Geochemical and paleomagnetic characteristics of Vestfold Hills mafic dykes in Prydz Bay region: implications on the Paleoproterozoic connection between East Antarctica and proto-India

2021 ◽  
pp. SP518-2021-33
Author(s):  
Manoj K. Pandit ◽  
Anthony Pivarunas ◽  
Joseph G. Meert

AbstractThe Archean age granite gneiss basement along the Prydz Bay coastline in East Antarctica hosts N-S, E-W, NE-SW, and NW-SE trending mafic dyke swarms in the Vestfold Hills region that intruded between 2420 and 1250 Ma. The dyke trends do not show a direct correlation with the dyke geochemistry but can be broadly discriminated into high-Mg and Fe-rich tholeiites. The former type being more siliceous, LILE, HFSE, and LREE enriched, crystallized from a fractionated melt with a notable crustal component or fluid enrichment through the previous subduction process. The Fe-rich tholeiites are less siliceous, have lower abundances of LILE and REE, and were derived from an undifferentiated, primitive melt. The geochemical characteristics of both types underline a shallow level and a high degree of melting in the majority of cases, and a broadly Island Arc Basalt (IAB) affinity. Paleomagnetic analysis of hand samples shows directional groups consistent with geochemical groupings. The Vestfold Hills dykes show a possible linkage with the coeval mafic dykes in Eastern Dharwar and Bastar cratons of the South Indian Block, based on the similarity in the Paleoproterozoic paleolatitudes.

2007 ◽  
Vol 19 (1) ◽  
pp. 97-106 ◽  
Author(s):  
Frank Lisker ◽  
Christopher J.L. Wilson ◽  
Helen J. Gibson

Analysis of five basement samples from the Vestfold Hills (East Antarctica) reveals pooled apatite fission track (FT) ages ranging from 188 to 264 Ma and mean lengths of 13.7 to 14.9 μm. Quantitative thermal histories derived from these data give consistent results indicating onset of cooling/denudation began sometime prior to 240 Ma, with final cooling below 105°–125°C occurring between 240 and 220 Ma (Triassic). A Cretaceous denudation phase can be inferred from the sedimentary record of the Prydz Bay offshore the Vestfold Hills. The two denudational episodes are likely associated with Palaeozoic large-scale rifting processes that led to the formation of the adjacent Lambert Graben, and to the Cretaceous Gondwana break-up between Antarctica and India. Subsequent evolution of the East Antarctic passive continental margin likely occurred throughout the Cenozoic based on the depositional record in Prydz Bay and constraints (though tentative) from FT data.


1990 ◽  
Vol 17 (3) ◽  
pp. 256-261 ◽  
Author(s):  
Eric J. Woehler

The minimum total breeding seabird biomass in the Australian Antarctic Territory was estimated to be 9,971.1 t, dominated by Emperor Penguins, 3,863 t (38.7%) and Adélie Penguins, 5,825 t (58.4%). The 5° sector between 75°E and 80°E, in south-east Prydz Bay, held 35% of the total AAT seabird biomass. Prydz Bay has been shown to be an area of high productivity, and the concentration of seabird biomass in this area reflects the high biomass of prey species and the availability of nesting habitat in the Vestfold Hills, a large ice-free area adjacent to Prydz Bay. Activities associated With research stations are believed to be the only factors that have impacted on breeding seabird populations to date, but minerals activities, tourism and support facilities, and a Krill fishery, are future conservation issues that will have an impact on this major concentration of seabird biomass in East Antarctica.


2019 ◽  
Vol 329 ◽  
pp. 273-293 ◽  
Author(s):  
Evgenii V. Mikhalsky ◽  
Nikolay L. Alexeev ◽  
Igor A. Kamenev ◽  
Mikhail S. Egorov ◽  
Evgenii L. Kunakkuzin

1994 ◽  
Vol 6 (3) ◽  
pp. 379-394 ◽  
Author(s):  
John P. Sims ◽  
Paul H. G. M. Dirks ◽  
Chris J. Carson ◽  
Chris J. L. Wilson

Archaean gneisses in the Rauer Group of islands, East Antarctica, record a prolonged history of high-grade deformational episodes, many of which predate that identified in mid-Proterozoic gneisses. Eleven generations of mafic dykes, belonging to discrete chemical suites, have been used as relative time markers to constrain this deformational history. Based on the timing of intrusion with respect to structures, dykes in the Rauer Group have been correlated with largely undeformed and dated dyke suites in the adjacent Vestfold Hills. This has allowed absolute ages to be inferred for the early- to mid-Proterozoic mafic dyke suites in the Rauer Group, and a correlation of the interspersed structural events. Most structures in the Rauer Group, however, developed in response to high-grade progressive deformation at approximately 1000 Ma. During this deformational episode, strains were repeatedly partitioned into sub-vertical, noncoaxial, high-strain zones recording NW-directed sinistral transpression, that separated zones of lower strain dominated by coaxial folding with axes parallel to the shear direction. Three additional mafic dyke suites intruded during this deformation which was followed by three stages of brittle-ductile deformation and a final suite of lamprophyre dykes. Due to the numerous intrusive time markers, the Rauer Group serves as an excellent illustration of how complicated gneiss terrains may be.


Author(s):  
Steven K. Spreitzer ◽  
Jesse B. Walters ◽  
Alicia Cruz‐Uribe ◽  
Michael L. Williams ◽  
Martin G. Yates ◽  
...  

2016 ◽  
Vol 219 ◽  
pp. 528-536 ◽  
Author(s):  
Rui Xue ◽  
Ling Chen ◽  
Zhibo Lu ◽  
Juan Wang ◽  
Haizhen Yang ◽  
...  

2020 ◽  
Author(s):  
Chengyan Liu ◽  
Zhaomin Wang ◽  
Robin Robertson ◽  
Chen Cheng ◽  
Xi Liang ◽  
...  

2021 ◽  
Vol 36 (4) ◽  
Author(s):  
Emily J. Tibbett ◽  
Howie D. Scher ◽  
Sophie Warny ◽  
Jessica E. Tierney ◽  
Sandra Passchier ◽  
...  

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