Halstead Road Centenary Pasture

Halstead Road Centenary Pasture is a local nature reserve in Mountsorrel that is owned and managed by Charnwood Borough Council. As you walk across the land you might notice the remnants of medieval ridge and furrow agriculture.

In the middle of the pasture are a set of small rocky outcrops. While this rocks might look like granite, it is in fact slightly different; a granodiorite. The granodiorite has higher amounts of a mineral called plagioclase feldspar, and usually more dark minerals too. Thus it usually has a slightly darker overall colour than a granite.

This rock – the Mountsorrel Granodiorite – was formed when a large mass of molten magma cooled within the crust during the Ordovician geological period, around 450 million years ago. As the molten rock moved through the crust, it sometimes ‘plucked’ off bits of the rock it was flowing past. When the magma cooled, these ‘foreign’ bits of rock were trapped and preserved, and are clearly visible as they often have a grey colour and much smaller crystals/grains than the granodiorite. Can you find any in the outcrops here? These bits of rock incorporated into the granodiorite are called xenoliths.