Climatic shifts and floristic responses during India’s tectonic voyage from Gondwana to Asia

Abstract

Rising atmospheric carbon dioxide (CO₂) levels are profoundly altering Earth's hydrological systems. To contextualize these changes, insights from past warm intervals are essential. This study synthesizes plant-derived proxy records from the Indian subcontinent to reconstruct hydrological patterns from the Late Cretaceous through the Paleogene—a period marked by India's tectonic drift from Gondwanaland to Asia. Results indicate a persistently warm and humid climate with high mean annual precipitation and pronounced seasonal rainfall from the latest Cretaceous into the early Paleocene. Throughout the early to middle Paleogene, including hyperthermal events such as the PETM, ETM2, and MECO, plant assemblages reflect changes in hydrological cycles and biotic turnover. Notably, these intervals saw a rise in deciduous taxa, signaling heightened seasonality and prolonged dry periods despite global warming. The Early Eocene Climatic Optimum (EECO) stands out for its sustained warm and humid conditions that supported stable tropical evergreen rainforests. The long-standing monsoonal regime observed during Late Cretaceous to early Oligocene more closely resembled the present-day Indonesian–Australian Monsoon than the modern South Asian Monsoon, which likely developed following Himalayan uplift in the Neogene. This synthesis highlights the complex interplay between global warming, seasonal precipitation patterns, and vegetation dynamics, reinforcing India's key role in understanding Cenozoic climate–biosphere evolution.