Contrasting structural styles during polyphase granitoid intrusion, South Victoria Land, Antarctica

Jones, Sarah

doi:10.1080/00288306.1997.9514755

Cited by 8 publications

(8 citation statements)

References 22 publications

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“…It also postdates the earlier phases of supracrustal contractional deformation at 581-526 Ma in the Scott Glacier area (Encarnació n and Stump et al 2007) and the pre-531 Ma, pre-546 Ma, and pre-551 Ma deformations in South Victoria Land (Rowell et al 1993;Hall et al 1995;Encarnació n and Grunow 1996;Cook and Craw 2001;Cottle and Cooper 2006). It is also at the tail end of late Early to Late Cambrian supracrustal deformation documented elsewhere in South Victoria Land (Encarnació n and Jones 1997), the central Transantarctic Mountains (Myrow et al 2002;Goodge et al 2004;Paulsen et al 2007), the Queen Maud Mountains (Encarnació n and Encarnació n et al 1999;Grunow and Encarnació n 2000a;Paulsen et al 2004), and the Pensacola Mountains (Curtis et al 2004).…”

Section: Discussionsupporting

confidence: 59%

Late Sinistral Shearing along Gondwana’s Paleo‐Pacific Margin in the Ross Orogen, Antarctica: New Structure and Age Data from the O’Brien Peak Area

Paulsen¹,

Encarnación²,

Grunow³

et al. 2008

The Journal of Geology

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New isotopic data from O'Brien Peak, Antarctica, provide constraints on the timing of deformation within the Ross Orogen in the Queen Maud Mountains. U-Pb data, in conjunction with structural data from a mylonitic granite, indicate that sinistral, orogen-parallel ductile shearing occurred after ∼489 Ma, the granite's crystallization age, and , the 40 Ar-39 Ar cooling ages of undeformed and synkinematic white mica, respectively. before 478 ‫ע‬ 3 Ma to 473 ‫ע‬ 3 Ma These data provide evidence for the youngest sinistral shearing event within the Ross Orogen to date and indicate that left-oblique subduction possibly continued into the Early Ordovician along Gondwana's paleo-Pacific margin.

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Section: Discussionsupporting

confidence: 59%

Late Sinistral Shearing along Gondwana’s Paleo‐Pacific Margin in the Ross Orogen, Antarctica: New Structure and Age Data from the O’Brien Peak Area

Paulsen¹,

Encarnación²,

Grunow³

et al. 2008

The Journal of Geology

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“…Considerable discussion has revolved around whether the Ross orogen as a whole is a compressive (Kleinschmidt et al 1992;Stump et al 2002) or transpressive orogen (Goodge et al 1993;Jones 1997;Rocchi et al 1997;Cook & Craw 2001). Our results indicate that D 1 structures in the Shackleton Glacier area could have formed during orthogonal convergence.…”

Section: Tectonic Synthesismentioning

confidence: 56%

Structure and timing of transpressional deformation in the Shackleton Glacier area, Ross orogen, Antarctica

Paulsen

Encarnación

Grunow

2004

JGS

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Basement of the Transantarctic Mountains comprises the Ross orogenic belt, a Neoproterozoic to Ordovician mobile belt located along the palaeo-Pacific margin of Gondwana. Our structural analysis of deformation in the Liv Group, a sequence of Cambrian volcanic, volcaniclastic, clastic and carbonate rocks, and nearby plutonic rocks indicates that the Shackleton Glacier area has a polyphase deformation history that includes development of both contractional and strike-slip structures. We describe evidence for synchronous contraction and strike-slip movement, and suggest that the structural suite in this area developed, at least in part, within a sinistral transpressive kinematic regime. Deformation in the Shackleton Glacier area is inferred to be at least in part younger than 505 Ma, based on the deformation of the well-dated Taylor Formation. New 40 Ar/ 39 Ar cooling ages from metamorphosed igneous and sedimentary rocks range from c. 500 to 470 Ma and are interpreted to date orogenic cooling. Based on our structural results, and on consideration of the tectonic environment represented by the Liv Group, we propose that shortening across a subduction-related volcanic arc system caused deformation of the Liv Group and associated plutonic rocks. Oblique convergence and thus, transpression, may have ultimately been related to left-oblique plate subduction.

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“…Elsewhere, nonorthogonal shortening (e.g., Rees et al, 1987;Paulsen et al, 2004) may refl ect local strain variations due to the interactions of deforming cover and inherited basement structures. Non orthogonal deformation is also observed in the metamorphic and igneous Ross basement, which records intra-arc orogen-parallel displacements (Goodge et al, 1991(Goodge et al, , 1993aJones, 1997;Musumeci, 1999). Orogenparallel ductile fl ow in the deeper, rheologically weaker parts of the orogen directly establishes the framework of convergentmargin transpression.…”

Section: Tectonic Setting and Timing Of Active Gondwana Marginmentioning

confidence: 99%

“…The resulting thermal effects of Ross-age magmatism on basement assemblages of the Transantarctic Mountains are well known (e.g., Adams et al, 1982), suggesting that regional advective heating has greatly affected older wall-rock metamorphic assemblages. Magmatism was concomitant with tectonic deformation (Cox, 1993;Goodge et al, 1993b;Allibone et al, 1993a;Rowell et al, 1993;Hall et al, 1995;Encarnación and Grunow, 1996;Jones, 1997;Read and Cooper, 1999;Musumeci, 1999), recording intra-arc displacements through time. Some fabrics in the granitoid belt appear related mostly to emplacement process (e.g., Allibone et al, 1993a), but in other cases the strains are developed in response to regional orogenic displacement (e.g., Goodge et al, 1993b;Jones, 1997;Musumeci, 1999).…”

Section: Tectonic Setting and Timing Of Active Gondwana Marginmentioning

confidence: 99%

Metamorphism in the Ross orogen and its bearing on Gondwana margin tectonics

Goodge

2007

Convergent Margin Terranes and Associated Regions: A Tribute to W.G. Ernst

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The Ross orogen of Antarctica is one of Earth's great Phanerozoic mountain belts. It is thought from igneous geochemistry, deformation patterns, and sedimentation history to be the result of late Neoproterozoic and early Paleozoic plate-margin convergence between paleo-Pacifi c oceanic lithosphere and continental lithosphere represented by the composite East Antarctic shield. Convergence along this margin is contemporaneous with, and tectonically linked to, amalgamation of the Gondwana supercontinent following collapse of former ocean basins and collision along the East African orogen. Although there is general agreement about the large-scale tectonic framework of the Ross orogen, there is a great deal of remaining uncertainty regarding crustal province correlation, deformation kinematics, precise timing, and platemargin paleogeography. Our uncertainty stems from (1) a fragmentary record left by younger tectonic events that have modifi ed and, in some cases, removed parts of the orogen, and (2) extensive ice cover. Because the basement geology of the Ross orogen is composed largely of metamorphic rocks, however, study of the metamorphic roots of the orogen should help to constrain tectonic setting, thermal structure, tectonic displacements, cooling history, and timing. Evidence in the metamorphic domains refl ects 60-100 million years of continental-margin subduction, which is characterized by primary magmatic crustal accretion and low-P/T magmatic-arc meta morphism, crustal thickening and high-P/T metamorphism due to convergence and oceanic-arc collision, and high-P/T metamorphism associated with seaward growth of a platemargin accretionary system.

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Contrasting structural styles during polyphase granitoid intrusion, South Victoria Land, Antarctica

Abstract: Four granitoid plutons intruded in the Walcott Bay area, South Victoria Land, during the Paleozoic Ross Orogeny, display markedly different structural styles.

Cited by 8 publications

References 22 publications

Late Sinistral Shearing along Gondwana’s Paleo‐Pacific Margin in the Ross Orogen, Antarctica: New Structure and Age Data from the O’Brien Peak Area

Late Sinistral Shearing along Gondwana’s Paleo‐Pacific Margin in the Ross Orogen, Antarctica: New Structure and Age Data from the O’Brien Peak Area

Structure and timing of transpressional deformation in the Shackleton Glacier area, Ross orogen, Antarctica

Metamorphism in the Ross orogen and its bearing on Gondwana margin tectonics

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