• Sulfides

In clinopyroxenite I, pyrite, pyrrhotite, and chalcopyrite are in paragenesis with interstitial and veinlet chlorite and are generally typically enclosed in it (Figure 9a–c). Occasionally, sulfide grains are localized in pyroxene but form intergrowths with chlorite (Figure 9d). In clinopyroxenite II, sulfides consisting of decomposed solid solution are localized in the interstices of clinopyroxene grains occasionally together with secondary magnetite (Figure 2b). In the contact zones of olivine and clinopyroxene grains, lattice-like chalcopyrite bornite aggregates in the marginal parts are replaced by tremolite, chlorite and serpentine (Figures 5b and 8c). In clinopyroxenite III, sulfide segregations of interstitial shapes to 2 mm in size are disseminated in the rock mass. Among sulfides, pyrite predominates quantitatively over chalcopyrite, whereas chalcopyrite, over pyrrhotite. Frequently, these sulfides form joint segregations (Figures 2c,d and 9f). Pyrrhotite segregations no more than 0.3 mm in size form intergrowths with pyrite (Figure 9d) or are enclosed in

chalcopyrite (Figure 2c). Chalcopyrite was found to contain inclusions of pentlandite and argentopentlandite Ag(Fe,Ni)8S<sup>8</sup> of 10–15 µm in size (Figure 9e, Table 9, No 16, 17).

**Figure 9.** Relationships of sulfide minerals in clinopyroxenites I (**a**–**d**) and III (**e**,**f**). (**a**) Interstitial chlorite (Chl) with inclusions of chalcopyrite (Ccp) and titanite (Ttn) in clinopyroxene (Cpx); (**b**) chlorite veinlets with amphibole rim (Amp) in clinopyroxene. Chlorite contains grains of titanite (Ttn) and partially oxidized chalcopyrite; (**c**) interstitial chlorite with inclusions of pyrrhotite (Pyh) in clinopyroxene; (**d**) intergrowth of pyrite (Py), pyrrhotite, and chlorite in clinopyroxene; (**e**) segregation of chalcopyrite in intergrowth with argentopentlandite (Apn), pentlandite (Pn), and chlorite in clinopyroxene; (**f**) interstitial segregations of pyrite and chalcopyrite in clinopyroxene. Chlorite develops along the cleavage cracks.


**Table 9.** Chemical composition of sulfides in clinopyroxenites I–III (in wt.%).

Note. spionkopite (Spi), yarrowite (Yar).

Chemical composition of sulfides of various parageneses in given in Table 9. The compositions of pyrite FeS2, chalcopyrite CuFeS2, and bornite Cu5FeS<sup>4</sup> are similar to stoichiometric composition for these sulfides. Pyrite in clinopyroxene I contains Co (up to 1 wt.%). The composition of pyrrhotite in pyrite–pyrrhotite–chalcopyrite paragenesis (clinopyroxenite I) corresponds to the formula Fe0.96–0.97S, whereas pyrrhotite–chalcopyrite– pyrite (clinopyroxenite III), to Fe0.94–0.95S. Secondary copper sulfide developed mainly on bornite in clinopyroxenite II (Figure 2b) has an intermediate composition between spionkopite (Cu39S28) and yarrowite (Cu9S8) (Table 9, No 13–15). Secondary copper sulfide contains Fe (1–1.2 wt.%).
