Palaeoecological and palaeoclimate potential of subsurface palynological data from the Late Quaternary sediments of South Kerala Sedimentary Basin, southwest India

摘要

The accrued palynological data obtained from the subsurface sediments of South Kerala Sedimentary Basin have been found to be useful for identifying various ecological complexes and their environmental preferences. The occurrence and relative abundance of Cullenia exarillata pollen along with other wet evergreen forest members at certain intervals are of great significance as they indicate the prevalence of heavy rainfall during Early Holocene. This aspect is further complemented by the presence ofa large number of fungal remains. In contrast, their scarcity and even absence at higher levels in boreholes point towards relatively dry climate during Late Holocene. Another significant aspect of the palynological record is the occurrence of reworkedpollen of Eugeissona ( Arecaceae) and Ctenolophon (Ctenolophonaceae) restricted to one or two intervals in the boreholes, as these forms are common in Miocene sediments of the Warkalli Formation. Increased organic matter in Late Quaternaries may be attributed to relatively higher rates of weathering and erosion of the hinterland as a result of enhanced SW monsoon during Late Pleistocene-Early Holocene. Diatoms and palynodebris, including non-pollen palynomorphs (NPP) observed in palynological preparations are also found to be important for interpretation of the Late Quaternary climate of southwest India.