scholarly journals Características Tectónicas de Áreas de Aporte para Arenas de Playas de Tierra del Fuego y Península Antártica, Argentina

2000 ◽  
Vol 27 (1) ◽  
pp. 69
Author(s):  
EDGARDO MARTÍN GELOS ◽  
JORGE OSVALDO SPAGNUOLO ◽  
FEDERICO IGNACIO ISLA
Keyword(s):  
Antarctic Peninsula ◽  
Tectonic Setting ◽  
Active Continental Margin ◽  
Mineralogical Composition ◽  
Tierra Del Fuego ◽  
Heavy Minerals ◽  
Island Arcs ◽  
Sediment Sources ◽  
Pacific Margin ◽  
The Antarctic

Sand mineralogical analysis from 22 beaches were performed within the southernmost area of Argentina (Isla Grande de Tierra del Fuego), the Antarctic Peninsula and the Scotia Arc (South Orkney, South Shetland and James Ross islands included). Composition triangles of light and heavy minerals were considered in order to relate them to depocenters, sediment sources and tectonic setting. 71% of the sediments would have been transported from magmatic arcs, 24% from elevated crystalline basements and only 5% from recycled orogene. In regard to the heavy mineral distribution, 70% were assigned to a suite from an active continental margin and the remaining 30% would correspond to areas outside the continental margins (volcanic arcs). In a general way, sediment sources were related to active margins or volcanic island arcs. As an anomalous fact, it is stressed that the coasts of Tierra del Fuego and the western sector of the Antarctic Peninsula and adjacent islands, contain sediments from a Pacific margin but lying on a passive Atlantic margin. Finally, it should be adviced about the convenience to know the source areas when ice is the transport agent, as it avoids a selective ability and it does not modify the original mineralogical composition.

Petrography and geochemistry of the Carboniferous–Triassic Trinity Peninsula Group, West Antarctica: implications for provenance and tectonic setting

2014 ◽  
Vol 152 (4) ◽  
pp. 575-588 ◽  
Author(s):  
PAULA CASTILLO ◽  
JUAN PABLO LACASSIE ◽  
CARITA AUGUSTSSON ◽  
FRANCISCO HERVÉ
Keyword(s):  
Antarctic Peninsula ◽  
Tectonic Setting ◽  
Active Continental Margin ◽  
Source Area ◽  
Major And Trace Elements ◽  
Cold Climate ◽  
West Antarctica ◽  
Continental Arc ◽  
Uplift And Erosion ◽  
The Antarctic

AbstractThe Carboniferous-Triassic Trinity Peninsula Group is a metasedimentary sequence that crops out widely in the northern Antarctic Peninsula. These are some of the most extensive outcrops in the area and hold the key to evaluating the connections of the Antarctic Peninsula in Gondwana; however, they are still poorly understood. Here we present our provenance study of the Trinity Peninsula Group using petrographic and geochemical approaches in combination with cathodoluminescence of detrital quartz in order to constrain its source characteristics and tectonic setting. Using differences in modal composition and quartz cathodoluminescence characteristics, we define three petrofacies derived from the progressive uplift and erosion of a volcano-plutonic continental arc, which exposed the plutonic-metamorphic roots. As indicated by major and trace elements, the source is felsic with a composition ranging from tonalitic to granodioritic. The relatively unweathered condition of the source area points to a dry and cold climate at the time of deposition, but this does not necessarily mean that it was glaciated. Deposition of the sediments occurred within an active continental margin, relatively close to the source area, probably along the south Patagonia–Antarctic Peninsula sector of Gondwana. Strong chronological, petrological and chemical similarities with the sediments of the Duque the York Complex in Patagonia suggest that they were derived from the same source.

Chapter 4.1b Antarctic Peninsula: petrology

2021 ◽  
pp. M55-2018-40
Author(s):  
Malcolm J. Hole
Keyword(s):  
Antarctic Peninsula ◽  
Tectonic Setting ◽  
Volcanic Rocks ◽  
Passive Margin ◽  
Ridge Crest ◽  
Ridge Subduction ◽  
Simple Geometry ◽  
Key Issues ◽  
The Antarctic ◽  
Slab Window

AbstractScattered occurrences of Miocene–Recent volcanic rocks of the alkaline intraplate association represent one of the last expressions of magmatism along the Antarctic Peninsula. The volcanic rocks were erupted after the cessation of subduction which stopped following a series of northward-younging ridge crest–trench collisions. Volcanism has been linked to the development of a growing slab window beneath the extinct convergent margin. Geochemically, lavas range from olivine tholeiite through to basanite and tephrite. Previous studies have emphasized the slab-window tectonic setting as key to allowing melting of peridotite in the asthenospheric void caused by the passage of the slab beneath the locus of volcanism. This hypothesis is revisited in the light of more recent petrological research, and an origin from melting of subducted slab-hosted pyroxenite is considered here to be a more viable alternative for their petrogenesis. Because of the simple geometry of ridge subduction, and the well-established chronology of ridge crest–trench collisions, the Antarctic Peninsula remains a key region for understanding the transition from active to passive margin resulting from cessation of subduction. However, there are still some key issues relating to their tectonomagmatic association, and, principally, the poor geochronological control on the volcanic rocks requires urgent attention.

scholarly journals Permo-Carboniferous conglomerates in the Trinity Peninsula Group at View Point, Antarctic Peninsula: sedimentology, geochronology and isotope evidence for provenance and tectonic setting in Gondwana

2011 ◽  
Vol 149 (4) ◽  
pp. 626-644 ◽  
Author(s):  
JOHN D. BRADSHAW ◽  
ALAN P. M. VAUGHAN ◽  
IAN L. MILLAR ◽  
MICHAEL J. FLOWERDEW ◽  
RUDOLPH A. J. TROUW ◽  
...  
Keyword(s):  
Antarctic Peninsula ◽  
Detrital Zircon ◽  
Tectonic Setting ◽  
Detrital Zircons ◽  
View Point ◽  
Transport Distance ◽  
Clastic Sedimentary ◽  
Detrital Zircon Ages ◽  
The Antarctic ◽  
The Trinity

AbstractField observations from the Trinity Peninsula Group at View Point on the Antarctic Peninsula indicate that thick, southward-younging and overturned clastic sedimentary rocks, comprising unusually coarse conglomeratic lenses within a succession of fine-grained sandstone–mudstone couplets, are the deposits of debris and turbidity flows on or at the foot of a submarine slope. Three detrital zircons from the sandstone–mudstone couplets date deposition at 302 ± 3 Ma, at or shortly after the Carboniferous–Permian boundary. Conglomerates predominantly consist of quartzite and granite and contain boulders exceeding 500 mm in diameter. Zircons from granitoid clasts and a silicic volcanic clast yield U–Pb ages of 466 ± 3 Ma, 373 ± 5 Ma and 487 ± 4 Ma, respectively and have corresponding average εHft values between +0.3 and +7.6. A quartzite clast, conglomerate matrix and sandstone interbedded with the conglomerate units have broadly similar detrital zircon age distributions and Hf isotope compositions. The clast and detrital zircon ages match well with sources within Patagonia; however, the age of one granite clast and the εHf characteristics of some detrital zircons point to a lesser South Africa or Ellsworth Mountain-like contribution, and the quartzite and granite-dominated composition of the conglomerates is similar to upper Palaeozoic diamictites in the Ellsworth Mountains. Unlike detrital zircons, large conglomerate clasts limit possible transport distance, and suggest sedimentation took place on or near the edge of continental crust. Comparison with other upper Palaeozoic to Mesozoic sediments in the Antarctic Peninsula and Patagonia, including detrital zircon composition and the style of deformation, suggests deposition of the Trinity Peninsula Group in an upper plate basin on an active margin, rather than a subduction-related accretionary setting, with slow extension and rifting punctuated by short periods of compression.

scholarly journals A revised geochronology of Thurston Island, West Antarctica, and correlations along the proto-Pacific margin of Gondwana

2016 ◽  
Vol 29 (1) ◽  
pp. 47-60 ◽  
Author(s):  
T.R. Riley ◽  
M.J. Flowerdew ◽  
R.J. Pankhurst ◽  
P.T. Leat ◽  
I.L. Millar ◽  
...  
Keyword(s):  
Antarctic Peninsula ◽  
West Antarctica ◽  
Granitoid Magmatism ◽  
Andean Cordillera ◽  
Crustal Block ◽  
Form Part ◽  
Gondwana Margin ◽  
Pacific Margin ◽  
Mesozoic Magmatism ◽  
The Antarctic

AbstractThe continental margin of Gondwana preserves a record of long-lived magmatism from the Andean Cordillera to Australia. The crustal blocks of West Antarctica form part of this margin, with Palaeozoic–Mesozoic magmatism particularly well preserved in the Antarctic Peninsula and Marie Byrd Land. Magmatic events on the intervening Thurston Island crustal block are poorly defined, which has hindered accurate correlations along the margin. Six samples are dated here using U-Pb geochronology and cover the geological history on Thurston Island. The basement gneisses from Morgan Inlet have a protolith age of 349±2 Ma and correlate closely with the Devonian–Carboniferous magmatism of Marie Byrd Land and New Zealand. Triassic (240–220 Ma) magmatism is identified at two sites on Thurston Island, with Hf isotopes indicating magma extraction from Mesoproterozoic-age lower crust. Several sites on Thurston Island preserve rhyolitic tuffs that have been dated at 182 Ma and are likely to correlate with the successions in the Antarctic Peninsula, particularly given the pre-break-up position of the Thurston Island crustal block. Silicic volcanism was widespread in Patagonia and the Antarctic Peninsula at ~ 183 Ma forming the extensive Chon Aike Province. The most extensive episode of magmatism along the active margin took place during the mid-Cretaceous. This Cordillera ‘flare-up’ event of the Gondwana margin is also developed on Thurston Island with granitoid magmatism dated in the interval 110–100 Ma.

First airborne gravity wave observations at the world’s hotspot in Southern Argentina

2020 ◽  
Author(s):  
Markus Rapp ◽  
Bernd Kaifler ◽  
Andreas Dörnbrack ◽  
Sonja Gisinger ◽  
Tyler Mixa ◽  
...  
Keyword(s):  
Gravity Wave ◽  
Antarctic Peninsula ◽  
Wave Activity ◽  
Airborne Lidar ◽  
Tierra Del Fuego ◽  
Mountain Waves ◽  
The Andes ◽  
Chemistry Research ◽  
The World ◽  
The Antarctic

<p>The region around Southern Argentina and the Antarctic peninsula is known as the world’s strongest hotspot of stratospheric gravity wave activity. In this region, large tropospheric winds are perturbed by the orography of the Andes and the Antarctic peninsula resulting in the excitation of mountain waves which might propagate all the way up into the upper mesosphere when the polar night jet is intact. In addition, satellite observations also show large stratospheric wave activity in the region of the Drake passage, i.e., in between the Andes and the Antarctic peninsula, and along the corresponding latitudinal circle of 60°S. The origin of these waves is currently not entirely understood. Several hypotheses are currently being investigated, like for example the idea that the mountain waves that were originally excited over the Andes and the Antarctic peninsula propagate horizontally to 60°S and along the latitudinal circle. In order to investigate this and other hypotheses the German research aircraft HALO was deployed to Rio Grande, Tierra del Fuego, at the Southern Tip of Argentina in September and November 2019 in the frame of the SOUTHTRAC (Southern hemisphere Transport, Dynamics, and Chemistry) research mission. A total of 6 dedicated research flights with a typical length of 7000km were conducted to obtain gravity wave observations with the newly developed ALIMA (ALIMA=Airborne LIdar for Middle Atmosphere research)-instrument and the GLORIA (GLORIA=Gimballed Limb Observer for Radiance Imaging of the Atmosphere) limb sounder. While ALIMA measures temperatures and temperature perturbations in the altitude range from 20-90 km, GLORIA observations allow to characterize wave perturbations in temperatures and trace gas concentrations below flight level (<~14 km). This paper gives an overview of the mission objectives, the prevailing atmospheric conditions during the HALO deployment, and highlights some outstanding initial results of the gravity wave observations.</p>

Large volume silicic volcanism along the proto-Pacific margin of Gondwana: lithological and stratigraphical investigations from the Antarctic Peninsula

1999 ◽  
Vol 136 (1) ◽  
pp. 1-16 ◽  
Author(s):  
TEAL R. RILEY ◽  
PHILIP T. LEAT
Keyword(s):  
Antarctic Peninsula ◽  
Middle Jurassic ◽  
East Coast ◽  
Volcanic Rocks ◽  
Lower Jurassic ◽  
Fossil Flora ◽  
Metasedimentary Rocks ◽  
Close Relationship ◽  
Pacific Margin ◽  
The Antarctic

Jurassic magmatism in western Gondwana produced the most voluminous episode of continental volcanism in the Phanerozoic era. During the Early to Middle Jurassic, some 2.5–3 million km3 of dominantly basalt, and to a lesser extent rhyolite, were erupted onto a supercontinent in the early stages of break-up. The major silicic portion of the Gondwana magmatic province is exposed in Patagonian South America. The volcanic rocks of Patagonia have been collectively termed the Chon-Aike Province and constitute one of the world's most voluminous silicic provinces. The volcanic rocks are predominantly pyroclastic, dominated by ignimbrite units of rhyolite composition. Volcanic rocks crop out sporadically across much of the once contiguous Antarctic Peninsula, and are considered to form an extension of the Chon-Aike Province. A continuation of the province to include the Antarctic Peninsula would extend its strike length along the active Pacific margin by c. 2000 km.Volcanic rocks exposed along the east coast of the Antarctic Peninsula, defined here as the Mapple Formation, are also dominated by rhyolitic ignimbrite flows, with individual units up to 80 m in thickness, and a total thickness of c. 1 km. The ignimbrites vary in degree of welding, from high-grade rheomorphic ignimbrites with parataxitic textures, to unwelded, lithic-rich ignimbrites. Rhyolite lava flows, air-fall horizons, debris flow deposits and epiclastic deposits are volumetrically minor, occurring as interbedded units within the ignimbrite succession.The lithology and stratigraphy of the Jurassic volcanic rocks of the Mapple Formation are presented, and comparisons are made to the Chon-Aike Province. A consistent stratigraphy of Permo-Triassic metasedimentary rocks, unconformably overlain by terrestrial mudstone–siltstone sequences, which are in turn conformably overlain by largely silicic, subaerial volcanic rocks, is present at several localities along the Antarctic Peninsula, and at localities in the Chon-Aike Province. Precise (zircon U–Pb) Middle Jurassic ages exist for two volcanic formations from the Antarctic Peninsula, and a Middle–Lower Jurassic age has been suggested for the underlying sedimentary formations based on fossil flora analysis. The Antarctic Peninsula chronostratigraphy, coupled with lithological similarities, indicate a close relationship to those sequences of the Chon-Aike province.

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