Time–space focused intrusion of genetically unrelated arc magmas in the early Paleozoic Ross–Delamerian Orogen (Morozumi Range, Antarctica)

Rocchi, Sergio; Vincenzo, Gianfranco Di; Dini, Andréa; Petrelli, Maurizio; Vezzoni, Simone

doi:10.1016/j.lithos.2015.06.006

Cited by 17 publications

(18 citation statements)

References 70 publications

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“…Thus, we suggest that: (a) the metamorphic zircon growth and/or recrystallization in the eclogite took place episodically at two distinct stages rather than continuously for a prolonged period of c. 15-30 Ma and (b) mantle-rim overgrowth domains of zircon are most likely related to the M 1-2 and M 3 , that is, two discrete events of subduction burial. This temporal scheme of the Lanterman Range eclogite is broadly consistent with the major pulses of preto syn-collisional calcalkaline granitoid emplacement (c. 520-490 Ma for the Granite Harbour Intrusives; Allibone & Wysoczanski, 2002;Bomparola et al, 2007;Giacomini, Tiepolo, Dallai, & Ghezzo, 2007) and the maximum depositional ages (c. 600-530 Ma) of the Wilson metasedimentary rocks (Adams, Bradshaw, & Ireland, 2014;Estrada et al, 2016;Gibson, Morse, Ireland, & Nayak, 2011;Kim, Kim, Lee, & Kim, 2017;Paulsen, Deering, Sliwinski, Bachmann, & Guillong, 2016;Rocchi, Di Vincenzo, Dini, Petrelli, & Vezzoni, 2015). The timing of younger, peak eclogite facies metamorphism (c. 500 Ma) suggests that the final closure of an intervening ocean between the Wilson and Bowers terranes took place in the late Cambrian (e.g.…”

Section: Episodic Zircon Growth and Cyclic Subduction-exhumationsupporting

confidence: 73%

“…520–490 Ma for the Granite Harbour Intrusives; Allibone & Wysoczanski, ; Bomparola et al., ; Giacomini, Tiepolo, Dallai, & Ghezzo, ) and the maximum depositional ages ( c . 600–530 Ma) of the Wilson metasedimentary rocks (Adams, Bradshaw, & Ireland, ; Estrada et al., ; Gibson, Morse, Ireland, & Nayak, ; Kim, Kim, Lee, & Kim, ; Paulsen, Deering, Sliwinski, Bachmann, & Guillong, ; Rocchi, Di Vincenzo, Dini, Petrelli, & Vezzoni, ). The timing of younger, peak eclogite facies metamorphism ( c .…”

Section: Discussionmentioning

confidence: 99%

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P–T evolution and episodic zircon growth in barroisite eclogites of the Lanterman Range, northern Victoria Land, Antarctica

Kim

Cho

et al. 2019

Journal Metamorphic Geology

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Prograde P–T–t paths of eclogites are often ambiguous owing to high variance of mineral assemblages, large uncertainty in isotopic age determinations and/or variable degree of retrograde equilibration. We investigated these issues using the barroisite eclogites from the Lanterman Range, northern Victoria Land, Antarctica, which are relatively uncommon but free of retrogression. These eclogites revealed three stages of prograde metamorphism, defining two distinctive P–T trajectories, M1–2 and M3. Inclusion minerals in garnet porphyroblasts suggest that initial prograde assemblages (M1) consist of garnet+omphacite+barroisite/Mg‐pargasite+epidote+phengite+paragonite+rutile/titanite+quartz, and subsequent M2 assemblages of garnet+omphacite+barroisite+phengite+rutile±quartz. The inclusion‐rich inner part of garnet porphyroblasts preserves a bell‐shaped Mn profile of the M1, whereas the inclusion‐poor outer part (M2) is typified by the outward decrease in Ca/Mg and XFe (=Fe2+/(Fe2++Mg)) values. A pseudosection modelling employing fractionated bulk‐rock composition suggests that the eclogites have initially evolved from ~15 to 20 kbar and 520–570°C (M1) to ~22–25 kbar and 630–650°C (M2). The latter is in accordance with P–T conditions estimated from two independent geothermobarometers: the garnet–clinopyroxene–phengite (~25 ± 3 kbar and 660 ± 100°C) and Zr‐in‐rutile (~650–700°C at 22–27 kbar). The second segment (M3A–B) of prograde P–T path is recorded in the grossular‐rich overgrowth rim of garnet. Apart from disequilibrium growth of the M3A garnet, ubiquitous overgrowth of the M3B garnet permits us to estimate the P–T conditions at ~26 ± 3 kbar and 720 ± 80°C. The cathodoluminescence (CL) imaging of zircon grains separated from a barroisite eclogite revealed three distinct zones with bright rim, dark mantle and moderately dark core. Eclogitic phases such as garnet, omphacite, epidote and rutile are present as fine‐grained inclusions in the mantle and rim of zircon, in contrast to their absence in the core. The sensitive high‐resolution ion microprobe U–Pb dating on metamorphic mantle domains and neoblasts yielded a weighted mean 206Pb/238U age of 515 ± 4 Ma (tσ), representing the time of the M2 stage. On the other hand, overgrowth rims as well as bright‐CL neoblasts of zircon were dated at 498 ± 11 Ma (tσ), corresponding to the M3. Average burial rates estimated from the M2 and M3 ages are too low (<2 mm/year) for cold subduction regime (~5–10°C/km), suggesting that an exhumation stage intervened between two prograde segments of P–T path. Thus, the P–T–t evolution of barroisite eclogites is typified by two discrete episodes with an c. 15 Ma gap during the middle Cambrian subduction of the Antarctic Ross Orogeny.

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Section: Episodic Zircon Growth and Cyclic Subduction-exhumationsupporting

confidence: 73%

Section: Discussionmentioning

confidence: 99%

P–T evolution and episodic zircon growth in barroisite eclogites of the Lanterman Range, northern Victoria Land, Antarctica

Kim

Cho

et al. 2019

Journal Metamorphic Geology

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“…While there is evidence of Grenville-age zircon growth in the Belt Supergroup and adjacent rocks (Doughty and Chamberlain, 2008), there is a dearth of similar-aged granites known north of the Grenville Orogen in 'western' Laurentia (modern position) and in Victoria Land in East Antarctica, and metamorphism in the region of the Belt Supergroup and the corresponding regions in Antarctica appears to have ceased at ca. 1000 Ma (May et al, 2013;Rocchi et al, 2015). Rather, locating the east South Tasman Rise outboard of the southwestern Grenville Orogen, as suggested by Fioretti et al (2005) Mulder et al describe the Rocky Cape Group as a "marine shelfal package."…”

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confidence: 99%

Mesoproterozoic Tasmania: Witness to the East Antarctica–Laurentia connection within Nuna: COMMENT

Moore

Betts

2016

Geology

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“…Closed symbols are from this study. Open symbols and grey bars are 611 previously published data from the following sources: northern Victoria Land: Black and 612 Sheraton, 1990;Bomparola et al, 2006;Fioretti et al, 2005;Rocchi et al, 2015;Tiepolo and 613 Tribuzio, 2008;central Victoria Land: Rocchi et al, 2009; southern Victoria Land: Allibone and Wysoczanski, 2002;Cooper et al, 1997;Cottle and Cooper, 2006a,b;Cox et al, 2000;Encarnación and Grunow, 1996;Hall et al, 1995;Martin et al, 2014;Mellish et al, 2002;Read et al, 2002;Read, 2010;Rowell et al, 1993;Simpson, 2002 Undeformed equigranular granite from the DV2 suite. Photos provided by GNS Science (New Zealand).…”

Section: Discussionmentioning

confidence: 99%

Synchronous alkaline and subalkaline magmatism during the late Neoproterozoic–early Paleozoic Ross orogeny, Antarctica: Insights into magmatic sources and processes within a continental arc

Hagen‐Peter

Cottle

2016

Lithos

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Extensive exposure of intrusive igneous rocks along the Ross orogen of Antarcticaan ancient accretionary orogen on the margin of East Gondwanaprovides an exceptional opportunity to study continental arc magmatism. There is significant petrologic and geochemical variability in igneous rocks within a ~500-km-long segment of the arc in southern Victoria Land. The conspicuous occurrence of carbonatite and alkaline silicate rocks (nepheline syenite, A-type granite, and alkaline mafic rocks) adjacent to large complexes of subalkaline granitoids is not adequately explained by traditional models for continental arc magmatism. Extensive geochemical analysis (>100 samples) and zircon U-Pb geochronology (n = 70) confirms that alkaline and carbonatitic magmatism was partially contemporaneous with the emplacement of large subduction-related igneous complexes in adjacent areas. Major pulses of subalkaline magmatism were compositionally distinct and occurred at different times along the arc. Large bodies of subalkaline orthogneiss and granite (sensu lato) were emplaced over similar time intervals (ca. 25 Myr) to the north (ca. 515-492 Ma) and south (ca. 550-525 Ma) of the alkaline magmatic province, although the onset of these major pulses of magmatism were offset by ca. 35 Myr. Alkaline and carbonatitic magmatism spanned at least ca. 550-509 Ma, overlapping with voluminous subalkaline magmatism in adjacent areas. The most primitive rocks from each area have similarly enriched trace element compositions, indicating some common characteristics of the magma sources along the arc. The samples from the older subalkaline complex have invariably low Sr/Y ratios (<40), consistent with relatively shallow magma generation and differentiation. The younger subalkaline complex and subalkaline rocks within the area of the alkaline province extend to higher Sr/Y ratios (up to ~300), indicative of generation and differentiation at deeper levels. The significant spatial and temporal diversity in magmatism can be explained by a tectono-magmatic model that invokes alternating phases of extension and contraction in the overriding plate. The low Sr/Y magmatism of the earlier subalkaline complex and the largely contemporaneous alkaline and carbonatitic magmatism occurred during a phase of extension in the overriding plate ca. 550-525 Ma. The differences in composition of this early phase of magmatism can be explained by variable lithospheric thickness along the margin, with the alkaline magmas derived from partial melts of thick metasomatized lithosphere. The younger subalkaline complex was emplaced during a phase of contraction in the overlying plate ca. 515-505 Ma. The latest phase of (post-orogenic) magmatism occurred during extension in the overriding plate ca. 505-492 Ma.

show abstract

Time–space focused intrusion of genetically unrelated arc magmas in the early Paleozoic Ross–Delamerian Orogen (Morozumi Range, Antarctica)

Cited by 17 publications

References 70 publications

P–T evolution and episodic zircon growth in barroisite eclogites of the Lanterman Range, northern Victoria Land, Antarctica

P–T evolution and episodic zircon growth in barroisite eclogites of the Lanterman Range, northern Victoria Land, Antarctica

Mesoproterozoic Tasmania: Witness to the East Antarctica–Laurentia connection within Nuna: COMMENT

Synchronous alkaline and subalkaline magmatism during the late Neoproterozoic–early Paleozoic Ross orogeny, Antarctica: Insights into magmatic sources and processes within a continental arc

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