The early geological investigations on the territory of Primorskii Krai (then  a part of Ussuriiskii Krai) began in the middle of the XIX century. They were carried out by Russian Geographical Society of Russian Academy of Sciences in connection with the study of gold  and prospecting along the Trans-Siberian railway. The  Department of Mines lead by D.L.Ivanov  did these works. One of the workers of this department was A.N. Krishtofovich. He gathered large paleontological collections, studied the remains of Mesozoic flora, summarized the materials on the stratigraphy of Ussuriiskii Krai, and compared them with those on stratigraphy of Korea and Manchuria. These investigations, predominantly geographic, on key intersections, gave the most extensive information on geological structure of the region. Also, prospects for useful minerals, were outlined.
      In 1922 in Vladivostok, the Geological Committee and then  Far East Branch were organized for the study of  the geology and development of its mineral resources. They did geological surveys of coal basins and gold districts in the  southern part of the region. E.E. Anert summarized the results of these works in several articles and  a monograph named   Mineral wealth of the Far East (1928). In 1923 together with A.N. Krishtofovich, E.E. Anert wrote  Geological essay of Primorye.
      In 1924,  exploration began in Olga-Tetyukhe district. In the Sidatun River basin, cassiterite  was found..
      Industrialization of the USSR, that began in 1929, needed a reliable mineral source and required reorganization of the geological service. In the Far East,  the Far East  Geological-Prospecting Trust (DVGRT)  was formed and later reformed into the Far East Geological Administration (DVGU). These organizations developed middle-scale geological survey in the industrial districts. Subject investigations on stratigraphy and paleontology were carried out by the All-Union Geological Institute in Leningrad (TsNIGRI). A.N. Krishtofovich continued studying  plant fossils.New names appeared in Primorye : V.D. Prinada, L.D. Kiparisova, and V.I. Bodylevsky, who became well-known later.
      In 1932, A.N. Krishtofovichs monograph Geological review of the  countries of the Far East was published. It contained  material all of the  Far East, including foreign countries. The study of intrusive rocks at that time was done by P.S. Bretshtein, S.P. Solovyev, and M.A. Favorskaya.
     In  1935, the Far East Branch of the USSR Academy of Sciences was founded with a geological department. G.P.Volarovich and V.Z. Skorokhod, in this department, compiled the first small-scale geological map of Primorskii Krai with an explanation.  Geologists of the Far East Geological Administration (DVGU) A.Z. Lazarev, G.P. Volarovich, S.F.Usenko, and others, discovered large tin deposits in Fudzin and Tadushi river basins. By 1939, V.S. Bulygo had explored new polymetallic and brown coal deposits in Dalnegorsk  district. In 1941, V.Z. Skorokhod, in the monograph Main features of geological  structure of the southern part of the Soviet Far East, summarized  materials on geology and useful minerals of this region.
      Geological works carried out before  the Second World War, resulted in the discovery of new districts with tin and tin-polymetallic mineralization and identified the reserves of hard  and brown coals, building materials, and underground water in the region. During  War , at the known mines  and coal deposits and geological prospecting was carried out. They were lead by V.N. Vereshchagin,  N.P. Zabolotnaya, D.I. Ivliev, N.V. Kolbov, M.P. Materikov, V.V. Medvedev, S.A.Muzylev, E.S.Pavlov. A.I.Savchenko, K.A.Sorokin, and others. Later, many of them became famous geologists and leaders of geological service in Primorye.
    After war ,  stratigraphy of sedimentary and volcanogenic units were studied and the main epochs of tectogenesis, magmatism, and ore formation were distinguished, and new deposits of polymetals, building  materials, coal, and mineral resources were explored. In particular, under the leadership  of M.P. Materikov, theVoznesenka ore district was discovered, and the geologists of DVGU compiled a small-scale geological map of the South Far East with an explanation. However, on  geological-survey prospecting maps of the region, white spots remained. The geological surveys of middle and large scales, as well as investigations on stratigraphy, tectonics,  magmatism, and metallogeny, were insufficient. A powerful incentive to the geological study of Primorskii Krai was the organization  in Vladivostok of Primorsky Geological Administration (PGU), that combined all kinds of geological-survey and prospecting works. One of the main services  of PGU was that by 1955, nearly the total territory of Primorye was covered by the middle-scale geological surveys, and prospecting showed a large belt of tin mineralization from Kavalerovo ore district to the basins of Iman (Bolshaya Ussurka), Armu, and Bikin rivers, and as done by the leadership of M.P. Materikov, P.N. Antonov,, N.I. Lavrik, and others,  the Armu-Iman ore district was discovered with tin, polymetals, and rare elements. The early large-scale geological surveys in 1947 in the Lifudzin ore district (A.F. Baranov, V.I. Sinyakov), in 1949 in Tetyukhe and Kavalerovo districts (R.G. Ostroumov, A.D. Kolchina, L.A. Nevolin, and others), and in 1954    in Notto River head (V.I. Silantyev), in Kirovsky district (A.I. Burde and E.V. Zharov), and in Spassky, Chernigovsky, and Ussuriisky (Yu.N. Oleinik) districts .
      Stratigraphic, paleontological, lithological, petrological, ore-metallogenic, and other investigations were carried out  by the All-Union Research Geological Institute (VSEGEI), Geological Institute of the USSR Academy of Sciences, Moscow (GIN), and Far East Department of Siberian Branch of the USSR Academy of Sciences (DVF SO AN). In early 1950s there was a regional-geological section, that in 1958, thanks to  the initiative of E.A.Radkevich, I.N.Govorov, and others, was reformed into the Geological Institute ( now Far East Geological Institute of the Far Eastern Branch of the Russian Academy of Sciences). Geologists of the All- Union Institute of the USSR (IGN) and the Institute Gipronickel also studied ore deposits for long time. Geomorphological investigations were carried out by the Institute of Geography of the USSR Academy of Sciences (GIN). Hydrogeological surveys were done by the Fourth  Geological Administration, and by 1957,  the whole territory of the region was covered with the exception of the north-western mountains.
During this period, large theoretical general studies were done. In 1950,  a tectonic study was compiled by the geologists of VSEGEI on the basis of major structural-facial zones. Since 1953 more detailed schemes by M.I. Itsikson, P.N. Kropotkin, S.A. Salun, N.A. Belyavsky, Yu.A. Gromov, and M.G. Organov appeared. In these studies, the main units of Sikhote-Alin were shown: Khanka massif, Daubikhe zone, the Main anticlinorium and Main synclinorium,  and Coastal anticlinal zone. These main structures are part of the later tectonic studies, , though under different names and different genetic interpretations. The most important work  - Geology of Primorskii Krai -   was prepared under the leadership of N.A.Belyavsky   and published in1956 with geological map and tectonic analysis.. This monograph summarized  all the geological investigations in Primorye,  in more than 300 pages. For the next decade, it was a manual  for Primorye geologists.
      The peak of geological investigations in Primorye was the period between  the late 1950s and early 1980s. In this period, many new and interesting materials and ideas appeared, that allowed  the geology of Primorye to be interpreted in  new ways. By this period, PGU, the expedition of the Fourth Geological Administration,  and the Geological Institute of DVF SO AN were replenished by many specialists in different fields, including geological surveying and prospecting, with graduating students from the Far East Polytechnical Institute (Vladivostok) and other places (Moscow, Leningrad, Blagoveshchensk, Kishinev, Saratov, Lvov, etc.). It was possible to begin and develop very laborious but extremely  important works for compiling  middle-scale geological maps and prospecting works. Large-scale surveys were also done, and in ore districts, detailed geological surveys were done. The works were carried out by the large  expeditions of PGU: South-Primorye  central geological survey expedition  (Uglovoe settlement) and geological prospecting expeditions (Armu-Iman, Olga-Tetyukhe, Kavalerovo, Voznesenka).
      The newly-formed laboratories and parties of the Subject Expedition of PGU studied a huge amount of  field material that was  continuously coming from numerous seasonal and year-round field parties working in all districts of Primorye. The workers of the  Expedition carried out paleontological, palinological, stratigraphic investigations, and determinations of absolute age.
      This geological activity in Primorye was favoured in large part  by the fact that  highly skilled experienced gelogists lead  parties, expeditions, and administration: I.I. Bersenev,  B.A. Ivanov, N.I. Lavrik, M.P. Materikov, R.E. Ostroumov. In the Geological Department of DVF SO AN such specialists  were E.A.Radkevich, I.N.Govorov, M.G.Organov, N.P.Vasilkovsky, A.M.Smirnov, and others.
      The types of products was strengthened  and widened. Since 1956, an important annual meeting was the  Interdepartmental  stratigraphic meetings on unification of the stratigraphic schemes of the Far East, held in Khabarovsk with participation of geologists of the Far East and the central scientific institutes. Four meetings were held that were very important for working out a single approach to the compiling of the legends for geological maps  of 1:200 000 scale of Sikhote-Alin series.
      A new scheme of tectonic areas of Primorye was worked out by I.I. Bersenev in 1959-1969. He distinguished four areas of folding: Khanka  (Caledonian (Baikal),  Grodekovo and South-Primorskaya  (Hercinian and  Mesozoic), and Sikhote-Alin  (Mesozoic). He distinguished also the South-Sikhote-Alin latitudinal suture that bordered the Khanka massif to the south.
      In 1969, as a result of the work of many geologists, and due to a great organizing role of a chief geologist of PGU,  I.I. Bersenev, a fundamental work Geology of the USSR, volume XXXII, Primorskii Krai was published  in two parts. It was edited by I.I. Bersenev and accompanied by a geological map, and  a map of useful minerals of Primorye at 1:1000 000 scale with a tectonic analysis. The volume included much factual material and important general conclusions on the geological  structure, geological history of Primorye,  and useful minerals.
     Untill now it was a unique   generalization on geology and useful minerals of Primorye, although, , many ideas,  especially on genesis of materials are old.
     From 1950 prospecting of tin  and polymetal deposits, geophysical studies were carried out. Methods of large-scale and detailed geophysical works at deposts were gradually worked out, and helped to identify prospects of  known and the discovery of new deposits. In 1957, small-  and middle-scale geophysical surveys,  including profile seismic studies began, and resulted in a valuable contribution to the knowledge of deep structure of Primorye.
     In the  Pavlovsky coal deposit,  open-pit  mining of coal deposits  started and continued in Bikin and other quarries. Discovery and exploitation of Tetyukhe datolite boron  deposit resulted in the construction of a powerful chemical enterprise that produced varnish-paint articles, cleansing agents, etc. In the early 1960s,  structural profile drilling discovered deep-seated ore bodies with big ore reserves that inhaled a new life in Tetyukhe (Dalnegorsk)  mining and processing enterprise.
     By the end of the 1980s, many-years of arduous work by geologists  made Primorskii Krai one of the best studied regions of the Russian Far East. The region played an important role in providing the Soviet Union with mineral raw materials, and a large metallurgical industry.
     During the recent ten years of  perestroika especially after the USSR dissolution, the geological service of Primorye fell into decay because of the lack financing. The Primorsky Geological Administration (PGU) was reformed into Primorsky Geological Committee (Geolkom). The numbers of specialists sharply reduced. Now many highly skilled specialists  of the former Ministry of Geology work in industrial organizations that are parts of various companies with different  names, where  geology plays secondary role. Work on geological surveys  and mapping has  practically stopped. The last small-scale geological maps of Primorskii Krai were compiled more than 10 years ago and published  as non-colored maps. Exploitation of  known deposits is often unprofitable, as the cost price of mining and processing of mineral products is higher than the price of imports.
     Much better is the situation  in the Institutes of the Russian Academy of Sciences that deal with Primorye, and in particular in the Far East Geological Institute. Our Institute carries out field and laboratory investigations, thanks mainly to the financial support from Russian and International grants. The Far East Geological Institute continues tectonic, paleontological-stratigraphic, sedimentological, mineralogical, geochemical, petrological ore-metallogenic, regional geological, and other investigations. However, perestroika has caused corrections here also: geography work is sharply narrowed, marine and shelf researches are stopped, the level of analytical works is reduced mainly because there is no possibility to buy modern instruments.
    (information till 1969 is taken from  the XXXII Volume of Geology of the USSR)

 Pavel MARKEVICH, doctor of geological and mineralogical sciences, chief, Laboratory of sedimentology, Far East Geological Institute, Far Eastern Branch, Russian Academy of Sciences