10.6084/m9.figshare.3454595.v1
Leone Melluso
Leone
Melluso
Hetu C. Sheth
Hetu C.
Sheth
John J. Mahoney
John J.
Mahoney
Vincenzo Morra
Vincenzo
Morra
Chiara M. Petrone
Chiara M.
Petrone
Michael Storey
Michael
Storey
Correlations between silicic volcanic rocks of the St Mary's Islands (southwestern India) and eastern Madagascar: implications
for Late Cretaceous India–Madagascar reconstructions
Geological Society of London
2016
St Mary
Cretaceous
reconstruction
rhyolite
Nd
ppm
Sr
silicic
Madagascar
Vatomandry
chemical
province
Geology
2016-06-21 12:13:57
Dataset
https://geolsoc.figshare.com/articles/dataset/Correlations_between_silicic_volcanic_rocks_of_the_St_Mary_s_Islands_southwestern_India_and_eastern_Madagascar_implications___for_Late_Cretaceous_India_Madagascar_reconstructions/3454595
<p>The St Mary's Islands (southwestern India) expose silicic volcanic and sub-volcanic rocks (rhyolites and granophyric dacites)
emplaced contemporaneously with the Cretaceous igneous province of Madagascar, roughly 88–90 Ma ago. The St Mary's Islands
rocks have phenocrysts of plagioclase, clinopyroxene, orthopyroxene and opaque oxide, moderate enrichment in the incompatible
elements (e.g. Zr = 580–720 ppm, Nb = 43–53 ppm, La/Yb<sub>n</sub> = 6.9–7.2), relatively low initial <sup>87</sup>Sr/<sup>86</sup>Sr (0.7052–0.7055) and near-chondritic initial <sup>143</sup>Nd/<sup>144</sup>Nd (0.51248–0.51249). They have mineral chemical, whole-rock chemical and isotopic compositions very close to those of rhyolites
exposed between Vatomandry–Ilaka and Mananjary in eastern Madagascar, and are distinctly different from rhyolites from other
sectors of the Madagascan province. We therefore postulate that the St Mary's and the Vatomandry–Ilaka–Mananjary silicic rock
outcrops were adjacent before the Late Cretaceous rifting that split Madagascar from India. If so, they provide a valuable
tool to check and aid traditional Cretaceous India–Madagascar reconstructions based on palaeomagnetism, matching Precambrian
geological features, and geometric fitting of continental shelves.
</p>