Tarr Complex

This complex consists of three bodies of albitite that were intruded into schists, metagreywackes and marbles. They are associated with widespread brecciation and alteration of the country rocks and with small masses of non-sedimentary carbonate rocks (Bentor and Eyal, 1987). Shimron (1975) considered that the carbonate rocks, which cement breccias and form dyke-like bodies up to one metre thick and consist essentially of dolomite and breunnerite, are carbonatites and the alteration, which involved development of actinolite, albite, K-feldspar and phlogopite, is akin to fenitization. However, Bentor and Eyal (1987) are sceptical of the carbonatite interpretation, pointing to low values of Ba, Sr, La and Nb and the abundance of magnesite. An O, Sr and Nd isotope study of the carbonate rocks by Bogoch et al. (1986) concluded that the carbonates were deposited from hydrous fluids but are of mantle origin.