A melilite-bearing high-temperature calcic skarn, Camasunary Bay, Isle of Skye

Abstract

Synopsis The occurrence of high-temperature calcic skarns is relatively rare, with around 30 being reported worldwide. Here, we report on a newly discovered occurrence of a melilite-bearing high-temperature calcic skarn at Camasunary Bay, Isle of Skye. The contact metamorphism was caused by the intrusion of the Cuillin Hills gabbro and the later intrusion of the Coire Uaigneich granophyre. The calcic skarn consists of a high-temperature assemblage of wollastonite, åkermanite–gehlenite, vesuvianite, tilleyite, spurrite. andradite–grossular garnet, monticellite and perovskite. It also includes the very rare Zr-rich garnet kimzeyite and baghdadite (Ca 3 (Zr,Ti)Si 2 O 9 ), indicating transfer of Zr, Ti and other incompatible element-rich fluids derived from the hydrous Coire Uaigneich granophyre. The calcic skarn contains numerous cherty nodules and stringers, which bear a remarkable resemblance to the Cambrian–Ordovician dolostone exposures observed in other parts of Skye. suggesting that the protolith was originally an impure dolomite. The nature of the contact between the calcic skarn and surrounding Torridonian sedimentary rocks could not be directly observed, but elsewhere on Skye this contact is the Kishorn Thrust plane. This has implications for the simplified tectonic map accompanying the British Geological Survey map of Broadford (Sheet 71W), which now requires modification.

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The application of Raman spectroscopy to djerfisherite identification

“…Djerfisherite, K 6 (Fe,Cu,Ni) 25 S 26 Cl, cubic with space group , a rare K‐ and Cl‐bearing sulfide mineral was first identified in meteorites . Since that time, it has been recognized as an accessory mineral in numerous extreme petrological environments, such as primitive meteorites (anhydrous E chondrites) and achondrites, terrestrial silica‐undersaturated rocks, namely Cu–Ni–sulfide deposits, alkaline igneous complexes and carbonatites, kimberlites and kimberlite‐hosted mantle xenoliths, high‐grade contact marbles and calcic skarn . Djerfisherite is also well known as a daughter phase of melt inclusions in minerals of carbonatites and kimberlites and even as inclusions in diamonds .…”

Kamchatite’ diamond aggregate from northern Kamchatka, Russia:New find of diamond formed by gas phase condensation or chemical vapor deposition

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