Chloritoid Schist - Arran
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

Chloritoid Schist - Arran

This rock was deposited in the late Proterozoic period, probably as a series of silts and muds, before being subject to regional metamorphism in the Grampian orogeny. It now forms part of the Dalradian succession in Scotland within the chloritoid zone; Barrovian metamorphic zone (Barrow zones include chlorite-biotite-garnet-staurolite-kyanite-sillimanite). This samples comes from an area adjacent to The Craw, Catacoul bay, the Isle of Arran, Scotland.

The thin section illustrates the folded metasedimentary banding, with fine grained quartz, muscovite, and chlorite. Large porphyroblasts of chloritoid exhibit greenish brown/blue pleochroism, blocky shapes and poor cleavage. There are also books of chlorite visible at the edges of the chloritoid infilling pressure shadows. Chlorite exhibits green colours and and strong cleavage and between crossed polars it has anomalous blue/brown birefringence colours.

Map
 
55.6819, -5.3347
Description:
The Craw, Catacol, Isle of Arran, Scotland
Precision:
Good
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
metamorphic
Category
schist
Rock-forming mineral
chloritoid
muscovite
chlorite
quartz
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:

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UK Virtual Microscope