scholarly journals Petrologia das Rochas Vulcânicas da Península Fildes, Ilha Rei George, Antártica

1998 ◽  
Vol 25 (1) ◽  
pp. 35 ◽  
Author(s):  
ADRIANE MACHADO ◽  
FARID CHEMALE JUNIOR ◽  
EVANDRO FERNANDES DE LIMA ◽  
ANA MARIA GRACIANO FIGUEIREDO
Keyword(s):  
Continental Crust ◽  
Volcanic Activity ◽  
Mantle Source ◽  
Mineral Chemistry ◽  
South Shetland Islands ◽  
Magmatic Activity ◽  
Calcic Plagioclase ◽  
Fildes Peninsula ◽  
Shetland Islands ◽  
Basic Rocks

The Paleocene-Eocene volcanic activity in the Fildes Peninsula is marked by basaltic to basalt-andesitic lavas and dykes with subordinate amounts of dacites and rhyolites. Studies of mineral chemistry point to calcic plagioclase (An72-95) and augitic pyroxene phenocrysts and seldom grains of pigeonite and bronzite. Rock chemistry of ten samples indicates a calk-alkaline affinity based on enrichment in LILE and LREE, moderate contens of Zr, negative anomalies of Nb and Ti in multicationic diagrams, the high Al2O3 contents and also because CaO≥FeOT. High contents of FeOT and limited enrichment of SiO2 are caused by fractionation of mafic silicates which probably occurred without cogenetic Ti-magnetite crystallization. The low content of Ni, Cr, Co and MgO in the basic rocks also support this hypothesis. 87Sr/Sr86 initial rations from 0.7033 to 0.7037 and ƐNd positive values (t=55 Ma) of 6.52 and 6.72 suggest a mantle source with few or without assimilation of continental crust. This magmatic activity is thus related to the Mesozoic and Cenozoic subduction in the Antartic region which gave rise to the island arc of the South Shetland Islands.

Aulacoseira glubokoyensis sp. nov. (Bacillariophyceae), a new centric diatom from the Maritime Antarctic region

Phytotaxa ◽  
2017 ◽  
Vol 328 (2) ◽  
pp. 149
Author(s):  
ANNA BEATRIZ JONES OAQUIM ◽  
GLEYCI A.O. MOSER ◽  
HEITOR EVANGELISTA ◽  
MARCUS VINÍCIUS LICÍNIO ◽  
BART VAN DE VIJVER
Keyword(s):  
Dendritic Spines ◽  
South Shetland Islands ◽  
Similar Species ◽  
Centric Diatom ◽  
King George Island ◽  
Maritime Antarctic ◽  
Antarctic Region ◽  
Fildes Peninsula ◽  
Shetland Islands ◽  
Scanning Electron

A new centric diatom, Aulacoseira glubokoyensis sp. nov., is described from the Maritime Antarctic region. The morphology of the species is illustrated using detailed light and scanning electron microscopy observations. Its main discriminating features include the presence of typical irregularly shaped dendritic spines, at least two rimoportulae, marginal striae on the discus and a very large Ringleiste. The new species is compared to similar species worldwide. Aulacoseira glubokoyensis has only been observed in a sediment core taken from Profound Lake on the Fildes Peninsula (King George Island, South Shetland Islands).

scholarly journals Geomorphology and landforms distribution in selected ice-free areas in the South Shetland Islands, Antarctic Northern Peninsula region

2016 ◽  
Vol 42 (2) ◽  
pp. 435 ◽  
Author(s):  
J. López-Martínez ◽  
T. Schmid ◽  
E. Serrano ◽  
S. Mink ◽  
A. Nieto ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Environmental Changes ◽  
Weather Conditions ◽  
South Shetland Islands ◽  
The South ◽  
Fildes Peninsula ◽  
Shetland Islands ◽  
Highly Sensitive ◽  
Remote Sensing Techniques ◽  
Maxwell Bay

Ice-free areas cover a small percentage of the land in the South Shetland Islands. However, they are significant as they contain ecosystems highly sensitive to environmental changes and are located within a region affected by global warming. These areas are dominated by periglacial, glacial, fluvial, and coastal processes and landforms, where permafrost is often present. Soil development is observed although vegetation cover is sparse and closely related to the geomorphology. The mapping and monitoring of ice-free areas is important as they are highly sensitive to climate change. The objective of this study was to characterize and map surface landforms in ice-free areas using traditional mapping methods as well as advanced remote sensing techniques. Geomorphological and topographical maps were initially obtained through field measurements and observations, and complemented with existing aerial photography at scales between 1:2000 and 1:25000. Thereafter, satellite-borne data became available and were included in the methodology to further determine the distribution of the landforms. In the Antarctic environment, Synthetic Aperture Radar (SAR) provides the most reliable images as data can be obtained in any weather conditions as well as during the day and night. Fully polarimetric SAR RADARSAT-2 were used to determine seven different terrain classes representing surface landforms in ice-free areas around Maxwell Bay (King George Island). The SAR remote sensing techniques were successfully applied to identify different periglacial, fluvial, glacial, coastal, as well as lithological landforms. Field data from Fildes Peninsula were used to train a supervised classifier to map further areas around Maxwell Bay. In this case, the ice-free areas around Maxwell Bay clearly show the dominance of periglacial landforms and processes. Therefore, these techniques can be used to compare past and future results and to monitor areas affected by changing environmental factors and increasing human activities.

scholarly journals Population decline of the cape petrel (Daption capense) on King George Island, South Shetland Islands, Antarctica

Polar Biology ◽  
2021 ◽  
Author(s):  
Christina Braun ◽  
Jan Esefeld ◽  
Larisa Savelieva ◽  
Hans-Ulrich Peter
Keyword(s):  
Environmental Changes ◽  
Environmental Variability ◽  
Anthropogenic Impacts ◽  
Population Decline ◽  
Monitoring Program ◽  
South Shetland Islands ◽  
Fildes Peninsula ◽  
Breeding Sites ◽  
Shetland Islands

AbstractThe Antarctic and the surrounding Southern Ocean are currently subject to rapid environmental changes and increasing anthropogenic impacts. Seabird populations often reflect those changes and so act as indicators of environmental variability. Their population trends may provide information on a variety of environmental parameters on the scale of years or decades. We therefore provide long-term data on the cape petrel (Daption capense) population from a long-term monitoring program on Fildes Peninsula, South Shetland Islands, Maritime Antarctic, an area of considerable human activity. Our data, covering a period of 36 years, indicate some variability, but no clear trend in the number of breeding pairs between the breeding seasons 1985 and 2006. However, beginning in the 2008 season, the population decreased significantly and reached a minimum in the 2020 season. The mean annual decrease between 2008 and 2020 was 10.6%. We discuss possible causes of this strong negative population trend. Anthropogenic disturbance only affects a few breeding sites in the area and is therefore unable, on its own, to explain the consistent population decline at all the breeding sites studied. We think it more likely that reduced food availability was the main cause of the drastic decline in the cape petrel population.

Eocene fossil feather from King George Island, South Shetland Islands, Antarctica

2013 ◽  
Vol 26 (4) ◽  
pp. 384-388 ◽  
Author(s):  
Héctor G. Mansilla ◽  
Wolfgang Stinnesbeck ◽  
Natalia Varela ◽  
Marcelo Leppe
Keyword(s):  
Middle Eocene ◽  
Trace Fossils ◽  
South Shetland Islands ◽  
King George Island ◽  
Fildes Peninsula ◽  
Shetland Islands

AbstractThe first fossil avian feather from Antarctica is reported here, from the early to middle Eocene Fossil Hill Formation at Fildes Peninsula, King George Island, Antarctica. Characteristics such as its form, asymmetry of vanes, closed-pennaceous vanes with barbules and a deep ventral groove indicate that the feather was used for flight. The site from which the feather was collected is known to yield a variety of well-preserved trace fossils, palaeobotanical and palaeoenvironmental remains, suggesting a shorebird ecotype for the owner of this feather, certainly belonging to a Neornithes. The continental position, preservation as an external mould and type of feather makes this specimen a novel and an exceedingly rare record.

scholarly journals AN IGNEOUS EVENT AT THE FILDES PENINSULA (KING GEORGE ISLAND) AND AROUND FORT POINT (GREENWICH ISLAND), SOUTH SHETLAND ISLANDS, ANTARCTICA

2003 ◽  
Vol 33 (4) ◽  
pp. 337-346
Author(s):  
DELIA DEL PILAR MONTECINOS DE ALMEIDA ◽  
ADRIANE MACHADO ◽  
MARCO ANTÔNIO FONTOURA HANSEN ◽  
FARID CHEMALE JR. ◽  
HENRIQUE CARLOS FENSTERSEIFER ◽  
...  
Keyword(s):  
South Shetland Islands ◽  
King George Island ◽  
Fildes Peninsula ◽  
Shetland Islands

Bridgeman Island, Antarctica, ‘burning mount’ or old eroded volcano?

Polar Record ◽  
2021 ◽  
Vol 57 ◽  
Author(s):  
Karen Louise Williams
Keyword(s):  
Nineteenth Century ◽  
Volcanic Activity ◽  
South Shetland Islands ◽  
Deception Island ◽  
The South ◽  
Shetland Islands ◽  
Short Period ◽  
South Shetlands ◽  
Volcanic Islands

Abstract Deception, Bridgeman and Penguin are the three most recently active volcanic islands in the South Shetland Islands. Since the discovery of the archipelago in 1819, Deception Island has erupted on frequent occasions, most recently in August 1970. A number of nineteenth-century observers reported fumarolic or volcanic activity from Bridgeman Island. No eyewitness accounts of activity from Penguin Island have been found. A chronological list detailing the historic reports from Bridgeman Island was compiled to compare and establish their veracity. This process revealed a consistency of observation from independent observers. An effort has been made to consider if any of these reports of activity may have belonged instead to Penguin Island volcano, 60 km (32 NM) away. A review of the timing of discovery and availability of the first charts of the South Shetlands was also examined to narrow the period when mariners might have mistaken one island for another. Only the three earliest observations of activity from an unnamed volcano, during the short period when no maps were available, may be questioned. A useful chart of the region was published in 1822, and all subsequent observations of activity were from Bridgeman, not Penguin Island.

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