Tectonics of the West Antarctic rift system: new light on the history and dynamics of distributed intracontinental extension

Siddoway, C. S.

doi:10.3133/ofr20071047kp09

Cited by 64 publications

(119 citation statements)

References 138 publications

(261 reference statements)

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“…Figures modified from Korhonen et al (2010b). at pressures of 0.75 -1.15 GPa and temperatures of c. 870 8C, and a Cretaceous event at pressures of 0.60-0.75 GPa and temperatures of 830 -870 8C (Korhonen et al 2010a(Korhonen et al , 2012. Elevated temperatures and crustal melting in the Palaeozoic are attributed to thickening of the continental margin during calc-alkaline arc magmatism represented by the Ford Granodiorite suite (Pankhurst et al 1998;Siddoway & Fanning 2009), and in the Mesozoic are attributed to moderate thickening followed by lithosphere thinning during intracontinental extension across the West Antarctic rift system (Siddoway 2008). Coeval with Cretaceous rifting, mafic dykes of c. 113 Ma to c. 98 Ma age were intruded throughout the Fosdick complex (Saito et al 2013).…”

Section: Geological Settingmentioning

confidence: 97%

“…In Marie Byrd Land, both the Swanson Formation and the Ford Granodiorite suite are intruded by the Lower Cretaceous Byrd Coast Granite suite (Fig. 1c;Adams 1987;Siddoway 2008), which is the main plutonic phase emplaced during the intracontinental extension that preceded break-up of Marie Byrd Land (Siddoway et al 2004b(Siddoway et al , 2005McFadden et al 2010a) and Zealandia (Mortimer 2004).…”

Section: Geological Settingmentioning

confidence: 98%

“…The inferred location of the boundary between the Ross and Amundsen provinces is from Mukasa & Dalziel (2000). (c) Geological map of the Ford Ranges (Siddoway 2008) with the locations for sample sites outside the Fosdick migmatite-granite complex. (d) Geological map of the Fosdick migmatite-granite complex (McFadden et al 2010b).…”

Section: Geological Settingmentioning

confidence: 99%

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Anatectic reworking and differentiation of continental crust along the active margin of Gondwana: a zircon Hf–O perspective from West Antarctica

Yakymchuk

Siddoway

McFadden

et al. 2013

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The Fosdick migmatite-granite complex of West Antarctica preserves evidence of two crustal differentiation events along a segment of the former active margin of Gondwana, one in the Devonian-Carboniferous and another in the Cretaceous. The Hf-O isotope composition of zircons from Devonian -Carboniferous granites is explained by mixing of material from two crustal sources represented by the high-grade metamorphosed equivalents of a Lower Palaeozoic turbidite sequence and a Devonian calc-alkaline plutonic suite, consistent with an interpretation that the Devonian-Carboniferous granites record crustal reworking without input from a more juvenile source. The Hf-O isotope composition of zircons from Cretaceous granites reflects those same two sources, together with a contribution from a more juvenile source that is most evident in the detachment-hosted, youngest granites. The relatively non-radiogenic 1Hf isotope characteristics of zircons from the Fosdick complex granites are similar those from the Permo-Triassic granites from the Antarctic Peninsula. However, the Fosdick complex granites contrast with coeval granites in other localities along and across the former active margin of Gondwana, including the Tasmanides of Australia and the Western Province of New Zealand, where the wider range of more radiogenic 1Hf values of zircon suggests that crustal growth through the addition of juvenile material plays a larger role in granite genesis. These new results highlight prominent arc-parallel and arc-normal variations in the mechanisms and timing of crustal reworking v. crustal growth along the former active margin of Gondwana.

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Section: Geological Settingmentioning

confidence: 97%

Section: Geological Settingmentioning

confidence: 98%

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Anatectic reworking and differentiation of continental crust along the active margin of Gondwana: a zircon Hf–O perspective from West Antarctica

Yakymchuk

Siddoway

McFadden

et al. 2013

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“…Tectonic models for the rift system typically invoke phases of extension in the Cretaceous and Cenozoic (Cooper et al, 1987;Tessensohn and Wörner, 1991;Davey and Brancolini, 1995;Salvini et al, 1997;Fitzgerald, 2002;Karner et al, 2005;Huerta and Harry, 2007;Bialas et al, 2007;Siddoway, 2008;Wilson and Luyendyk, 2009). Seismic studies indicate at least two distinct periods of Cenozoic rifting (Paleogene and Neogene) within the western Ross Sea.…”

Section: Geologic Backgroundmentioning

confidence: 98%

Kinematics of the Neogene Terror Rift: Constraints from calcite twinning strains in the ANDRILL McMurdo Ice Shelf (AND-1B) core, Victoria Land Basin, Antarctica

et al. 2014

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We report new strain analyses of mechanically twinned calcite in veins hosted by Neogene (13.6-4.3 Ma) sedimentary and volcanic rocks recovered from the Terror Rift system in the southern Ross Sea, Antarctica, by the ANDRILL (ANtarctic geological DRILLing) McMurdo Ice Shelf (MIS) Project. Strain analyses of the ANDRILL MIS AND-1Bdrill core samples yield prolate and oblate ellipsoids with principal shortening and extension strains ranging from -7% to 9%, respectively. The majority of samples show ≤25% negative expected values, indicating homogeneous coaxial strain characterized predominantly by subvertical shortening. We attribute the subvertical shortening strains to mechanical twinning at relatively shallow depths in an Andersonian normal faulting stress regime induced by sedimentary and ice sheet loading of the stratigraphic sequence and characterized by low stress magnitudes. Oriented samples yield a northwest-southeast average extension direction that is subparallel to other indicators of Neogene extension. This northwest-southeast extension is consistent with strain predicted by Neogene orthogonal rifting in a north-northeast-trending rift segment, as well as models of right-lateral transtensional rifting. The overall paucity of a noncoaxial layer-parallel shortening signal in the AND-1B twin populations favors orthogonal extension in the Neogene Terror Rift system, but could also be due to spatial partitioning of strain in a transtensional rift regime.

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“…Rifting was also widespread in West Antarctica at c. 100 Ma, resulting in extension, A-type magmatism and metamorphism in Marie Byrd Land. This was linked to development of the West Antarctic Rift System (Mukasa & Dalziel 2000;Siddoway 2008), and the separation of New Zealand and other blocks away from West Antarctica (Mortimer 2004), leaving Antarctica in more or less its presentday configuration.…”

Section: The Gondwana Marginmentioning

confidence: 99%

Antarctica and supercontinent evolution: historical perspectives, recent advances and unresolved issues

Harley

Fitzsimons

Zhao

2013

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The Antarctic rock record spans some 3.5 billion years of history, and has made important contributions to our understanding of how Earth's continents assemble and disperse through time. Correlations between Antarctica and other southern continents were critical to the concept of Gondwana, the Palaeozoic supercontinent used to support early arguments for continental drift, while evidence for Proterozoic connections between Antarctica and North America led to the 'SWEAT' configuration (linking SW USA to East Antarctica) for an early Neoproterozoic supercontinent known as Rodinia. Antarctica also contains relicts of an older Palaeo-to Mesoproterozoic supercontinent known as Nuna, along with several Archaean fragments that belonged to one or more 'supercratons' in Neoarchaean times. It thus seems likely that Antarctica contains remnants of most, if not all, of Earth's supercontinents, and Antarctic research continues to provide insights into their palaeogeography and geological evolution. One area of research is the latest Neoproterozoic-Mesozoic active margin of Gondwana, preserved in Antarctica as the Ross Orogen and a number of outboard terranes that now form West Antarctica. Major episodes of magmatism, deformation and metamorphism along this palaeo-Pacific margin at 590 -500 and 300-230 Ma can be linked to reduced convergence along the internal collisional orogens that formed Gondwana and Pangaea, respectively; indicating that accretionary systems are sensitive to changes in the global plate tectonic budget. Other research has focused on Grenville-age (c. 1.0 Ga) and PanAfrican (c. 0.5 Ga) metamorphism in the East Antarctic Craton. These global-scale events record the amalgamation of Rodinia and Gondwana, respectively. Three coastal segments of Grenville-age metamorphism in the Indian Ocean sector of Antarctica are each linked to the c. 1.0 Ga collision between older cratons but are separated by two regions of pervasive Pan-African metamorphism ascribed to Neoproterozoic ocean closure. The tectonic setting of these events is poorly constrained given the sparse exposure, deep erosion level and likelihood that younger metamorphic events have reactivated older structures. The projection of these orogens under the ice is also controversial, but it is likely that at least one of the Pan-African orogens links up with the Shackleton Range on the palaeo-Pacific margin of the craton. Sedimentary detritus and glacial erratics at the edge of the ice sheet provide evidence for the c.

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Tectonics of the West Antarctic rift system: new light on the history and dynamics of distributed intracontinental extension

Cited by 64 publications

References 138 publications

Anatectic reworking and differentiation of continental crust along the active margin of Gondwana: a zircon Hf–O perspective from West Antarctica

Anatectic reworking and differentiation of continental crust along the active margin of Gondwana: a zircon Hf–O perspective from West Antarctica

Kinematics of the Neogene Terror Rift: Constraints from calcite twinning strains in the ANDRILL McMurdo Ice Shelf (AND-1B) core, Victoria Land Basin, Antarctica

Antarctica and supercontinent evolution: historical perspectives, recent advances and unresolved issues

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