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CONTENTS

The Asai-Rawas Group distributed in the Asai-Rawas Area, southern Sumatera, is a Jurassic-Cretaceous metasediment sequence. The group is composed of Mid-Late Jurassic Asai Formation, Late Jurassic Mersip Formation, and Late Jurassic-Early Cretaceous Peneta and Rawas Formations. The Asai-Rawas Group from lower to upper parts, comprises alternating meta-sandstone and phyllite showing flysch type succession, with slated and limestone intercalations, of the Asai Fromation; fossiliferous mud-mound limestone of Mersip Formation; alternating siltstone and sandstone, slate, phyllite, shale, and limestone intercalation, of Peneta Formation; and a sequence of meta-sandstone, meta-siltstone, greywacke, pebbly wacke, slate, and limestone and cher intercalations, of Rawas Formation. Sedimentary facies and structure analyses reveal that the rock group developed in a shallow to deep marine environment. Petrographically, clastic sediments of the Asai Formation is predominantly composed of subarkose with minor feldspathic greywacke, in which quartz content is much higher than feldspar. Tectonic setting analysis, based on the QFL and QmFLt plots, shows that provenance of the formation are Craton Interior of Continental Block. The Mersip Formation is made up of fossiliferous mud-mound limestone, containing clay minerals. The presence of clay minerals, especially kaolinite, evidence that limestone deposition was nearby an adjoining continent. Predominantly, the Peneta Formation comprises sublitharenite, with minor subarkose and quartz arenite. Quartz and rock fragments contents are dominant, whereas feldspar is present as a minor content. This formation shows a tectonic provenance of Orogenic Recycled and Quartz Recycled to Transitional Recycled areas, situated in back-arc thrust belt or foreland uplift. However, the southern part displays a slightly different tectonic setting, which is Craton Interior of Continental Block. The Rawas Formatin, situated in the southernmost part of the area, petrographically comprises arkose, subarkose, and lithic arkose, with feldspathic greywacke, greywacke, and quartzite. Provenance analysis shows that the formation is included into Craton Interior, Transitional Continent, and Basement Uplift setting of Continental Block with minor Transitional Arc of Magmatic Arc. In the north, the group shows a suturing contact with the Permian Palepat-Mengkarang Group, whereas, the south, it underlies the Tertiary Volcanics and Sediments.