Early Mesoproterozoic arc magmatism followed by early Neoproterozoic granulite facies metamorphism with a near-isobaric cooling path at Mount Brown, Princess Elizabeth Land, East Antarctica

Liu, Xiaochun; Wang, Wei-; Zhao, Yue; Liu, Jian; Hong, Chen; Cui, Yingchun; Song, Biao

doi:10.1016/j.precamres.2016.08.003

Cited by 27 publications

(26 citation statements)

References 68 publications

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“…Scarce outcrop between Prydz Bay (~78°E) and Cape Harrison (~99°E) is poorly studied, but recent geochronology from Mt Brown (~86°E), Gaussberg (~89°E) and Mirny station (~93°E) yields 980–920 Ma U-Pb zircon ages 39 , 40 , characteristic of the onshore Rayner province (e.g., Boger 9 and references therein) and its offshore detritus (Fig. 2 ).…”

Section: Discussionmentioning

confidence: 99%

A cryptic Gondwana-forming orogen located in Antarctica

Daczko

Halpin

Fitzsimons

et al. 2018

Sci Rep

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The most poorly exposed and least understood Gondwana-forming orogen lies largely hidden beneath ice in East Antarctica. Called the Kuunga orogen, its interpolation between scattered outcrops is speculative with differing and often contradictory trends proposed, and no consensus on the location of any sutures. While some discount a suture altogether, paleomagnetic data from Indo-Antarctica and Australo-Antarctica do require 3000–5000 km relative displacement during Ediacaran-Cambrian Gondwana amalgamation, suggesting that the Kuunga orogen sutured provinces of broadly Indian versus Australian affinity. Here we use compiled data from detrital zircons offshore of East Antarctica that fingerprint two coastal subglacial basement provinces between 60 and 130°E, one of Indian affinity with dominant ca. 980–900 Ma ages (Indo-Antarctica) and one of Australian affinity with dominant ca. 1190–1140 and ca. 1560 Ma ages (Australo-Antarctica). We combine this offshore compilation with existing and new onshore U-Pb geochronology and previous geophysical interpretations to delimit the Indo-Australo-Antarctic boundary at a prominent geophysical lineament which intersects the coast east of Mirny at ~94°E.

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Section: Discussionmentioning

confidence: 99%

A cryptic Gondwana-forming orogen located in Antarctica

Daczko

Halpin

Fitzsimons

et al. 2018

Sci Rep

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“…1,347 to 1,020 Ma, indicating long‐lived magmatic accretion within the composite Rayner continental arc. Thus, aeromagnetic surveys over Princess Elizabeth Land image the extent of a continuous Stenian‐age accretional orogen in East Antarctica, which preserves geological records of a protracted accretionary history prior to collision (Liu et al, ; Mikhalsky et al, ). The prominent Robertson Magnetic Anomaly (Figure ; Golynsky, Masolov, et al, ) reflects amphibolite facies rocks that only crop out at Robertson Nunatak (Figure ; Mikhalsky et al, ).…”

Section: Examples Of the Compilation's Geological Significancementioning

confidence: 77%

New Magnetic Anomaly Map of the Antarctic

Golynsky

Ferraccioli

Hong

et al. 2018

Geophysical Research Letters

104

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The second generation Antarctic magnetic anomaly compilation for the region south of 60°S includes some 3.5 million line-km of aeromagnetic and marine magnetic data that more than doubles the initial map's near-surface database. For the new compilation, the magnetic data sets were corrected for the International Geomagnetic Reference Field, diurnal effects, and high-frequency errors and leveled, gridded, and stitched together. The new magnetic data further constrain the crustal architecture and geological evolution of the Antarctic Peninsula and the West Antarctic Rift System in West Antarctica, as well as Dronning Maud Land, the Gamburtsev Subglacial Mountains, the Prince Charles Mountains, Princess Elizabeth Land, and Wilkes Land in East Antarctica and the circumjacent oceanic margins. Overall, the magnetic anomaly compilation helps unify disparate regional geologic and geophysical studies by providing new constraints on major tectonic and magmatic processes that affected the Antarctic from Precambrian to Cenozoic times.Plain Language Summary Given the ubiquitous polar cover of snow, ice, and seawater, the magnetic anomaly compilation offers important constraints on the global tectonic processes and crustal properties of the Antarctic. It also links widely separated areas of outcrop to help unify disparate geologic studies and provides insights on the lithospheric transition between Antarctica and adjacent oceans, as well as the geodynamic evolution of the Antarctic lithosphere in the assembly and breakup of the Gondwana, Rodinia, and Columbia supercontinents and key piercing points for reconstructing linkages between the protocontinents. The magnetic data together with ice-probing radar and gravity information greatly facilitate understanding the evolution of fundamental large-scale geological processes such as continental rifting, intraplate mountain building, subduction and terrane accretion processes, and intraplate basin formation.

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“…Both of the resulting mineral assemblages formed during a single Grenville-aged metamorphic cycle, as evidenced by the fact that some zircon grains located in areas of retrograde reaction textures in paragneisses also yield early Neoproterozoic ages (Liu et al 2016). The following three lines of evidence support this assumption: 1) the compositions of stage I garnet increase in grossular contents towards garnet rims that have compositions similar to stage II garnet (Liu et al 2016), indicating that they record a continuous metamorphic process, 2) petrographic observations indicate that the globular beads of monazite with c. 670-630 Ma ages grew after the formation of the coronal and symplectitic minerals, and 3) the new growth of monazite at c. 580-500 Ma did not occur in areas with symplectitic textures that formed at higher P-T conditions of 760-830°C and 7.0-8.5 kbar (Liu et al 2016). This demonstrates that no metamorphic reactions occurred in these rocks after the Grenville-aged metamorphic event.…”

Section: Discussionmentioning

confidence: 99%

“…Mafic granulite sample MB04-8 has a coarse-grained primary assemblage of garnet + orthopyroxene + clinopyroxene + hornblende + biotite + plagioclase + quartz + ilmenite + magnetite ( Fig. 3d), as well as a locally developed fine-grained secondary assemblage of garnet + clinopyroxene + hornblende + biotite + plagioclase + quartz + ilmenite + magnetite, as described by Liu et al (2016). The lithologies, mineral assemblages and ages of the studied samples are summarized in Table I.…”

mentioning

confidence: 89%

“…500 Ma, suggesting that the coastal part of this area was affected by the Pan-African-aged event (Mikhalsky et al 2015). However, no new zircon growth or Pb loss associated with this event has been identified within high-grade rocks from Mount Brown (Mikhalsky et al 2015, Liu et al 2016). This led Mikhalsky et al (2015) to suggest that the Pan-African-aged tectonothermal event became weaker towards inland areas.…”

Section: Introductionmentioning

confidence: 98%

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The impact of the Pan-African-aged tectonothermal event on high-grade rocks at Mount Brown, East Antarctica

Liu

et al. 2020

Antarctic Science

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This study presents monazite and rutile U–Pb and hornblende and biotite 40Ar/39Ar geochronological data for high-grade rocks of the eastern Grenville-aged Rayner orogen at Mount Brown in order to analyse the extent and degree of Pan-African-aged reworking. Monazite from paragneiss yields U–Pb ages of 910 Ma for larger granular grains and 670–630 Ma for smaller globular beads around garnet porphyroblasts or hosted by symplectites. Rutile from leucogneiss yields U–Pb ages of 520–515 Ma. Hornblende and biotite from different rock types yield 40Ar/39Ar plateau ages of 744 and 520–505 Ma, respectively. Combining these results with published zircon U–Pb age data suggests that granulite facies metamorphism occurred at 910 Ma, with a local low-temperature fluid flow event at 670–630 Ma and thermal reworking at 520–505 Ma. The older age of 744 Ma may reflect cooling or partial resetting of the hornblende 40Ar/39Ar system, indicating that Pan-African-aged reworking did not exceed temperatures much higher than the hornblende Ar closure temperature. These data also suggest that the complete isotopic resetting of some minerals may occur without the growth of new mineral phases, providing an example of the style of reworking that is likely to occur in polymetamorphic terranes.

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Early Mesoproterozoic arc magmatism followed by early Neoproterozoic granulite facies metamorphism with a near-isobaric cooling path at Mount Brown, Princess Elizabeth Land, East Antarctica

Cited by 27 publications

References 68 publications

A cryptic Gondwana-forming orogen located in Antarctica

A cryptic Gondwana-forming orogen located in Antarctica

New Magnetic Anomaly Map of the Antarctic

The impact of the Pan-African-aged tectonothermal event on high-grade rocks at Mount Brown, East Antarctica

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