Kershope Bridge

Also within

Cumbria CountyRoxburgh, Ettrick and Lauderdale County

Condition (Natural England)

Habitats

Fast flowing river and stream

Geology & landscape

Geological Feature: Rock Outcrop · Mining / Industrial: Quarry · Geological Period: Carboniferous · Rock Type: Basalt

Landscape processes: Volcanic / Igneous

Description

Description Kershope Bridge is situated on the Kershope Burn which at this point forms the border between Scotland and England. The site is located two to three kilometres east north east of the small village of Kershopefoot. The geological interest of this site, in technical terms, may be defined as follows: In the Langholm district of the Scottish Borders and in northern Northumberland, the stratigraphy of the Lower Carboniferous is characterised by the occurrence of three groups of volcanic rocks intercalated with sediments of the Northumberland Basin the Birrenswark Volcanic Group, the Kershopefoot Basalt and the Glencartholm Volcanic Beds. The stream section and disused quarry at Kershope Bridge, adjacent to the Anglo Scottish border, furnish the best sections of the series of igneous rocks collectively known as the Kershopefoot Basalts as well as the sediments almost directly above and below. The weight of evidence supports an extrusive origin for the Basalt at this locality. The rock is known to occupy more or less the same stratigraphic horizon over all of its outcrop but may be locally more than one flow. At Kershope Bridge the Basalt is a sporadically and variously felsparphyric olivine basalt with scattered amygdales and drusy cavities containing a variety of infillings. The Kershopefoot Basalt is important in any geochemical or detailed mineralogical study of comparable volcanic rocks in the Midland Valley outcrops of Lower Carboniferous volcanics and, because of its position within the developing Northumberland Basin, it may be considered important in any reconstruction of the crustal evolution and palaeogeography of this part of northern Britain during Permo Carboniferous times. In layman’s terms, the interest of this site may be expressed more simply, this should not be taken as definitive and further information as to details of the interest can be obtained from the Natural England. During the Lower Carboniferous era, a period of geological time some 340 million years ago, the geography of Northern Britain was quite unlike the distribution of land and sea which exists today. Although much of this area was covered by sea, three major landmasses existed in Northern Britain during this time. The Northumberland Basin was bounded by two of these upland areas and much is known about the geological history and development of this feature through detailed study of localities such as Kershope Bridge. Interbedded with the sedimentary rocks which accumulated in this basin are a sequence of thick volcanic lava flows and these together provide detailed information on the environmental conditions existing in this part of Britain during Lower Carboniferous times.

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