Paleozoic tectonism on the East Gondwana margin: Evidence from SHRIMP U–Pb zircon geochronology of a migmatite–granite complex in West Antarctica

2009 ◽  
Vol 477 (3-4) ◽  
pp. 262-277 ◽  
Author(s):  
Christine S. Siddoway ◽  
C. Mark Fanning
Keyword(s):  
Zircon Geochronology ◽  
West Antarctica ◽  
Gondwana Margin ◽  
Granite Complex

Ultramafic mantle xenoliths in the Late Cenozoic Volcanic rocks of the Antarctic Peninsula and Jones Mountains, West Antarctica

2021 ◽  
pp. M56-2019-44
Author(s):  
Philip T. Leat ◽  
Aidan J. Ross ◽  
Sally A. Gibson
Keyword(s):  
Antarctic Peninsula ◽  
Upper Mantle ◽  
Lithospheric Mantle ◽  
Volcanic Rocks ◽  
Oceanic Lithosphere ◽  
Incompatible Trace Element ◽  
Mantle Xenoliths ◽  
South Shetland Islands ◽  
West Antarctica ◽  
Gondwana Margin

AbstractAbundant mantle-derived ultramafic xenoliths occur in Cenozoic (7.7-1.5 Ma) mafic alkaline volcanic rocks along the former active margin of West Antarctica, that extends from the northern Antarctic Peninsula to Jones Mountains. The xenoliths are restricted to post-subduction volcanic rocks that were emplaced in fore-arc or back-arc positions relative to the Mesozoic-Cenozoic Antarctic Peninsula volcanic arc. The xenoliths are spinel-bearing, include harzburgites, lherzolites, wehrlites and pyroxenites, and provide the only direct evidence of the composition of the lithospheric mantle underlying most of the margin. The harzburgites may be residues of melt extraction from the upper mantle (in a mid-ocean ridge type setting), that accreted to form oceanic lithosphere, which was then subsequently tectonically emplaced along the active Gondwana margin. An exposed highly-depleted dunite-serpentinite upper mantle complex on Gibbs Island, South Shetland Islands, supports this interpretation. In contrast, pyroxenites, wehrlites and lherzolites reflect percolation of mafic alkaline melts through the lithospheric mantle. Volatile and incompatible trace element compositions imply that these interacting melts were related to the post-subduction magmatism which hosts the xenoliths. The scattered distribution of such magmatism and the history of accretion suggest that the dominant composition of sub-Antarctic Peninsula lithospheric mantle is likely to be harzburgitic.

Separating metamorphic events in the Fosdick migmatite-granite complex, West Antarctica

2011 ◽  
Vol 30 (2) ◽  
pp. 165-192 ◽  
Author(s):  
F. J. KORHONEN ◽  
M. BROWN ◽  
M. GROVE ◽  
C. S. SIDDOWAY ◽  
E. F. BAXTER ◽  
...  
Keyword(s):  
West Antarctica ◽  
Granite Complex

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.

scholarly journals Granitoids and dykes of the Pine Island Bay region, West Antarctica

2012 ◽  
Vol 24 (5) ◽  
pp. 473-484 ◽  
Author(s):  
Andrea Kipf ◽  
Nicholas Mortimer ◽  
Reinhard Werner ◽  
Karsten Gohl ◽  
Paul Van Den Bogaard ◽  
...  
Keyword(s):  
Trace Element ◽  
Granitic Rocks ◽  
Geochemical Data ◽  
West Antarctica ◽  
Laser Method ◽  
Bay Area ◽  
Gondwana Margin ◽  
Plutonic Rocks ◽  
Age Range

AbstractWe present geochronological and geochemical data for eight plutonic rocks from five locations in the Pine Island Bay area of West Antarctica, collected during RV Polarstern expedition ANT-XXIII/4. Ar-Ar laser method dating yielded closure temperatures ages of c. 147–98 Ma for dioritic and granitic plutonic rocks and an age range of c. 97–95 Ma for granitoid and trachyandesitic dykes. Major and trace element compositions indicate that all rocks have an I-type subduction-related chemistry. There are no A-type granitic rocks in our dataset, and none are yet reported from the Pine Island Bay area. Our results confirm earlier models of post 100 Ma subduction on this part of the Gondwana margin.

scholarly journals From Source to Sink: Petrogenesis of Cretaceous Anatectic Granites from the Fosdick Migmatite–Granite Complex, West Antarctica

2016 ◽  
Vol 57 (7) ◽  
pp. 1241-1278 ◽  
Author(s):  
C. R. Brown ◽  
C. Yakymchuk ◽  
M. Brown ◽  
C. M. Fanning ◽  
F. J. Korhonen ◽  
...  
Keyword(s):  
West Antarctica ◽  
Source To Sink ◽  
Granite Complex

Chapter 1.3 Antarctic volcanism: petrology and tectonomagmatic overview

2021 ◽  
pp. M55-2020-10 ◽  
Author(s):  
Kurt Samuel Panter
Keyword(s):  
West Antarctica ◽  
Origin And Evolution ◽  
Tectonic History ◽  
Intraplate Magmatism ◽  
Mantle Sources ◽  
Gondwana Margin ◽  
History Of ◽  
Competing Models ◽  
The Antarctic ◽  
Metasomatized Mantle

AbstractPetrological investigations over the past 30 years have significantly advanced our knowledge of the origin and evolution of magmas emplaced within and erupted on top of the Antarctic Plate. Over the last 200 myr Antarctica has experienced: (1) several episodes of rifting, leading to the fragmentation of Gondwana and the formation by c. 83 Ma of the current Antarctica Plate; (2) long-lived subduction that shut down progressively eastwards along the Gondwana margin in the Late Cretaceous and is still active at the northernmost tip of the Antarctic Peninsula; and (3) broad extension across West Antarctica that produced one of the Earth's major continental rift systems. The dynamic tectonic history of Antarctica since the Triassic has led to a diversity of volcano types and igneous rock compositions with correspondingly diverse origins. Many intriguing questions remain about the petrology of mantle sources and the mechanisms for melting during each tectonomagmatic phase. For intraplate magmatism, the upwelling of deep mantle plumes is often evoked. Alternatively, subduction-related metasomatized mantle sources and melting by more passive means (e.g. edge-driven flow, translithospheric faulting, slab windows) are proposed. A brief review of these often competing models is provided in this chapter along with recommendations for ongoing petrological research in Antarctica.

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