SmoPkin, V.F.: 1992, Komatiitic and picritic
magmatism of the Early Precambrian of the Baltic Shield.
Several workers propose an origin by olivine fractionation and accumulation from picritic
magma (cf., Coleman, 1977; Malpas, 1978; Elthon et al.,1982), while others propose a residual mantle origin (Nicolas and Prinzhofer, 1983; Boudier and Nicolas, 1995; Kelemen et al., 1995; Zhou et al.,1996).
3c) intersected relatively fresh picritic
sills at depths less than 200 m (Stakes and Franklin 1994), and further drilling during ODP Leg 169 sampled sills and basement lavas just south of Bent Hill at depths >430 m (Bjerkgard et al.
The eruptives from MgO-rich (~16%) parental picritic
magma (Krishnamurthy and Cox, 1977) would yield higher platinum group element (PGE) concentrations than typical Deccan basalts and their Cr/Ni ratios are closer to those in the Spanish Caravaca K-T layer than to chondritic ratios (Vannucci et al., 1990; Sutherland, 1994).
The central part of the hill is composed of picritic
leucitite (Hibsch, 1934), whereas the marginal areas consist of basaltic volcanoclastic rocks.
Four suites of mafic rocks are present, namely (1) picritic
lapilli tuff, (2) basaltic to andesitic lapilli tuff, (3) low-Cr basalt, and (4) andesitic basalt.