Abstract

• The Silurian rocks in the Kyauktap area comprise seven distinct lithofacies, namely, flat laminated limestone, thin-bedded limestone interbedded with calcareous siltstone, purple phacoidal limestone, whitish grey shale and limestone interbedded unit, medium to thick-bedded limestone interbedded with argillaceous layers, grey phacoidal limestone and Kyauktap graptolite shale. There are nine carbonate microfacies in the Nyaunglwe section, ten microfacies in the Hle Lan section and nine microfacies in the Kyauktap phacoidal section. They are bioclastic rudstone, intraclastic bioclastic packstone, ostracod packstone, ferruginous ostracod packstone, bioclastic wackestone, argillaceous bioclastic wackestone, ferruginous bioclastic wackestone, argillaceous ostracod wackestone, nodular bioclastic wackestone, calcisphere bioclastic wackestone, dolomitized bioclastic wackestone, argillaceous limemudstone, limonitic limemudstone and ferruginous limemudstone. Nyaunglwe section is carbonate dominated unit and Hle Lan section is composed of whitish grey shale and argillaceous limestones in which bioturbated horizons are very common. Kyauktap phacoidal section is entirely grey nodular limestones and it grades into graptolite-bearing grey shales in the southern part of the area. Vertical and lateral variations of the lithofacies and microfacies suggest that the entire Silurian sequence represents a depositional continuum of shallow subtidal, deeper subtidal and slope.