European geological initiative for the Shackleton Range

1990 ◽  
Vol 2 (3) ◽  
pp. 265-266
Author(s):  
F. Tessensohn ◽  
M.R.A. Thomson
Keyword(s):  
Continental Margin ◽  
West Antarctica ◽  
Structural Orientation ◽  
The Pacific ◽  
Dronning Maud Land ◽  
Pacific Margin ◽  
East And West ◽  
The Antarctic ◽  
The Relationship ◽  
Geological Position

The Shackleton Range occupies a key geological position in Antarctica (Fig. 1). Its location, at the edge of the continental craton between the mobile belts of the Transantarctic Mountains (TAM) and the stable platform of Dronning Maud Land (Neuschwabenland), and its geological constitution offer possibilities for: understanding the nature of the ‘Pacific’ margin of the Antarctic craton during the Palaeozoic, distinguishing between subduction- and collision-related tectonics at an ancient continental margin, and contributing to the debate on the relationship between East and West Antarctica. The structural orientation of the range, at right angles to the trend of the TAM, has puzzled geologists ever since its discovery.

First Finding of the Orbicular Gabbroids in the Ukrainian Antarctic Station Area (Wilhelm Archipelago, West Antarctica)

2021 ◽  
Vol 43 (2) ◽  
pp. 40-48
Author(s):  
O.V. MYTROKHYN ◽  
V.G. BAKHMUTOV
Keyword(s):  
Mineral Composition ◽  
Small Area ◽  
Texture Features ◽  
West Antarctica ◽  
First Finding ◽  
Petrographic Feature ◽  
The Antarctic ◽  
Petrographic Description ◽  
Porphyritic Texture ◽  
Geological Position

A new occurrence of igneous rocks with an orbicular structure was discovered by the authors in West Antarctica. The place of finding is Hovgaard Island in the Wilhelm Archipelago located near the Graham Coast of the Antarctic Peninsula. Until now, not a single manifestation of these rare rocks was known in this region. Usually orbicular rocks are formed under the condition of local "coincidence" of many geological and petrogenetic factors. The study of the geological position, texture features and mineral composition of the orbicular rocks on Hovgaard Island was carried out in order to create their primary petrographic description. It was found that orbiculites are exposed in a small area, about 200 m2, in the field of amphibolized gabbroids and their intrusive breccias. The occurrence and textures of the orbiculites indicate that their crystallization occurred at the hypabyssal depth. Probably, this occurrence is a marginal facies of a small gabbroid intrusion, some parts of which are exposed on the adjacent coastal areas of Hovgaard Island. The studies performed have shown that the orbiculites of Hovgaard Island belong to the rarest petrographic representatives of these rocks namely orbicular gabbroids. In their petrographic feature, they differ markedly from the famous French napoleonites (corsites) exposed on the Corsica Island. The mineral composition of the orbicules is represented by calcium plagioclase (An88-97), hornblende (#Mg = 0.77-0.81), clinopyroxene (Wo48-50En43-47Fs5-8), spinel (Sp62-72Hrc14-20Mt12-17), actinolite, phlogopite, chlorite, magnetite and apatite. The interorbicular matrix has a gabbroid composition and a porphyritic texture. It differs from orbicules in somewhat less calcium plagioclase and less magnesian hornblende, as well as in the absence of spinel. In view of the rarity of orbicular gabbroids and the specificity of the described manifestation, it is proposed that the orbicular gabbro on Hovgaard Island be considered as a new petrographic variety of the gabbroid family. The name "hovgaardite" is recommended for the name of this variety of orbicular gabbro.

Chapter 3.1b Antarctic Peninsula and South Shetland Islands: petrology

2021 ◽  
pp. M55-2018-68 ◽  
Author(s):  
Philip T. Leat ◽  
Teal R. Riley
Keyword(s):  
Antarctic Peninsula ◽  
Continental Margin ◽  
Volcanic Rocks ◽  
Oceanic Lithosphere ◽  
Contact Metamorphism ◽  
South Shetland Islands ◽  
Calc Alkaline ◽  
The Pacific ◽  
High K ◽  
The Antarctic

AbstractThe Antarctic Peninsula contains a record of continental-margin volcanism extending from Jurassic to Recent times. Subduction of the Pacific oceanic lithosphere beneath the continental margin developed after Late Jurassic volcanism in Alexander Island that was related to extension of the continental margin. Mesozoic ocean-floor basalts emplaced within the Alexander Island accretionary complex have compositions derived from Pacific mantle. The Antarctic Peninsula volcanic arc was active from about Early Cretaceous times until the Early Miocene. It was affected by hydrothermal alteration, and by regional and contact metamorphism generally of zeolite to prehnite–pumpellyite facies. Distinct geochemical groups recognized within the volcanic rocks suggest varied magma generation processes related to changes in subduction dynamics. The four groups are: calc-alkaline, high-Mg andesitic, adakitic and high-Zr, the last two being described in this arc for the first time. The dominant calc-alkaline group ranges from primitive mafic magmas to rhyolite, and from low- to high-K in composition, and was generated from a mantle wedge with variable depletion. The high-Mg and adakitic rocks indicate periods of melting of the subducting slab and variable equilibration of the melts with mantle. The high-Zr group is interpreted as peralkaline and may have been related to extension of the arc.

scholarly journals Gas Hydrates Accumulations on the South Shetland Continental Margin: New Detection Possibilities

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
V. D. Solovyov ◽  
V. G. Bakhmutov ◽  
I. N. Korchagin ◽  
S. P. Levashov ◽  
N. A. Yakymchuk ◽  
...  
Keyword(s):  
Data Processing ◽  
Continental Margin ◽  
Satellite Data ◽  
Gas Hydrates ◽  
Oil And Gas ◽  
West Antarctica ◽  
The South ◽  
Deposit Type ◽  
Pulsed Electromagnetic ◽  
The Antarctic

The results of investigations in 2006–2010 for hydrocarbon and gas hydrates on the Antarctic Peninsula continental margin are given. In 2004 and 2006, the marine geoelectric researches by methods of forming a short-pulsed electromagnetic field (FSPEF) and vertical electric-resonance sounding (VERS) had been conducted in this region. The “deposit” type anomaly was mapped by FSPEF survey, and anomalous polarized layers of “hydrocarbon deposit” type were chosen by VERS sounding within this anomaly on Antarctic margin in the region of UAS “Academician Vernadsky.” Anomalous zones of “gas hydrate deposit” type were detected on the South Shetland margin due to the special technology of satellite data processing and interpretation using. These results confirm the high gas hydrates potential of the West Antarctica region. Some practical results of the experimental approbation of these original technologies for the “direct” prospecting and exploration of hydrocarbon (HC) and gas hydrates accumulations in different oil-and-gas bearing basins of Russia and Gulf of Mexico are proposed. The integration of satellite data processing and materials of FSPEF-VERS methods enable improving their efficiency for different geological and geophysical problems solving.

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.

Chapter 2.2a Palmer Land and Graham Land volcanic groups (Antarctic Peninsula): volcanology

2021 ◽  
pp. M55-2018-36 ◽  
Author(s):  
Teal R. Riley ◽  
Philip T. Leat
Keyword(s):  
Antarctic Peninsula ◽  
Volcanic Rocks ◽  
Flood Basalt ◽  
Large Igneous Province ◽  
West Antarctica ◽  
Silicic Volcanic ◽  
Pacific Margin ◽  
Southward Extension ◽  
Continental Magmatism ◽  
The Antarctic

AbstractThe break-up of Gondwana during the Early–Middle Jurassic was associated with flood basalt volcanism in southern Africa and Antarctica (Karoo–Ferrar provinces), and formed one of the most extensive episodes of continental magmatism of the Phanerozoic. Contemporaneous felsic magmatism along the proto-Pacific margin of Gondwana has been referred to as a silicic large igneous province, and is exposed extensively in Patagonian South America, the Antarctic Peninsula and elsewhere in West Antarctica. Jurassic-age silicic volcanism in Patagonia is defined as the Chon Aike province and forms one of the most voluminous silicic provinces globally. The Chon Aike province is predominantly pyroclastic in origin, and is characterized by crystal tuffs and ignimbrite units of rhyolite composition. Silicic volcanic rocks of the once contiguous Antarctic Peninsula form a southward extension of the Chon Aike province and are also dominated by silicic ignimbrite units, with a total thickness exceeding 1 km. The ignimbrites include high-grade rheomorphic ignimbrites, as well as 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.

scholarly journals New Geophysical Data About the Pacific Margin (West Antarctica) Magnetic Anomaly Sources and Origin

2019 ◽  
pp. 20-31
Author(s):  
V. D. Soloviev ◽  
◽  
V. G. Bakhmutov ◽  
I. N. Korchagin ◽  
T. P. Yegorova ◽  
...  
Keyword(s):  
Magnetic Anomaly ◽  
Geophysical Data ◽  
West Antarctica ◽  
The Pacific ◽  
Pacific Margin

Precise dating of centennial-millennial scale climate variations in sediment archives from the Antarctic continental margin off Dronning Maud Land by 14C plateau tuning

2020 ◽  
Author(s):  
Ralf Tiedemann ◽  
Juliane Müller ◽  
Lester Lembke-Jene ◽  
Gesine Mollenhauer
Keyword(s):  
Ocean Circulation ◽  
Continental Margin ◽  
Ice Core ◽  
Climate And Environmental Change ◽  
Rapid Changes ◽  
Climate Interactions ◽  
Dronning Maud Land ◽  
Paleoclimate Records ◽  
Proxy Reconstructions ◽  
The Antarctic

<p>Rapid changes in ocean circulation and polar temperature variability have been observed in glacial and deglacial paleoclimate records from marine and ice core archives. However, an obstacle to progress in understanding the ice-ocean-bedrock-climate interactions on centennial-millennial timescales is due to the paucity of sediment records with precise chronologies. The sediment archive along the continental margin of Dronning Maud Land provides an excellent opportunity for high resolution <sup>14</sup>C dating as it contains sufficient amounts of planktonic foraminifers. We dated a 7 m long sediment sequence from core PS111/13 by means of <sup>14</sup>C plateau tuning (Sarnthein et al., 2015) to produce a solid chronological framework for multi-proxy reconstructions of climate and environmental change from 7000 to 30,000 years that can be linked to ice core chronologies.</p><p>Sarnthein et al., Radiocarbon, 2015, <span>57 (1), 129–151.</span></p>

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