In the rock cuttings from the main hole, CCSD, Na- and Zn bearing spinel occurred as exsolution lamella in ilmenite and magnetite. The mineral is about 5 similar to 60 mu m in width and 2 similar to 3 mu m in length, composed of MgO 17. 143 similar to 22. 337wt%, Al(2)O(3)63. 646 similar to 66. 492wt%, FeO 9.784 similar to 13. 924wt%, ZnO 1. 649 similar to 6.386wt%, Na2O 0. 029 similar to 0. 219wt%, where Na2O and ZnO are positively in different grains. By x-ray analysis of synchrotron light source, the spinel is cubic symmetry with space group of Fm3m and crystal cell parameter of a =0. 83781nm. With the fact that the spinel is associated with ilmenite, magnetite, garnet (pyr = 50 similar to 58mol%) and the garnet is retrograded into orthopyroxene and Mg-chlorite, the spinel should be derived from ultramafic, and experienced amphibolite facies metamorphism. The phenomenon of miscibility gap and exsolution texture are widely occurred in the oxide minerals between Mt-Usp, Mt-Sp1 and Mt-Ilm. According to the known petrologic experiments of Mt-Usp binary system and Ilm-Gk-Hem ternary system, the oxygen fugacity of the rocks in the main hole is low and forming temperature is at least over 720 degrees C. The ferro-titanium oxides exsoluted during ultramafic magma crystallization, but later in ultrahigh pressure metamorphism may be formed solid solutions and exsoluted again after temperature decrease.
