A Study on Apatite from Mesozoic Alkaline Intrusive Complexes, Central High Atlas, Morocco

Abstract

There are abundant phosphate mines in the High Atlas Mountains of Morocco. Gem-quality apatite is produced at the Anemzi deposit, but its associated gem mineralogy is relatively poorly studied. In this study, apatite from the Anemzi mine in Morocco was analysed using standard gemmological characterisation methods, including basic tests (hardness, relative density, microscopy, etc.), spectroscopic tests (infrared, Raman, and ultraviolet–visible spectroscopy), and chemical analyses (electron probe and laser ablation inductively coupled plasma mass spectrometry). This paper explores the gemmological characteristics of Moroccan apatites and the information on diagenesis recorded for apatites by comparing them with apatites from other sources. Apatite from the Anemzi deposit is an igneous fluorapatite. The relatively high Cl content of the apatite suggests that the magma in the area has a high Cl content, whereas the high Cl/F ratio may indicate that the deposit formed in a slab subduction environment. The characteristics of the major and trace elements indicate high oxygen and sulphur escapes in the apatite-forming magma.

Keywords

• apatite
• halogen elements
• Raman spectroscopy
• magmatic oxidation
• LA-ICP-MS