Constructional features of the Troodos ophiolite and implications for the distribution of orebodies and the generation of oceanic crust: Discussion

Abstract

It is not important whether these rocks end up being called members of the sanukitoid suite. What is important is understanding why certain Archean calc-alkaline rocks tend to have higher Ni and Cr contents and are thus more primitive than most modem calc-alkaline rocks. We need to be able to distinguish the intermediate to siliceous rocks with high Ni, Cr, and LILE abundances and high Mg#'s from other calcalkaline rocks, evaluate their abundance, and determine their origin, because they may be an important ingredient in the evolution of the continental crust. We recommend the use of the term sanukitoid suite, because giving this suite of rocks an unambiguous name-whatever the name-helps us to distinguish, describe, and discuss them. KOTO, B. 1916. On the volcanoes of Japan, part V. Journal of the Geological Society of Japan, 23: 95-127. NIELSEN, R. L. 1985. EQUIL: a program for the modeling of low-pressure differentiation processes in natural mafic magma bodies. Computers and Geosciences, 11: 53 1-546. 1988. TRACE.FOR: a program for the calculation of combined major and trace-element liquid lines of descent for natural magmatic systems. Computers and Geosciences, 14: 15-35. TATSUMI, Y., and ISHIZAKA, K. 1982. Origin of high-magnesian andesites in the Setouchi volcanic belt, southwest Japan, I. Petrological and chemical characteristics. Earth and Planetary Science Letters, 60: 293-304.