PLACER OF IRON-BEARING MINERALS IN THE SAKHALIN REGION

Abstract

Yuriy A. Bilibin has repeatedly stressed that in order to understand the picture of the formation of placers, you need to know the full cycle of their transformations. Much attention has been paid in recent years to the problems of finding ancient buried placers and placers complex structure. The rich reserves of minerals in placers are explained by the multiplicity of their genetic types, which allow involving new deposits in commercial exploitation. The relevance of the work is caused by the need to identify new sources of iron, titanium and vanadium in terms of reducing the resources of the mineral resource base. Exploration works performed to identify placers, the most promising for development, can be carried out on the basis of the awareness of the genesis of their formation. The main aim of the research is to study the laws of distribution patterns of placers of ferrous minerals within the Sakhalin region, identify the petrogenetic features of the prevailing minerals, define the prospects of exploration of deposits of iron-containing raw materials, assess the economic expediency of their extraction. The methods. We have researched iron-titanium-oxide minerals from different silicic-acidic rocks of island-arc volcanogenic complexes of Great Kuril String of islands. Thin sections of samples of rock and magnetic fraction of crushed samples were prepared. The thin sections of the rocks were studied under a polarizing microscope. Crushed samples of rocks and their monomineral fractions were studied by means of chemical analytical methods (gravimetric, titrometric, spectrophotometric, X-ray fluorescence, mass spectrometry with inductively coupled plasma). The results. We have completed studies of the patterns of formation of ferruginous placers and identified their main types. There are two types of placers with different conditions of alimentation zone of minerals on the coasts of the Russian Far East. One of them – Kuril-Kamchatka province of placers actually titanomagnetite – is located on the territory of the Sakhalin region. The beach placers and dune deposits of low terraces dominate on the Islands of the Kuril Arc. The tufo-sandstone, pumice, and pumice-scoria pyroclastic deposits play the main role in delivering the minerals in placers of this type. Crystals of iron-containing minerals in rocks of volcanogenic complexes have rather different sizes: from small, dusty to large well-expressed crystals, more than 1–2 mm in size. The chemical composition of titanomagnetites of different volcanic complexes varies depending on silica acidity of rocks. Productive rocks are characterized by high content of iron, titanium and vanadium. Coastal-marine, as well as ancient buried placers contain significant amounts of iron-containing minerals. Studying of technological schemes of processing of iron-containing mineral raw materials showed that some of them would allow carrying out their processing with receiving the highly sought final products. Under certain economic conditions, the development of placers may be appropriate.

Keywords

• metalic natural resources
• placers of titanomagnetite
• continental margin
• sakhalin region
• petrogenesis
• ferrous minerals
• titanium
• vanadium
• accessory elements-impurities
• economic efficiency