Craignurite from the Isle of Mull,

A curious igneous rock from the Tertiary Volcanic District, western Scotland

118.194 HS [287 kb]

Figs. 1: Photograph of a fresh sample of craignurite from Mull. Sample 118.194, weight, dimensions, magnetic susceptibility, UTM grid location.


"Rock of the Month # 245, posted for November 2021" ---

Introduction

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118.194 HS [245 kb] 118.088 HS [302 kb]

Figs. 2-3: Photographs of three samples of craignurite from Mull. Samples 118.193 and 118.194 (left) and 118.088 (right). These rocks are rather enigmatic: the dark, cm-sized rounded masses are possibly akin to pitchstone, in a largely devitrified groundmass. To be investigated shortly... Weights, dimensions, magnetic susceptibility, UTM grid locations...

In prep.: notes & references, plus petrographic notes and photomicrograph(s) from a new thin section.


References

Craig,GY (editor) (1965) The Geology of Scotland. Oliver & Boyd, Edinburgh and London / Archon Books, Hamden, CT, 556pp. plus map.

Emeleus,CH and Gyopari,MC (1992) British Tertiary Volcanic Province. Chapman & Hall, 259pp.

Geological Survey (1957) Geological Survey `Ten-Mile' Map, Sheet One. Geol.Surv.Great Britain, 1:625,000 scale map, Scotland and Northern England, 2nd edition.

Gillen,C (2013) Geology and Landscapes of Scotland. 2nd edition, Terra Publishing, update of 1st edition of 2003, 260pp.

McKirdy,A (2017) Mull, Iona and Ardnamurchan: Landscapes in Stone. Birlinn Ltd, Edinburgh., printed and bound by Latimer Trend, Plymouth. 48pp.

Ordnance Survey ...

Graham Wilson, posted 11 October, 2021

See the Rock of the Month Thematic Index

or, visit the Turnstone "Rock of the Month" Chronological Archives!

Class/Group/Family 11 rocks from Scotland
The "Rock of the Month"
Granite --- #30 --- Ross of Mull granite, Isle of Mull, Scotland
Troctolite --- #31 --- Allivalite, Isle of Rhum, Scotland
Diorite --- #32 --- Appinite, Strontian area, Scotland
Marble --- #51 --- Forsterite marble, Glenelg, Scotland
Marble -- #112 --- Brucite ophicalcite (marble), Isle of Skye, Scotland
Monzonite -- #239 --- Kentallenite, a dark monzonite, Ballachulish area, Scotland
Done, or coming soon, five thin sections in prep. (late 2021):
Volcanic glass -- #242 --- Pitchstones from the Isle of Arran, Scotland
Diabase -- #243 --- Crinanite (analcime olivine dolerite / diabase), Isle of Arran, Scotland
Gabbro -- #244 --- "Old Gabbro" of Ardnamurchan, Scotland
Volcanic / minor intrusive -- #245 --- Craignurite, Isle of Mull, Scotland - "YOU ARE HERE"
Minor intrusive -- #246 --- Lamprophyre, Iona, Scotland