Source and origin of Late Paleozoic dropstones from Peninsular Malaysia: First record of Mississippian glaciogenic deposits of Gondwana in Southeast Asia

Abstract

This study reports several Late Paleozoic dropstone‐bearing formations in Peninsular Malaysia which were not previously investigated. Additionally, the source, formation mechanisms, and correlation to the global Late Paleozoic Ice Age (LPIA) of these dropstones are discussed. Dropstones occur as subrounded to rounded single clasts ranging in size from 0.5 to 20 cm, scattered in red mudstone, black shales, sandstones and shales, and are composed of granite, quartzite, and sandstone. Occurrence of dropstones as rounded, single clasts, and soft‐sediment deformation of the host rock with striations in the dropstones suggest a glaciomarine origin. Precambrian basement rocks and Cambrian–Ordovician quartzite and sandstones are the main sources of the dropstones. Dropstones hosted by shallow‐marine sediments are formed by dropping of clasts from icebergs, while, dropstones present in deep‐marine sediments are formed by dropping of clasts from an ice sheet. The oldest glaciomarine rocks of the Rebak and Chepor members (Singa Formation) can be correlated to the Early Carboniferous global glaciation of the LPIA episode of Gondwana. These sediments are considered as the first record of Lower Carboniferous (Mississippian) glaciomarine rocks in Southeast Asia. However, the glaciomarine deposits of the Kentut and Bukit Raja members (Singa and Kubang Pasu formations, respectively) are correlated with the global Middle Carboniferous glaciation. In addition, the glaciomarine deposits of the “undifferentiated” member (Kubang Pasu Formation), Ulang and Selang members (Singa Formation), as well as the Kenny Hill Formation, are correlative to the Late Carboniferous‐Early Permian glaciation episode known as the apex of the LPIA. These results confirm the paleomagnetic and paleontological data which suggest that the Sibumasu Terrane initially was attached to the Late Paleozoic Gondwana.