Carboniferous limestone with corals
Click the microscope button to view a thin section for this sample.
Click the microscope button to view a thin section for this sample.

Fact sheet

Carboniferous limestone with corals

This Lower Carboniferous limestone comes from the Whitesands and Barns Ness area, South-East of Dunbar, North Berwickshire, Scotland. The rock contains distinctive Koninckophyllum corals and brachiopod shell fragments cemented by a calcium carbonate rich mud known as micrite.

In thin section, the corals are formed of coarse grained sparry calcite and some appear to be linked, note that all the corals in the top left of the section are circular and roughly equidistant from each other indicating they are a life position relative to one another. The larger corals, over 1cm in diameter are variably oriented. Some of the shell and coral fragments are partially filled by fine grained carbonate rich mud, and the remainder of the filling is a sparry calcite. This combination can be used to  determine the orientation of the original rock, or ‘way up’, since the mud would have filled the bottom of the cavity and the cement would have filled the upper part. Such structures are known as geopetal indicators.

Additional images
55.9869, -2.452
The Whitesands and Barns Ness area, Dunbar, Berwickshire
About this collection

The United Kingdom Virtual Microscope (UKVM) collection consists of igneous, sedimentary and metamorphic rocks from around the UK.

It is intended as a teaching resource, helping to tell the story of the common rock types and how they form, and reflecting the history of the UK at the margins of the continent of Europe. The collection is a series of teaching sets, for example igneous rocks from the North Atlantic Igneous Province and SW England; high-temperature metamorphic rocks from Scotland and low-temperature metamorphic rocks from Wales; and sedimentary rocks, including English limestones and sandstones.

Sample details

Rock-forming mineral
Category guide  
Category Guide
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Accessory minerals
Minerals that occur in very low abundance in a rock. They are usually not visible with the naked eye and contribute perhapssver, they often dominate the rare elements such as platinum group metals.
Rock-forming minerals
Minerals that make up the bulk of all rock samples and are also the ones used in rock classi?cation.
Selecting one or more period, for example 'Jurassic'.
A term used to group together related samples that are not already gathered into a single Collection. For instance, there is a ‘SW England granites’ theme that includes such rock types as granite, hydrothermal breccia, skarn and vein samples.
A general term used to label a rock sample. It is a useful way of grouping similar samples throughout a collection. Category names are often, but not exclusively, common rock names (e.g. granite, basalt, dolerite, gabbro, greisen, skarn, gneiss, amphibolite, limestone, sandstone).
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We would like to thank the following for the use of this sample: