&#160;</p><p>This methodology was applied on 48 geological or geomorphological sites previously detected, through almost 380 km along coastal and inland roads. 27 of them turned out to be cultural georesources that were afterwards&#160; described, mapped and hierarchized in different landscapes of northern Tierra del Fuego, such as Holocene fluvial, littoral, lacustrine and aeolian environments, Pleistocene moraines and Miocene rocky hills. At the same time, these georesources contain information about different stages of peopling from pedestrian hunters gatherers since 7000 yrs B.P., the European arrival during the XIX<sup>th</sup> century until the settlement of the present economic activities which include cattle rising and oil industry. Besides, most cultural georesources offer no facilities, some of them are not even free to access and just a few, mainly those close to urban areas, are already being used for recreational purposes.&#160;&#160;</p><p>For instance, the best cultural georesource rated in this study is &#8220;R&#237;o Grande estuary&#8221; with 41 points over the maximum of 54. Located close to a main Fuegian city, it is a great example of fluvial-littoral processes and a keystone of recent history. However, it is not included in the current tourist offer but this condition could change taking into account this type of research which draws upon the&#160;educational potential.&#160;&#160;&#160;&#160;</p><p>The methodology proved to be useful as a tool to assess georesources considering their cultural values. This approach allows to deepen the understanding of the local history in terms of natural and cultural processes, since it focuses on the didactic interest of each resource. This may lead to reinforce the local identity as well as to spread Earth and Human Sciences in site sceneries in a more attractive way.&#160;</p>
Revista de la Asociación Geológica Argentina, Sep 15, 2020
Palaeogeography, Palaeoclimatology, Palaeoecology, 2022
Bulletin of the AAS, 2021
Fil: Oria, Jimena. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Austral de ... more Fil: Oria, Jimena. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Austral de Investigaciones Cientificas; Argentina
This chapter highlights different aspects of origin, vegetation development and uses of Tierra de... more This chapter highlights different aspects of origin, vegetation development and uses of Tierra del Fuego and Isla de los Estados peatlands. Most peatlands in the region were formed when the Last Glaciation was ending, during the Late Glacial period (between 19,000 and 11,500 years BP), while the active glaciers were receding. In peatlands, plant communities vary their composition along the time related to climatic and hydrological changes taking place during its formation. These changes are recorded in the succession of plant macro-remains preserved in-situ. According to the dominant species, peatlands of Tierra del Fuego may be classified in three main types: Sphagnum or raised bogs, Astelia or cushion bogs and Carex or sedge fens. Uses of peat deposits are made principally on Sphagnum magellanicum bogs base on its particular properties. Different uses of the peat material can be mentioned: fuel, solid base for leguminosae inoculants, industrial absorbents for oil and hydrocarbons, orchid intensive culture, mushroom casing, aquariums and biofertilizers.
Advances in Geomorphology and Quaternary Studies in Argentina, 2021
Relict sand wedges are ubiquitous in southern Patagonia. At six sites we conducted detailed inves... more Relict sand wedges are ubiquitous in southern Patagonia. At six sites we conducted detailed investigations of stratigraphy, soils, and wedge frequency and characteristics. Some sections contain four or more buried horizons with casts. The cryogenic features are dominantly relict sand wedges with an average depth, maximum apparent width, minimum apparent width, and H/W of 78, 39, 3.8, and 2.9 cm, respectively. The host materials are fine-textured (silt loam, silty clay loam, clay loam) till and the infillings are aeolian sand. The soils are primarily Calciargidic Argixerolls that bear a legacy of climate change. Whereas the sand wedges formed during very cold (-4 to -8 °C or colder) and dry (ca. <=100 mm precipitation/yr) glacial periods, petrocalcic horizons from calcium carbonate contributed by dustfall formed during warmer (7 °C or warmer) and moister (>= 250 mm/yr) interglacial periods. The paleo-argillic (Bt) horizons reflect unusually moist interglacial events where the mean annual precipitation may have been 400 mm/yr. Permafrost was nearly continuous in southern Patagonia during the Illinoian glacial stage (ca. 200 ka), the early to mid-Pleistocene (ca. 800-500 ka), and on two occasions during the early Pleistocene (ca. 1.0-1.1 Ma).
Bulletin of the AAS, 2021
This list includes many of the hundreds of current students and scientists who have made signific... more This list includes many of the hundreds of current students and scientists who have made significant contributions to Mars Polar Science in the past decade. Every name listed represents a person who asked to join the white paper or agreed to be listed and provided some comments.
Bulletin of the AAS, 2021
Quaternary International, 2019
Pull-apart basins are depressions formed at releasing bends or steps in strike-slip fault systems... more Pull-apart basins are depressions formed at releasing bends or steps in strike-slip fault systems, between two parallel vertical strike-slip fault sections. In the present study, the geometry of Udaeta Lake, located in the central section of the Magellan-Fagnano Fault System (MFFS) and previously defined by some authors as a pullapart basin, is analysed. The application of multiple geophysical methods, constrained by surface geological information, enabled us to reveal the subsurface geometry of a section of the MFFS, Udaeta Lake area. Magnetic, gravimetric and detailed topographic profiles, together with vertical electrical soundings were surveyed. The obtained results were compared with fieldwork data. This combined methodology allowed the identification of a transtensional zone with two E-W main sinistral strike-slip faults with a normal component that control the North and South coasts of the lake. This central depression occupied by the lake, with a depth of ∼30 m, is also affected by inferred NE subparallel faults. The geophysical characterization of the MFFS also supports the influence of this fault system on the formation of some water bodies located along the fault zone. Finally, in spite of the lack of detailed geological and structural data, Udaeta Lake we suggest a genesis consistent with a pull-apart basin model. This work constitutes an important contribution to understand earthquake rupture parameters and pattern of surface and in-depth deformation and so, improve knowledge of the seismological behaviour of the MFFS.
Palaeogeography, Palaeoclimatology, Palaeoecology, 2018
Late Holocene environmental conditions are reconstructed from a sedimentary core (LCTF2) retrieve... more Late Holocene environmental conditions are reconstructed from a sedimentary core (LCTF2) retrieved from Laguna Carmen (53° 40' 60''S, 68° 18' 0''W, 29 m a.s.l.) in the Fuegian steppe, northern Tierra del Fuego, southern Argentina. The multiproxy study utilizes pollen/spores, algae, ostracods, palynofacies, Total Organic Carbon (TOC), carbonate content, and lithology. Findings show that grass communities developed over the landscape from 4200 to 1400 cal yr BP. After that, the plant communities fluctuated between grasses to scrubland vegetation. Changes in the lake level as indicated by the halophytes, algal content and ostracod associations, revealed alternation of wet and dry intervals. The palynofacies indicate environments close to the terrestrial source with a great input of terrigenous organic matter into the lake in agree with the sedimentary environment. By comparison with other sites from Tierra del Fuego and southwestern Patagonia, the record of wind-carried Nothofagus pollen is consistent with variations in the Andean forest communities as a consequence of shifts in the latitudinal position and/or strength of the westerlies. The short-term wet/dry intervals seem to be associated with climate events of local occurrence. On the other hand, some wet intervals have been reported in lacustrine records from southern Patagonia. The last millennium showed high environmental variability. Humid conditions characterized the Medieval Climate Anomaly (MCA) event, while dryness conditions were related to the Little Ice Age (LIA) event. In particular this latter interval has been related to a northward migration of the westerlies from their present day focus.
Vegetation History and Archaeobotany, Jul 18, 2015
Your article is protected by copyright and all rights are held exclusively by Springer-Verlag Ber... more Your article is protected by copyright and all rights are held exclusively by Springer-Verlag Berlin Heidelberg. This e-offprint is for personal use only and shall not be selfarchived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com".
Review of Palaeobotany and Palynology, 2017
Postglacial environments in the southern coast of Lago Fagnano, central Tierra del Fuego, Argenti... more Postglacial environments in the southern coast of Lago Fagnano, central Tierra del Fuego, Argentina, based on pollen and fungal microfossils analyses
Wedge-like structures occur in raised beach gravels near Rio Grande, eastern Tierra Del Fuego (la... more Wedge-like structures occur in raised beach gravels near Rio Grande, eastern Tierra Del Fuego (latitude 53°50′S; longitude 67°5′W). They vary in dimension, being approximately 1.0-1.5 m deep and 0.3-0.8 m in apparent width. Some are closely spaced, while others are as much as 5.0-8.0 m apart. The infill is predominantly fine and coarse sand, together with silt, all of local provenance. There is little evidence of secondary infill. It is unclear whether these structures are soil wedges, sand wedges, or composite wedges. Their significance as regards the possible previous occurrence of perennially-frozen ground in the lowlands of Tierra del Fuego has yet to be determined.
Revista del Museo de La Plata
El objetivo de esta contribución se enfoca en comprender el modo en que los procesos geomorfológi... more El objetivo de esta contribución se enfoca en comprender el modo en que los procesos geomorfológicos inciden en la señal arqueológica y la variabilidad esperable en términos de integridad, resolución y obstrusividad del registro. Se presentan dos casos de contextos arqueológicos vinculados a geoformas frecuentes en el área esteparia del norte de Tierra del Fuego: terrazas lacustres cubiertas por sedimentos eólicos y dunas perched. Se analizan los hallazgos arqueológicos asociados a hoyadas de deflación excavadas en una terraza lacustre en la localidad Tres Marías (53°47´50”S-68°11´59”O) y los sitios YowenKo/Amalia 6 (53°34´40”S-68°25´46”O), vinculados a una duna perched, de la localidad Amalia. Los estudios desarrollados permiten observar que los procesos implicados en la formación del registro en ambos tipos de geoforma llevan a situaciones disimiles de preservación y especialmente de resolución arqueológica. En este sentido, las dunas perched son espacios favorables para la detecc...
Journal of South American Earth Sciences
<p>At 53&#176; S, pans, shallow lakes, lacustrine terraces, perched dunes a... more <p>At 53&#176; S, pans, shallow lakes, lacustrine terraces, perched dunes and paleosols are most of the typical landforms and features of the Fuegian steppe conditioned by climate. They are in a cold, semi-arid, oceanic climate highly affected by the Southern Westerlies winds (SWW).</p><p>During spring and early summer, rainfall, snow melting, and runoff promote the infill of the pans that become in brackish, shallow lakes. When the systems are filled with water, the permanent, high-speed SWW generates waves on the lakes' coasts; whereas the shallow lakes dry up again, bottom sediments are deflated. Wind erosion on the coastal rocky cliffs and deflation contribute to the perched dunes formation.</p><p>Since the Late Glacial, multi centennial wet/dry cycles allowing the development of specific landforms and features are also recorded by proxy studies. During the dry intervals, erosion removed fine sediments from the marine sandstones and limestones cliffs while deflation deepened the dried basins contributing with bottom lake sediments, diatoms and organic matter remnants in the dune deposits. Both processes provide sediments which accumulate on the top of the cliffs forming perched dunes.&#160; Accumulation rates varied through different time intervals allowing the perched dunes to grow and increase their heights, while the spreading of halophytes around the lakes evidence that its area diminished. The algae and ostracod assemblages suggest mesohaline or slightly alkaline conditions, higher conductivity, and enhanced evaporation whereas there was a remarkable change in diatom assemblages from planktonic to common species in terrestrial and dry settings. All these evidences suggest a lowering in lake water levels.&#160;</p><p>Conversely, during the wet intervals, lake water levels were relatively higher and probably deeper than today. Several lacustrine terraces extend around the lake&#8217;s margins more than 10 m above the present lake levels. During these intervals, grasses expanded, and halophytes retracted. The algae and ostracods assemblages indicated freshwater supply, high nutrient loading, oligohaline and deeper water body. At this time, diatom assemblages were more diverse including planktonic species. Also, the presence of sedges and hygrophilous taxa pointed to the development of moist environments surrounding the lake. Dune formation was interrupted and pedogenetic processes occurred on their upper layers until renewed aeolian deposition, a dry cycle, buried them again. Paleosol structures varied over time according to the availability of environmental humidity, with a less developed pedological structure towards the Middle and Late Holocene. These paleosols showed the dominance of local herbaceous and/or shrub vegetation along with the presence of arbuscular mycorrhizal fungi.</p><p>These wet-dry cycles were conditioned by the latitudinal migration of the SWW core. When it migrates northwards, the intensity of winds diminishes and the entrance of humid air masses from the Atlantic is favoured. By the contrary, dry cycles result from the position of the SWW core in latitudes close to 50&#176;S, allowing the wind to reach the region with high speed and frequency, preventing entry of moist air from the Atlantic and promoting a rain-shadow effect in the landscape.</p>
<p>This contribution aims to present a methodology to select, describe and hierarch... more <p>This contribution aims to present a methodology to select, describe and hierarchize cultural georesources in northern Tierra del Fuego (Argentina) in order to encourage geotourism strategies in this touristically underdeveloped area. A cultural georesource refers to a geological or geomorphological site which reveals an archaeological or historical record related to the regional peopling.&#160;</p><p>Based on previous own papers about methodologies to assess geodiversity, an specific approach that adds a cultural viewpoint of georesources is inhere presented.&#160;</p><p>The analysis is based on three axis: geological/geomorphological, cultural and tourist aspects, considering six criteria with four parameters in each case, as follows:</p><ul><li>Geological/geomorphological criteria: available information, preservation degree, singularity, representativeness, didactic interest and degradation risk.&#160;&#160;</li> <li>Cultural criteria: available information, frequency, chronology, preservation degree, vulnerability and didactic interest.</li> <li>Tourist criteria: scenic value, complementarity of natural and cultural elements, current land uses, tourist development strategies, facilities and accessibility.</li> </ul><p>Each criteria is weighted according to a scale from 0 to 3, being 3 the best rated. The sum of the eighteen parameters&#8217; values gives a final score to each cultural georesource.&#160;&#160;</p><p>This methodology was applied on 48 geological or geomorphological sites previously detected, through almost 380 km along coastal and inland roads. 27 of them turned out to be cultural georesources that were afterwards&#160; described, mapped and hierarchized in different landscapes of northern Tierra del Fuego, such as Holocene fluvial, littoral, lacustrine and aeolian environments, Pleistocene moraines and Miocene rocky hills. At the same time, these georesources contain information about different stages of peopling from pedestrian hunters gatherers since 7000 yrs B.P., the European arrival during the XIX<sup>th</sup> century until the settlement of the present economic activities which include cattle rising and oil industry. Besides, most cultural georesources offer no facilities, some of them are not even free to access and just a few, mainly those close to urban areas, are already being used for recreational purposes.&#160;&#160;</p><p>For instance, the best cultural georesource rated in this study is &#8220;R&#237;o Grande estuary&#8221; with 41 points over the maximum of 54. Located close to a main Fuegian city, it is a great example of fluvial-littoral processes and a keystone of recent history. However, it is not included in the current tourist offer but this condition could change taking into account this type of research which draws upon the&#160;educational potential.&#160;&#160;&#160;&#160;</p><p>The methodology proved to be useful as a tool to assess georesources considering their cultural values. This approach allows to deepen the understanding of the local history in terms of natural and cultural processes, since it focuses on the didactic interest of each resource. This may lead to reinforce the local identity as well as to spread Earth and Human Sciences in site sceneries in a more attractive way.&#160;</p>
Revista de la Asociación Geológica Argentina, Sep 15, 2020
Palaeogeography, Palaeoclimatology, Palaeoecology, 2022
Bulletin of the AAS, 2021
Fil: Oria, Jimena. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Austral de ... more Fil: Oria, Jimena. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Austral de Investigaciones Cientificas; Argentina
This chapter highlights different aspects of origin, vegetation development and uses of Tierra de... more This chapter highlights different aspects of origin, vegetation development and uses of Tierra del Fuego and Isla de los Estados peatlands. Most peatlands in the region were formed when the Last Glaciation was ending, during the Late Glacial period (between 19,000 and 11,500 years BP), while the active glaciers were receding. In peatlands, plant communities vary their composition along the time related to climatic and hydrological changes taking place during its formation. These changes are recorded in the succession of plant macro-remains preserved in-situ. According to the dominant species, peatlands of Tierra del Fuego may be classified in three main types: Sphagnum or raised bogs, Astelia or cushion bogs and Carex or sedge fens. Uses of peat deposits are made principally on Sphagnum magellanicum bogs base on its particular properties. Different uses of the peat material can be mentioned: fuel, solid base for leguminosae inoculants, industrial absorbents for oil and hydrocarbons, orchid intensive culture, mushroom casing, aquariums and biofertilizers.
Advances in Geomorphology and Quaternary Studies in Argentina, 2021
Relict sand wedges are ubiquitous in southern Patagonia. At six sites we conducted detailed inves... more Relict sand wedges are ubiquitous in southern Patagonia. At six sites we conducted detailed investigations of stratigraphy, soils, and wedge frequency and characteristics. Some sections contain four or more buried horizons with casts. The cryogenic features are dominantly relict sand wedges with an average depth, maximum apparent width, minimum apparent width, and H/W of 78, 39, 3.8, and 2.9 cm, respectively. The host materials are fine-textured (silt loam, silty clay loam, clay loam) till and the infillings are aeolian sand. The soils are primarily Calciargidic Argixerolls that bear a legacy of climate change. Whereas the sand wedges formed during very cold (-4 to -8 °C or colder) and dry (ca. <=100 mm precipitation/yr) glacial periods, petrocalcic horizons from calcium carbonate contributed by dustfall formed during warmer (7 °C or warmer) and moister (>= 250 mm/yr) interglacial periods. The paleo-argillic (Bt) horizons reflect unusually moist interglacial events where the mean annual precipitation may have been 400 mm/yr. Permafrost was nearly continuous in southern Patagonia during the Illinoian glacial stage (ca. 200 ka), the early to mid-Pleistocene (ca. 800-500 ka), and on two occasions during the early Pleistocene (ca. 1.0-1.1 Ma).
Bulletin of the AAS, 2021
This list includes many of the hundreds of current students and scientists who have made signific... more This list includes many of the hundreds of current students and scientists who have made significant contributions to Mars Polar Science in the past decade. Every name listed represents a person who asked to join the white paper or agreed to be listed and provided some comments.
Bulletin of the AAS, 2021
Quaternary International, 2019
Pull-apart basins are depressions formed at releasing bends or steps in strike-slip fault systems... more Pull-apart basins are depressions formed at releasing bends or steps in strike-slip fault systems, between two parallel vertical strike-slip fault sections. In the present study, the geometry of Udaeta Lake, located in the central section of the Magellan-Fagnano Fault System (MFFS) and previously defined by some authors as a pullapart basin, is analysed. The application of multiple geophysical methods, constrained by surface geological information, enabled us to reveal the subsurface geometry of a section of the MFFS, Udaeta Lake area. Magnetic, gravimetric and detailed topographic profiles, together with vertical electrical soundings were surveyed. The obtained results were compared with fieldwork data. This combined methodology allowed the identification of a transtensional zone with two E-W main sinistral strike-slip faults with a normal component that control the North and South coasts of the lake. This central depression occupied by the lake, with a depth of ∼30 m, is also affected by inferred NE subparallel faults. The geophysical characterization of the MFFS also supports the influence of this fault system on the formation of some water bodies located along the fault zone. Finally, in spite of the lack of detailed geological and structural data, Udaeta Lake we suggest a genesis consistent with a pull-apart basin model. This work constitutes an important contribution to understand earthquake rupture parameters and pattern of surface and in-depth deformation and so, improve knowledge of the seismological behaviour of the MFFS.
Palaeogeography, Palaeoclimatology, Palaeoecology, 2018
Late Holocene environmental conditions are reconstructed from a sedimentary core (LCTF2) retrieve... more Late Holocene environmental conditions are reconstructed from a sedimentary core (LCTF2) retrieved from Laguna Carmen (53° 40' 60''S, 68° 18' 0''W, 29 m a.s.l.) in the Fuegian steppe, northern Tierra del Fuego, southern Argentina. The multiproxy study utilizes pollen/spores, algae, ostracods, palynofacies, Total Organic Carbon (TOC), carbonate content, and lithology. Findings show that grass communities developed over the landscape from 4200 to 1400 cal yr BP. After that, the plant communities fluctuated between grasses to scrubland vegetation. Changes in the lake level as indicated by the halophytes, algal content and ostracod associations, revealed alternation of wet and dry intervals. The palynofacies indicate environments close to the terrestrial source with a great input of terrigenous organic matter into the lake in agree with the sedimentary environment. By comparison with other sites from Tierra del Fuego and southwestern Patagonia, the record of wind-carried Nothofagus pollen is consistent with variations in the Andean forest communities as a consequence of shifts in the latitudinal position and/or strength of the westerlies. The short-term wet/dry intervals seem to be associated with climate events of local occurrence. On the other hand, some wet intervals have been reported in lacustrine records from southern Patagonia. The last millennium showed high environmental variability. Humid conditions characterized the Medieval Climate Anomaly (MCA) event, while dryness conditions were related to the Little Ice Age (LIA) event. In particular this latter interval has been related to a northward migration of the westerlies from their present day focus.