India’s Northward Drift from Gondwana to Asia During the Late Cretaceous-Eocene

Abstract

The northward drift of the Indian plate from its original Gondwana home in the late Jurassic to its current position in Asia
since the Early Cenozoic provides a unique natural laboratory for tracking its changing geography, climate, tectonics, and
biotic evolution for the past nearly 150 million years. With the breakup of Gondwana, India began to disintegrate into a
smaller plate, becoming partially isolated during the Early Cretaceous Period, but possibly retaining a biotic link with Africa
via Madagascar. Around 80 Ma, as the Indian plate collided with the Kohistan-Ladakh (KL) Arc and Arabia collided with
the Oman Arc, a continuous accreted terrane - the Oman-Kohistan-Ladakh (OKL) Arc- was formed that possibly served as
a biotic filter bridge between India and Africa. The biotic connectivity with Africa and South America helps to resolve a
major conundrum of Indian paleobiogeography, namely the lack of endemism among Late Cretaceous Indian tetrapods.
Later, two catastrophic events at the Cretaceous-Paleogene (K/Pg) boundary, with possible links to the dinosaur extinction,
marked the terminal phase of India’s northward drift. The Deccan volcanism and the possible Shiva impact. Around the
same time, Seychelles was separated from India. During the Late Cretaceous (~67 Ma), the Indian plate suddenly accelerated
its motion to 20 cm/year between two transform faults that facilitated its northward movement: the Owen-Chaman Fault
on the west and the Wharton Ridge-Sagaing Fault on the east. As a result, the Neotethyan plate, bordered by these two
transform faults, became a separate oceanic plate (Kshiroda plate). India continued its acceleration during the Paleocene as
a passenger ship with a mobile gangplank of the OKL Arc, carrying its impoverished Gondwanan fauna. A pronounced
global warming took place during the Paleocene-Eocene Thermal Maximum (PETM), when India collided with Asia causing
significant changes to tectonics and tetrapod radiation. India slowed down dramatically to 5 cm/year during its initial
collision, and its tetrapod fauna underwent an explosive evolution in response to a new ecological opportunity resulting in
the Indo-Eurasian interchanges. The occurrence of several stem groups of tetrapods supports the Gondwanan Indian origin
(i.e. the Out-of-India hypothesis) of several modern mammal orders such as the perissodactyls, primates, artiodactyls and
whales whose antiquity can now be traced phylogenetically to the Indian taxa.