Tertiary (comprising the Palaeogene and Neogene)

The Palaeogene is a geological system that began 66 and ended 23 million years ago and comprises the first part of the Cainozoic Era. Lasting 43 million years, the Palaeogene is most notable as being the time in which mammals evolved from relatively small, simple forms into a large group of diverse animals in the wake of the Cretaceous–Palaeogene extinction event that ended the preceding Cretaceous Period.

This period consists of the Palaeocene, Eocene, and Oligocene Periods. The early part of this period, the Palaeocene, shows evidence of extensive weathering which penetrated deep into the older rocks, for instance on Clee Hill. The end of the Palaeocene (55.5 Ma) was marked by one of the most significant periods of global change during the Cainozoic, the Palaeocene-Eocene Thermal Maximum, which upset oceanic and atmospheric circulation and led to the extinction of numerous deep-sea benthic foraminifera and on land, a major turnover in mammals. The Palaeocene follows the Cretaceous Period and is followed by the Eocene and Oligocene, and then by the Miocene Period.

During the Palaeocene Shropshire experienced significant uplift and the upper levels of the modern day landscape evolved. This was a period of much warmer climatic conditions accompanied by intense subtropical weathering. Remnants of this ancient weathered landscape can still be seen, for instance in Clee Hill quarry where red laterite soil has developed within the underlying thick Carboniferous dolerite sill. This once strong rock is now rotted to a soft soil that can be poked with a finger!

The Neogene is a geological period starting 23 million years ago and ending 2.6 million years ago. The Neogene is subdivided into two periods, the earlier Miocene and the later Pliocene.

The Neogene covers about 20 million years. During this period, mammals and birds continued to evolve into roughly modern forms, while other groups of life remained relatively unchanged. Early hominids, the ancestors of humans, appeared in Africa. Some continental movement took place, the most significant event being the connection of North and South America at the Isthmus of Panama, late in the Pliocene. This cut off ocean currents between the Atlantic and Pacific oceans, causing climate changes and creating the Gulf Stream. The global climate cooled considerably over the course of the Neogene, culminating in a series of continental glaciations in the Quaternary Period that follows.

 

Clee Hill is a Shropshire site with features that originated during the Tertiary.

Clee Hill Quarry from viewpoint
Tertiary timescale