Geologically speaking, the Maramures Mountains are classified in three structural areas:

  • The crystalline-Mesozoic area, which contains the crystalline massif and the permo-Mesozoic coat;
  • The flysch area, externally to the Maramures crystalline massif, which mostly contains Cretaceous formations belonging to the internal Oriental Carpathian flysch that are folded and corrugated in the Austrian phase;
  • The trans-Carpathian or Pannonic Maramures area corresponding to the Maramures depression. Most of the series deposited on the geosyncline axis have overthrust terms bordering the south-western flank of the Maramures crystalline massif, which form two creeks with Paleocene-Neocene deposits: Ruscova and Borsa.

      The crystalline-Mesozoic area 

      The oldest term of the geological formations is represented by crystalline schists covering most of the Maramures Mountains. Looking like a large, unitary crest, it is an extension of the central - Carpathian unit striking NW - SE, from which the crystalline wall of Vaser stands out toward SW and is situated between the sedimentary basins of Ruscova and Borsa. 
      Three series can be pointed out in this area: 

  • The upper mezometamorphic pre-Proterozoic series, the Bretila series, is spread in the lower Vaser basin and in the north on Ruscova Valley at Poienile de sub Munte and in the upper basins of the Bistra and Frumu?eaua Valleys, from where it goes all the way up to Pop Ivan Peak. This series is represented by mica-schists, augen gneiss, sericite schists, amphibolite, pegmatite.
  • The epimetamorphic Upper Proterozoic - Lower Paleozoic series is wide spread in the upper basin of ?ib?u, in the Vaser and ?âsla basins and in the north in the Poienile de sub Munte region. The series is formed of complex tengen on top of which there is a volcanogene complex.
  • The epimetamorphic Paleozoic series situated in the Devonian - Carboniferous. It occurs in the basin of Vaser Valley on a small area on the middle course of Pe?tilor Valley (north of Vi?eul de Sus) and west of Pop Ivan on the Bistra Valley. The series is formed of phyllite, chlorite slate and crystalline limestone.

      The sedimentary coat of the crystalline - Mesozoic is formed of Permian, Triassic and Jurassic; it is developed on a restricted area as synclines caught between the crystalline and nappe outliers or as olistolite blocks in the flysch. The Cretaceous formations are only met in the north, are more developed and have been deposited after the Austrian folding. 

      The flysch area 

      The flysch is situated in the northeast on the outer side of the Maramures crystalline massif. The oldest rocks belong to the Lower and Medium Triassic and are formed of quartz sandstone, clay schists violaceous at the bottom and partly - dolomite limestone. 
      The Medium Jurassic is formed of quartz conglomerates, black micaceous sandstone, limestone in plates with coaly faces, clay schists with strongly tectonised basic pyroclastite breaks. By comparison with the Hungarian succession of the same unit (the Kameny - Potok series) one may assume that it belongs to the Medium Jurassic. 
      The most spread formation of the Upper Jurassic - Lower Cretaceous is represented by the black flysch comprised of argillite, sandy schists, grey sandstone, limy breccia and calcarenite and is intercalated by basic eruptive rocks - balsalt tuffs and basalt. The black flysch occurs in the upper basin of Ruscovei, north of Poienile de sub Munte, in the mountainous group Farc?u-Mihailecu and northeast of this group, then in the upper basin of Vaser toward the eastern border. 

      The trans-Carpathian or Pannonic Maramures area 

      The formations of the trans-Carpathian area lie on all the southwestern side of the Maramures crystalline massif; it is the most developed in the Ruscova and Borsa Creeks. The deposits belong to the Paleocene, Eocene, Oligocene and Lower Miocene. 

      The mineral wealth is comprised of polymetallic sulphides at Novicior, M?gura Cataramei, Toroioaga and Burloaia. At the bottom of the volcanic mountains there are mineral springs used locally, and nowadays for commercial purposes.