Publication Date:
2021-05-19
Description:
The Laccadive–Chagos Ridge and Southern Mascarene Plateau
in the north-central and western Indian Ocean, respectively,
are thought to be volcanic chains formed above the Réunion
mantle plume1 over the past 65.5 million years2,3. Here we use
U–Pb dating to analyse the ages of zircon xenocrysts found
within young lavas on the island of Mauritius, part of the
Southern Mascarene Plateau. We find that the zircons are
either Palaeoproterozoic (more than 1,971 million years old)
or Neoproterozoic (between 660 and 840 million years old).
We propose that the zircons were assimilated from ancient
fragments of continental lithosphere beneath Mauritius, and
were brought to the surface by plume-related lavas. We
use gravity data inversion to map crustal thickness and
find that Mauritius forms part of a contiguous block of
anomalously thick crust that extends in an arc northwards
to the Seychelles. Using plate tectonic reconstructions, we
show that Mauritius and the adjacent Mascarene Plateau may
overlie a Precambrian microcontinent that we call Mauritia.
On the basis of reinterpretation of marine geophysical data4,
we propose that Mauritia was separated from Madagascar
and fragmented into a ribbon-like configuration by a series of
mid-ocean ridge jumps during the opening of the Mascarene
ocean basin between 83.5 and 61 million years ago.We suggest
that the plume-related magmatic deposits have since covered
Mauritia and potentially other continental fragments.
Description:
PDF is Published online 23 Feb 2013 version
Description:
Published
Keywords:
Palaeomagnetism
;
Petrology
;
Tectonics
;
Volcanology
;
Zircon
Repository Name:
AquaDocs
Type:
Journal Contribution
,
Refereed
Format:
pp.223-227
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