The Falkland Islands: New Palaeomagnetic Data and their Origin as a Displaced Terrane from Southern Africa

Author(s):  
Graeme K. Taylor ◽  
John Shaw
2021 ◽  
pp. SP518-2021-44
Author(s):  
M. A. Morake ◽  
J. N. F. O'Kennedy ◽  
M. W. Knoper ◽  
M. de Kock ◽  
J. D. Kramers ◽  
...  

AbstractNew 40Ar/39Ar data from dykes intruded into Sverdrupfjella and Ahlmanryggen, Dronning Maud Land, Antarctica, indicate that dyke emplacement commenced at ca. 207 Ma and lasted until ca. 178 Ma. Whereas the ages ascribed to the Karoo-age magmatism contributing to Gondwana breakup are typically inferred as being ca. 182 Ma, the data indicate that ages older than ca.192 Ma in the broader Karoo Province are restricted to western Dronning Maud Land, Antarctica, indicating the locality where break-up was initiated. Limited palaeomagnetic data from ca. 178-185 Ma dykes combined with published palaeomagnetic data from similar aged dykes in Vestfjella and the Ferrar Province, suggest that Antarctica had already drifted/rifted significantly away from southern Africa from ca. 207 Ma to ca. 180 Ma, earlier than previously thought. The data, if correct, require a re-evaluation of the ages ascribed to ocean-floor anomalies used to constrain reconstructions of Gondwana and may provide insight into the history of microcontinental blocks including the Falkland Islands, Haag nunataks, Ellsworth-Whitmore block and Maurice Ewing Bank.Supplementary material at https://doi.org/10.6084/m9.figshare.c.5612838


2019 ◽  
Vol 56 (9) ◽  
pp. 912-916
Author(s):  
Michael E. Evans ◽  
Adrian R. Muxworthy

Vaalbara is the name given to a proposed configuration of continental blocks—the Kaapvaal craton (southern Africa) and the Pilbara craton (north-western Australia)—thought to be the Earth’s oldest supercraton assemblage. Its temporal history is poorly defined, but it has been suggested that it was stable for at least 400 million years, between 3.1 and 2.7 Ga. Here, we present an updated analysis that shows that the existence of a single supercraton between ∼2.9 and ∼2.7 Ga is inconsistent with the available palaeomagnetic data.


2016 ◽  
Vol 13 (3) ◽  
pp. 359-376 ◽  
Author(s):  
Tiffany L Green ◽  
Amos C Peters

Much of the existing evidence for the healthy immigrant advantage comes from developed countries. We investigate whether an immigrant health advantage exists in South Africa, an important emerging economy.  Using the 2001 South African Census, this study examines differences in child mortality between native-born South African and immigrant blacks.  We find that accounting for region of origin is critical: immigrants from southern Africa are more likely to experience higher lifetime child mortality compared to the native-born population.  Further, immigrants from outside of southern Africa are less likely than both groups to experience child deaths.  Finally, in contrast to patterns observed in developed countries, we detect a strong relationship between schooling and child mortality among black immigrants.


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