Basalt with spinel lherzolite xenolith
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Fact sheet

Basalt with spinel lherzolite xenolith

This sample is a xenolith from within a basalt lava flow, brought up from between 30 and 90 km beneath the Earth's surface from deep within the upper part of the Earth's mantle. The lava was erupted during the Carboniferous period, in an area of the Midland valley that was often beneath sea level and saw limestone deposition. The rock comes from Hillhead Quarry, Dundonald, Ayrshire, Scotland, which was created to produce aggregate for roads. The quarry is also known for the prominent columnar jointing in a thick basalt flow.

The thin section exhibits both the xenolith and encompassing basalt. The basalt contains a randomly oriented network of plagioclase grains with pyroxene and relatively unaltered olivine crystals. However some of the olivine grains may actually be fragments of the xenolith. On the left of the thin section plagioclase is absent and the lithology is dominated by coarse-grained olivine and spinel. Much of the olivine is fractured but not strongly altered, and fracturing is more pronounced towards the edge of the xenolith.

Additional images
  • xenolith in basalt - width 2.5 cm
55.5719, -4.6242
Hillhead quarry, Ayrshire, Scotland
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).
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: