The Madai-Baturong Limestone in eastern Sabah and its new interpretation as a seamount

Abstract

The shallow marine Lower Cretaceous Madai-Baturong Limestone of east Sabah is surrounded by deep water ophiolitic rocks such as cherts, turbiditic greywackes and spilitic basalts belonging to the Chert-Spilite Formation. A new interpretation that it is a seamount carbonate is proposed because of: the extreme purity of the carbonates and the lack of terrigenous detrital inputs into the limestone, its intimate relationship with the surrounding typical deep water ophiolitic rocks, and its large size and yet limited lateral extend. The development of fissures filled with younger Upper Cretaceous limestone breccias with volcanic input in its matrix enclosing blocks of the older limestone indicating exposure and erosion of the top of the limestone which must have remained near the paleosea-Ievellends further support to the hypothesis. The smaller limestone bodies interbedded with the Chert-Spilite Formation rocks could be blocks which have slumped off the topographically higher seamounts into the deeper parts surrounding them.