A geophysical campaign has been developed along Danco Coast between Py Point to the south, and Vi... more A geophysical campaign has been developed along Danco Coast between Py Point to the south, and Vivot Cape to the north- with the aim of acquire new data to define the geometry, lateral relationships and tectonic development of the geologic units of the Mesozoic magmatic arc exposed in the western border of the Antarctic Peninsula. Rock outcrops mostly belong to
The current tectonic arrangement of Tierra del Fuego and Antarctica is the product of an extensiv... more The current tectonic arrangement of Tierra del Fuego and Antarctica is the product of an extensive and complex evolution that involved the most southern part in South America (SA) from the Early Mesozoic when a subduction area settles down along the Pacific border of Gondwana (GDW) including the then continuous SA and Antarctic Peninsula (AP) (Dalziel and Elliot, 1973; Dalziel,
Within an area of around 119 km2 at Danco Coast (64° 09' SL y 60° 57' WL) a geophysical onshore/o... more Within an area of around 119 km2 at Danco Coast (64° 09' SL y 60° 57' WL) a geophysical onshore/offshore survey was carried out during the 2005-06, 2006-07 and 2008-09 Antarctic summers. The Upper Cretaceous to Tertiary volcanic rocks intruded by a granodioritic pluton which outcrop in coastal areas belongs to the Mesozoic magmatic arc. Leucocratic and melanocratic andesitic dykes hosted in granodiorite at Cierva Cove bear sulphide mineralization. The main structures consist of two fault systems of WNW-ESE and NE-SW orientation which delineate the morphology of onland areas and the shoreline. Our geophysical and geologic survey was directed to acquire new data to define the geometry, lateral relationships and tectonic development of the geologic units of the Mesozoic magmatic arc exposed in the western border of the Antarctic Peninsula (AP). The geologic survey included lithologic and structural sampling, a total of 531 rock cores were obtained for AMS and paleomagnetic studies. The bathymetric survey of Hughes bay (including Sierva and Santucci creeks) has been carried out with the aim of determining the geometric features and spatial distribution of the main submerged depressions and their onshore continuity. This information is very useful for geophysical surveys and for comparing the submerged and emerged morphostructure. The magnetic survey was carried out with two magnetometers of proton free-precession: a Scintrex ENVI GRAD (used as permanent base) and a Geometrics G856 magnetometer employed for sampling stations (which measured the intensity of the total magnetic field and worked synchronized with the base magnetometer in order to make the corresponding corrections). A total of 1670 registrations were acquired in the 5803 GPS fixed onland stations within an area of 2.55 km2. A Zodiac MK3 was employed for the offshore magnetic survey. 11672 stations constitute the magnetic grid in offshore areas, organized along broadly orthogonal sections with a total length of around 548 km. Magnetic susceptibility data (?) were also acquired on outcrops in order to introduce this parameter in the modeling of magnetic anomalies. A Fugro GMS-2 susceptibilimeter was employed at each of the 989 GPS fixed sites in onshore areas. Preliminary processing of acquired data allowed producing an onshore/offshore map of magnetic anomalies which shows maximums (up to 3000 nT) and minimums (-500 nT) organized in parallel NE-SW oriented belts. The correlation of onland geology with the anomaly magnetic map suggests the offshore continuity of outcropping volcanic rocks. The obtained map also indicates the probable extension of volcanic dykes with sulphide mineralization in the Cierva Cove northwards along Danco Coast. The information gained from magnetometric survey combined with ongoing paleomagnetic and petrological work will produce further insights on the geodynamic evolution of NW AP and its relation with other plates of old GDW protoPacific margin.
New multichannel seismic reflection profiles acquired off the Tierra del Fuego Atlantic margin, f... more New multichannel seismic reflection profiles acquired off the Tierra del Fuego Atlantic margin, from the southern part of the Malvinas foreland basin to the inner sector of the Magallanes fold and thrust belt, combined with available commercial profiles and exploration wells, allowed to outline the sedimentary architecture of the foreland basin and the structure of its deformed southern margin. Five
Physics of The Earth and Planetary Interiors, 2002
Paleomagnetic and sedimentological studies carried out on four cores, about 11m long, from the bo... more Paleomagnetic and sedimentological studies carried out on four cores, about 11m long, from the bottom sediments of Escondido Lake (southwestern Argentina) are described. This lake is geologically related to the set of lakes of glacial origin located in western Patagonia.Using several magnetic studies, the predominance of pseudo-single/single domain magnetite as main carrier, as well as an increase of concentration and
Data from paleomagnetic and sedimentological studies carried out on four cores from the bottom se... more Data from paleomagnetic and sedimentological studies carried out on four cores from the bottom sediments of Lake Moreno (southern Argentina) were integrated with data obtained by Creer et al., Geophys. J. R. Astron. Soc., 74 (1983), 109. Within-lake correlations are based on the magnetic susceptibility and intensity of remanent magnetization. The individual measurements were stacked and transformed to a time-scale
Geophysical and geological field surveys carried out in the central and eastern part of the Argen... more Geophysical and geological field surveys carried out in the central and eastern part of the Argentinean Tierra del Fuego Island on the Magallanes–Fagnano fault system (MFS) delineate its main structural features and tectonic setting. Gravity and magnetic data provide critical information for those areas lacking good exposures and support a present-day transtensional tectonic regime for the MFS. In the surveyed area, the MFS segments have a clear morphological expression and are associated with localized gravity minima interpreted as pull-apart basins. In the southeastern corner of Lago Fagnano, the magnetic data suggest a prominent crystalline body in the subsurface, partially exposed in Cerro Hewhoepen. The shape and position of this intrusive body suggest that its emplacement was localized in a releasing bend. Two-dimensional density modeling along a 40 km long N–S section east of Lago Fagnano suggests a deep duplex similar to that exposed in the western part of the island. The obtained model, combined with available surface data, implies the subsurface configuration of geological units and structures, in which the structure of the deep duplex is similar to that exposed in the western part of the Island. The model indicates the southward deepening of the basement from 5 to 7 km and provides further support for the piston shape of the Hewhoepen intrusive.Se ha desarrollado un estudio geofísico y geológico, en la parte central de la Isla de Tierra del Fuego en sector argentino, a través del sistema de Fallas Magallanes–Fagnano (MFS), con el objeto de delinear sus rasgos estructurales y ambiente tectónico. Los datos de gravedad y magnetismo obenidos aportan información crítica para este sector casi totalmente cubierto por sedimentos cuaternarios. Nuestros datos apoyan un modelo tectónico transtensivo para el actual límite de placas representado por el MFS. En el sector estudiado el MFS, tiene una clara expresion morfológica superficial y está asociada con la localización de mínimos gravimétricos, interpretados como cuencas de pull-apart. En la parte SE de la cabecera del Lago Fagnano, los datos de anomalía magnética sugieren la presencia de al menos un cuerpo intrusivo en subsuelo, parcialmente expuesto en el cerro Hewhoepen. Su forma y localización sugieren que se habría emplazado en correspondencia con un área de distensión. Se ha realizado un modelado numérico, utilizando los datos de anomalía de Bouguer, a lo largo de una sección de unos 40 km de largo y 10 km de profundidad, localizada en el extremo Este del Lago Fagnano. El modelo obtenido combinado con nuestros datos geológicos de superficie nos permitieron inferir: (a) la disposición de las diferentes unidades geológicas y continuidad de estructuras principales en subsuelo; (b) la estructura en duplex en profundidad que resulta similar a la expuesta en la parte oeste de la isla; (c) el modelo en profundidad también aporta datos acerca de la profundización hacia el Sur del basamento de 5 a 7 km; y (d) permite caracterizar el intrusivo del Cerro Hewhoepen como un cuerpo cilíndrico.
Antarctic Peninsula's paleogeographic evolution since Gondwana's fragmentation is still... more Antarctic Peninsula's paleogeographic evolution since Gondwana's fragmentation is still a subject of debate. This is so for two main reasons: the fact that the Scotia plate got in the way between the South America and Antarctica plates many millions of years after Gondwana's break-up, destroying the ocean floor's magnetic anomalies between these two plates in the process, and the fact that only a reduced amount of paleomagnetic data exists for Antarctic Peninsula. A thorough paleomagnetic sampling of Cierva Point's Late Jurassic - Early Cretaceous magmatic arc rocks has been carried out, located in the Danco coast northwest of the peninsula (at coordinates 64°09'S and 60°57'W). Remanent magnetization of the samples was studied, along with the magnetic mineralogy and the anisotropy of magnetic susceptibility (AMS). Two paleomagnetic poles were obtained, one of age 150-120 Ma (76.5°S; 49.2°E; dp = 7.6°; dm =8.7°; N = 11) and another one of age 100-90...
A geophysical campaign has been developed along Danco Coast between Py Point to the south, and Vi... more A geophysical campaign has been developed along Danco Coast between Py Point to the south, and Vivot Cape to the north- with the aim of acquire new data to define the geometry, lateral relationships and tectonic development of the geologic units of the Mesozoic magmatic arc exposed in the western border of the Antarctic Peninsula. Rock outcrops mostly belong to
The current tectonic arrangement of Tierra del Fuego and Antarctica is the product of an extensiv... more The current tectonic arrangement of Tierra del Fuego and Antarctica is the product of an extensive and complex evolution that involved the most southern part in South America (SA) from the Early Mesozoic when a subduction area settles down along the Pacific border of Gondwana (GDW) including the then continuous SA and Antarctic Peninsula (AP) (Dalziel and Elliot, 1973; Dalziel,
Within an area of around 119 km2 at Danco Coast (64° 09' SL y 60° 57' WL) a geophysical onshore/o... more Within an area of around 119 km2 at Danco Coast (64° 09' SL y 60° 57' WL) a geophysical onshore/offshore survey was carried out during the 2005-06, 2006-07 and 2008-09 Antarctic summers. The Upper Cretaceous to Tertiary volcanic rocks intruded by a granodioritic pluton which outcrop in coastal areas belongs to the Mesozoic magmatic arc. Leucocratic and melanocratic andesitic dykes hosted in granodiorite at Cierva Cove bear sulphide mineralization. The main structures consist of two fault systems of WNW-ESE and NE-SW orientation which delineate the morphology of onland areas and the shoreline. Our geophysical and geologic survey was directed to acquire new data to define the geometry, lateral relationships and tectonic development of the geologic units of the Mesozoic magmatic arc exposed in the western border of the Antarctic Peninsula (AP). The geologic survey included lithologic and structural sampling, a total of 531 rock cores were obtained for AMS and paleomagnetic studies. The bathymetric survey of Hughes bay (including Sierva and Santucci creeks) has been carried out with the aim of determining the geometric features and spatial distribution of the main submerged depressions and their onshore continuity. This information is very useful for geophysical surveys and for comparing the submerged and emerged morphostructure. The magnetic survey was carried out with two magnetometers of proton free-precession: a Scintrex ENVI GRAD (used as permanent base) and a Geometrics G856 magnetometer employed for sampling stations (which measured the intensity of the total magnetic field and worked synchronized with the base magnetometer in order to make the corresponding corrections). A total of 1670 registrations were acquired in the 5803 GPS fixed onland stations within an area of 2.55 km2. A Zodiac MK3 was employed for the offshore magnetic survey. 11672 stations constitute the magnetic grid in offshore areas, organized along broadly orthogonal sections with a total length of around 548 km. Magnetic susceptibility data (?) were also acquired on outcrops in order to introduce this parameter in the modeling of magnetic anomalies. A Fugro GMS-2 susceptibilimeter was employed at each of the 989 GPS fixed sites in onshore areas. Preliminary processing of acquired data allowed producing an onshore/offshore map of magnetic anomalies which shows maximums (up to 3000 nT) and minimums (-500 nT) organized in parallel NE-SW oriented belts. The correlation of onland geology with the anomaly magnetic map suggests the offshore continuity of outcropping volcanic rocks. The obtained map also indicates the probable extension of volcanic dykes with sulphide mineralization in the Cierva Cove northwards along Danco Coast. The information gained from magnetometric survey combined with ongoing paleomagnetic and petrological work will produce further insights on the geodynamic evolution of NW AP and its relation with other plates of old GDW protoPacific margin.
New multichannel seismic reflection profiles acquired off the Tierra del Fuego Atlantic margin, f... more New multichannel seismic reflection profiles acquired off the Tierra del Fuego Atlantic margin, from the southern part of the Malvinas foreland basin to the inner sector of the Magallanes fold and thrust belt, combined with available commercial profiles and exploration wells, allowed to outline the sedimentary architecture of the foreland basin and the structure of its deformed southern margin. Five
Physics of The Earth and Planetary Interiors, 2002
Paleomagnetic and sedimentological studies carried out on four cores, about 11m long, from the bo... more Paleomagnetic and sedimentological studies carried out on four cores, about 11m long, from the bottom sediments of Escondido Lake (southwestern Argentina) are described. This lake is geologically related to the set of lakes of glacial origin located in western Patagonia.Using several magnetic studies, the predominance of pseudo-single/single domain magnetite as main carrier, as well as an increase of concentration and
Data from paleomagnetic and sedimentological studies carried out on four cores from the bottom se... more Data from paleomagnetic and sedimentological studies carried out on four cores from the bottom sediments of Lake Moreno (southern Argentina) were integrated with data obtained by Creer et al., Geophys. J. R. Astron. Soc., 74 (1983), 109. Within-lake correlations are based on the magnetic susceptibility and intensity of remanent magnetization. The individual measurements were stacked and transformed to a time-scale
Geophysical and geological field surveys carried out in the central and eastern part of the Argen... more Geophysical and geological field surveys carried out in the central and eastern part of the Argentinean Tierra del Fuego Island on the Magallanes–Fagnano fault system (MFS) delineate its main structural features and tectonic setting. Gravity and magnetic data provide critical information for those areas lacking good exposures and support a present-day transtensional tectonic regime for the MFS. In the surveyed area, the MFS segments have a clear morphological expression and are associated with localized gravity minima interpreted as pull-apart basins. In the southeastern corner of Lago Fagnano, the magnetic data suggest a prominent crystalline body in the subsurface, partially exposed in Cerro Hewhoepen. The shape and position of this intrusive body suggest that its emplacement was localized in a releasing bend. Two-dimensional density modeling along a 40 km long N–S section east of Lago Fagnano suggests a deep duplex similar to that exposed in the western part of the island. The obtained model, combined with available surface data, implies the subsurface configuration of geological units and structures, in which the structure of the deep duplex is similar to that exposed in the western part of the Island. The model indicates the southward deepening of the basement from 5 to 7 km and provides further support for the piston shape of the Hewhoepen intrusive.Se ha desarrollado un estudio geofísico y geológico, en la parte central de la Isla de Tierra del Fuego en sector argentino, a través del sistema de Fallas Magallanes–Fagnano (MFS), con el objeto de delinear sus rasgos estructurales y ambiente tectónico. Los datos de gravedad y magnetismo obenidos aportan información crítica para este sector casi totalmente cubierto por sedimentos cuaternarios. Nuestros datos apoyan un modelo tectónico transtensivo para el actual límite de placas representado por el MFS. En el sector estudiado el MFS, tiene una clara expresion morfológica superficial y está asociada con la localización de mínimos gravimétricos, interpretados como cuencas de pull-apart. En la parte SE de la cabecera del Lago Fagnano, los datos de anomalía magnética sugieren la presencia de al menos un cuerpo intrusivo en subsuelo, parcialmente expuesto en el cerro Hewhoepen. Su forma y localización sugieren que se habría emplazado en correspondencia con un área de distensión. Se ha realizado un modelado numérico, utilizando los datos de anomalía de Bouguer, a lo largo de una sección de unos 40 km de largo y 10 km de profundidad, localizada en el extremo Este del Lago Fagnano. El modelo obtenido combinado con nuestros datos geológicos de superficie nos permitieron inferir: (a) la disposición de las diferentes unidades geológicas y continuidad de estructuras principales en subsuelo; (b) la estructura en duplex en profundidad que resulta similar a la expuesta en la parte oeste de la isla; (c) el modelo en profundidad también aporta datos acerca de la profundización hacia el Sur del basamento de 5 a 7 km; y (d) permite caracterizar el intrusivo del Cerro Hewhoepen como un cuerpo cilíndrico.
Antarctic Peninsula's paleogeographic evolution since Gondwana's fragmentation is still... more Antarctic Peninsula's paleogeographic evolution since Gondwana's fragmentation is still a subject of debate. This is so for two main reasons: the fact that the Scotia plate got in the way between the South America and Antarctica plates many millions of years after Gondwana's break-up, destroying the ocean floor's magnetic anomalies between these two plates in the process, and the fact that only a reduced amount of paleomagnetic data exists for Antarctic Peninsula. A thorough paleomagnetic sampling of Cierva Point's Late Jurassic - Early Cretaceous magmatic arc rocks has been carried out, located in the Danco coast northwest of the peninsula (at coordinates 64°09'S and 60°57'W). Remanent magnetization of the samples was studied, along with the magnetic mineralogy and the anisotropy of magnetic susceptibility (AMS). Two paleomagnetic poles were obtained, one of age 150-120 Ma (76.5°S; 49.2°E; dp = 7.6°; dm =8.7°; N = 11) and another one of age 100-90...
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