Kaersutite theralite - Lugar sill
Collection:
UK Virtual Microscope
Click the microscope button to view a thin section for this sample.
Microscope
Click the microscope button to view a thin section for this sample.
Microscope

Fact sheet

Kaersutite theralite - Lugar sill

This sample derives from the 49m thick Lugar sill in Ayreshire, Scotland, an alkaline sill intruded around 288 million years ago during the Carboniferous period. The sill was intruded as at least four separate phases (indicated by marginal chilling between the bands) ranging in composition from theralite passing down into kaersutite theralite and then picrite. It is thought that the magmas were produced in a deeper magma chamber by differentiation of a mantle-derived, alkali-rich picritic magma. The site is a protected Site of special Scientific Interest (SSSI).

The thin section contains large blades of brown pleochroic kaersutite amphibole, end sections of which exibit 120 degree amphibole cleavage. There are also many tabular plagioclase grains showing some alteration. Pale coloured nepheline and analcime are also present and exhibit low birefringence colours. Altered pyroxene was probably originally titan augite.

Map
 
55.4666, -4.2166
Description:
Lugar Sill, Ayreshire, Scotland
Precision:
Moderate
About this collection
 
UK Virtual Microscope

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

Collection: UK Virtual Microscope
Type
igneous
Category
theralite
Rock-forming mineral
kaersutite
amphibole
plagioclase
feldspar
Category guide  
Category Guide
Title
Refers to any word or phrase that appears in the individual rock names. Names are generally descriptive; they allow users to search for broad terms like ‘granite’ as well as more specific names such as ‘breccia’. However, the adjacent descriptions of the specimens captures a wider range of general words and phrases and is a more powerful search tool.
Description
Refers to any word or phrase that appears anywhere in the descriptions of the specimens
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.
Timescale
Selecting one or more period, for example 'Jurassic'.
Theme
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.
Category
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).
Owner
The owner of the sample that appears in the collection. For example, NASA owns all the samples that appear in the Moon Rocks collection
We would like to thank the following for the use of this sample:

More from this collection

UK Virtual Microscope