Lamprophyre from Iona

A Caledonian minor intrusion in western Scotland

118.087 HS [287 kb]

Fig. 1: Photograph of a red lamprophyre from Iona. Sample 118.087, weight, dimensions, magnetic susceptibility, UTM grid location.

"Rock of the Month # 246, posted for December 2021" ---



118.087 PM1 [xxx kb] 118.087 PM2 [xxx kb]

Figs. 2-3: Photomicrographs of a sample of Caledonian lamprophyre from Iona. Sample 118.087 is a fine-grained, granular, holocrystalline lamprophyre which occurs as a narrow dyke. This dyke formed by cooling of magma injected into a brittle fracture which propagated through far-older basement rocks, long before the Tertiary volcanism that dominates the scenery of nearby Mull.

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


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

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 ...

Work of Nick Rock and others on lamprophyres.

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
Minor intrusive -- #246 --- Lamprophyre, Iona, Scotland - "YOU ARE HERE"