Palynology of two drilling cores from the Maniamba Basin, Mozambique (Central Gondwana): Insights on age and palaeoenvironments

Abstract

In the present work, dark siltstones, claystones, shales, coals and carbonaceous shale were critically investigated to identify palynofloral assemblages in Mozambiqueʼs overlooked Karoo-aged Maniamba Basin. The study was based on two borehole cores. It unveiled a rich and diversified microflora composed of four distinct palynoassemblages dominated by striate and non-striate bisaccate pollen grains that have prevailed under humid, warm and arid climate conditions in these Gondwana strata. The lower palynoassemblages 1 (P1) and 2 (P2) in both borehole cores are marked by the occurrence of common and abundant striate and non-striate bisaccate pollen, Protohaploxypinus spp., Protohaploxypinus limpidus, Striatopodocarpites cancellatus, Lueckisporites spp., Scheuringipollenites spp. and colpate Cycadopites cymbatus. Late Permian key taxa such as Marsupipollenites triradiatus, Plicatipollenites gondwanensis, and Guttulapollenites hannonicus are found herein. The palynoassemblages 3 (P3) and 4 (P4), were assigned to the Early Triassic based on the FAD of key taxa, chiefly Platysaccus papilonis, Lunatisporites spp., Lundbladispora sp. and Krauselisporites sp. A younger age is assigned to the K5 Formation in the Maniamba Basin correlating well-known Gondwana sequences from the Katberg and Balfour formations from the Main Karoo Basin (South Africa), the Moatize-Minjova Basin (Mozambique), Sakamena Group (Madagascar), Raniganj-Panchet formations (India), Mid-Zambezi valley (Zambia), and the Salt Range Basin (Pakistan). Fossil wood occurrences support the assigned ages. Although other proxies are needed to identify the Permo-Triassic transition, the obtained new palynological data could spark interest in exploring methane associated with coal beds.