Geology. Козлова Е.П. - 21 стр.

      Petroleum originates by the accumulation of plant and animal remains. Many
limestone and silica deposits are also formed by plant and animal activity.
      Some uranium, vanadium, copper and other metalliferous deposits are
considered to have formed in part at least by the activity of organisms.

     2.13 Ответьте на следующие вопросы

1) How are mineral deposits classified?
2) How are magmatic deposits originated?
3) Where are pegmatites found? What do they consist of?
4) What geological processes form sedimentary deposits?
5) How can mineral deposits formed as a result of sedimentary and weathering be
grouped?
6) To what groups do the deposits of gypsum belong?
7) How are placer deposits formed?
8) Which mineral can be refered to the group of residual deposits?
9) Which minerals are formed by the activity of organisms?

     2.14 Составьте план текста 2B и перескажите его

    2.15 Прочтите и переведите текст 2C. Найдите транскрипцию
подчёркнутых слов и выучите их наизусть

                    Mineral Resources of the Orenburg Region

       The Orenburg Region is one of the few areas in Russia which is extremely rich
in natural mineral deposits such as gas, oil, combustible shales, brown coal, ferrous
and non – ferrous metals (f. ex. copper , nickel, zinc, lead). It is also worth noting the
Sol-Iletsk deposits combining 800 million tons of extremely pure rock salt.
       More than 75 minerals have been discovered in over 2 500 surveyed deposits
and almost all of them are of industrial significance. Parts of the region have yet to be
fully surveyed. Consequently, there are many minerals waiting to be explored and
discovered.
       The region has 8 desposits of brown coal, with aggregate reserves of 780
million tons. Brown coal pit mining is represented by the Tjulgan mine, which has
commercial reserves of 202,6 million tons. Orenburg region iron ores belong to rare
naturally alloyed ores with a high content of nickel and chromium. The reserves of
asphaltite are estimated at 9 million tons which contains approximately 60 000 tons
of vanadium pentoxide and 7 000 of nickel oxide. Asphaltite is found at a depth of
408-416 meters in sheets of 1-7 meters thick.
         Asbestos is one of the most important non-metallic raw mineral products. It
has a high mechanical strength, elasticity and flexibility. Asbestos is heat and alkali
resistant and has a high coefficient of fraction. Kijembay site, 400 km east of
Orenburg, is one of the world’s largest and most valuable crystallite asbestos
deposits. The main marble deposits are Aydyrlinskoye and Yasninskoye deposits.
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