Kishonite, VH2, and Oreillyite, Cr2N, Two New Minerals from the Corundum Xenocrysts of Mt Carmel, Northern Israel

Luca Bindi,Jin-Xiang Huang,Fernando Cámara,Sarah E M Gain,William L Griffin,Martin Saunders,Vered Toledo

doi:10.3390/min10121118

Abstract

Here, we describe two new minerals, kishonite (VH2) and oreillyite (Cr2N), found in xenoliths occurring in pyroclastic ejecta of small Cretaceous basaltic volcanoes exposed on Mount Carmel, Northern Israel. Kishonite was studied by single-crystal X-ray diffraction and was found to be cubic, space group Fm3¯m, with a = 4.2680(10) Å, V = 77.75(3) Å3, and Z = 4. Oreillyite was studied by both single-crystal X-ray diffraction and transmission electron microscopy and was found to be trigonal, space group P3¯1m, with a = 4.7853(5) Å, c = 4.4630(6) Å, V = 88.51 Å3, and Z = 3. The presence of such a mineralization in these xenoliths supports the idea of the presence of reduced fluids in the sublithospheric mantle influencing the transport of volatile species (e.g., C, H) from the deep Earth to the surface. The minerals and their names have been approved by the Commission of New Minerals, Nomenclature and Classification of the International Mineralogical Association (No. 2020-023 and 2020-030a).

Highlights

The study of the xenoliths occurring in pyroclastic ejecta of small Cretaceous basaltic volcanoes exposed on Mt Carmel [1,2,3,4,5,6,7,8] has revealed a very peculiar, exotic and ultra-reduced mineral assemblage reflecting the interaction of deep-seated basaltic magmas with mantle-derived CH4 + H2 at high fluid/melt ratios
The sample containing oreillyite was recovered from the Kishon Mid Reach Zone 1 and consists of a 1.7 mm ofcontaining corundumoreillyite with a hollow centre and raised rims, indicating growth, and it Thecrystal sample was recovered from the Kishon
The name kishonite is for the Kishon and it has an intense purple-red colour

Summary

Introduction

The study of the xenoliths occurring in pyroclastic ejecta of small Cretaceous basaltic volcanoes exposed on Mt Carmel [1,2,3,4,5,6,7,8] has revealed a very peculiar, exotic and ultra-reduced mineral assemblage reflecting the interaction of deep-seated basaltic magmas with mantle-derived CH4 + H2 at high fluid/melt ratios. During these ongoing studies, two new minerals, kishonite (VH2 ) and oreillyite (Cr2 N) have been identified and are described here. The University of Western Australia, Australia, catalogue number 1174-C_FF

Description and Physical Properties

Chemical Composition

X-ray Crystallography

Findings

Remarks on the Origin of Kishonite and Oreillyite