Inverbrora

Also within

Sutherland County

Condition (NatureScot)

Climate exposure

This is about exposure to a nationwide pressure this habitat type carries — not a verdict on this site's own management.

Habitats

Fast flowing river and stream

Geology & landscape

Geological Feature: Floodplain · Geological Period: Jurassic · Rock Type: Limestone, Sandstone

Landscape processes: Coastal, Fluvial

Description

INVERBRORA Inverbrora Site of Special Scientific Interest (SSSI) is located near Brora on the east coast of Sutherland. The site is in three parts: two on the banks of the River Brora, the other on the foreshore near the outflow of the River Brora. The site contains nationally important exposures of middle-late Jurassic rocks which were originally deposited as sediments between 168 and 156 million years ago. These rocks are split geologically into three time periods: Bathonian, Callovian and Oxfordian, spanning some 30 million years. The site makes an important contribution to our understanding of the geography and environmental conditions that existed in the Moray Firth Basin in middle-late Jurassic times. The site is also nationally important for the abundant fossilised plant remains. The Bathonian rocks (168-165 million years old) are found south of Brora. These rocks include the Brora Coal Formation, a sequence of river-deposited sandstones overlain by floodplain mudstones and deposits from a lagoon environment periodically invaded by the sea. The deposits also include thin layers of coal, bituminous shales and some shell-rich beds. This is the only extensive exposure of rock of this age in eastern Scotland. It is also the only onshore exposure of rocks equivalent to the oil-bearing sandstones found beneath the Moray Firth and the North Sea. The exposures of Callovian rocks (165-161 million years old) seen at Brora are the most complete and accessible in the Moray Firth Basin. This is the type locality (the place where a type of rock was first found and described) for the Brora Argillaceous Formation and the Brora Arenaceous Formation. These rocks were formed in a near-shore marine environment and are important for palaeogeographical studies. They contain a rich fossil mollusc fauna including marine gastropods, bivalves and belemnites. The site is the type locality for a number of ammonite and bivalve species. The site also includes reference sections for all the layers of rock in the Upper Callovian for which definite dates have been measured. The Oxfordian section (161-156 millions years old) is well exposed here and shows a junction between the Oxfordian and the underlying Callovian. This exposure shows a type section of both the Brora Sandstone Member and the Ardassie Limestone Member. The Ardassie Limestone Member has a carbonate character unique to Scotland, with an unparalleled ammonite fauna. Mesozoic Palaeobotany The Bathonian age Brora Coal Formation yields fossil plant remains, such as ferns and conifers, which comprise the youngest Jurassic flora in the Moray Firth Basin. Although the majority of these remains are broken fragments, they are nevertheless very well-preserved, showing great detail of their structure. The site has not been fully researched to date, and has great potential for future work.

Plant communities