The results of an integrated morphological, precision geochemistry and Raman spectroscopy study of heterogeneous and polygenic zircons from the likely paleoproterozoic mafic rocks - ore (Pt-Pd-Au) amphibolites of the Travyanaya Guba massif located in the Belomorian mobile belt, are reported. Two types of zircons differing in morphology and U, SREE and some other trace element concentrations are described. The outer parts of grains (shells or rims) and inner cores of zircons-1 and zircons-2 are characterized for the first time. Analysis of Raman spectra has shown that both highly crystalline and amorphous metamictized grains occur among high-U zircon-1 grains.
Considerable variations in spectra within one grain reflect a heterogeneous structure and varying crystallinity/amorphism of its lattice, which is associated with an irregular distribution of elements, chiefly uranium and thorium. The degree of crystallinity of the shells of zircons-1 is higher than that of the cores, which are composed of radiation-damaged zircon which emits two signals: one from the distorted crystalline lattice and the other from the zircon affected by amorphism. Low-uranium zircon-2 grains display a more homogeneous structure and a highly crystalline lattice with clear signals in the spectra. It has been shown that the integrated study of the morphology, trace element geochemistry and state of the crystalline lattice of the rims and cores of heterogeneous and poiygenic zircon grains by local methods is an efficient tool for the reconstruction of multi-stage petrological and ore-forming processes.