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To whom ever this may concern, I have a few questions regarding geology: 1)I am curious as to know what types of rocks are metals found in? 2)What plant or animal MATERIALS are likely to form fossils? 3)The majority of rocks are composed of what types of minerals? Thank you for taking your time to answer these questions.
Question Date: 2007-03-25
Answer 1:

1. Metals are found in silicate and oxide minerals generally speaking. A few important metals are found in their native state. Gold is one such example. Gold is usually found in igneous or metamorphic rocks although important Placer deposits are found in sedimentary rocks. These questions can be easily answered by picking up an elementary physical geology book. Also there are many simple mineralogy books. If you read these books you will have all the answers.

2. Anything can be fossilized although bones and shells are most easily preserved.

The most common mineral in the crust are quartz z and feldspars the most common mineral in the upper 400 km of mantle 9below the crust) is olivine. The most common mineral in the lower mantle is perovskite.

Answer 2:

There are a number of patterns regarding which plants and animals are most likely to fossilize:

1. Hard parts - plants and animals with more durable "body" parts are more likely to fossilize.So, we don't have a good fossil record for the evolution of animals like jellyfish, but we know tons about clams.

2. Where they lived. The environment that an organism lived in also determines whether or not it is likely to fossilize. Fossils tend to form in places where there is water that carries a lot of sediment that can quickly bury a plant or animal. So, a cactus is unlikely to have a good fossil record, but fish have great fossil records.

3. When they lived. Organisms that lived 300 million years ago are less likely to be found in the fossil record than those that lived 5 million years ago, just because it's less likely that they get destroyed by things like volcanoes, faults, erosion, etc.

The majority of rocks are composed of what types of minerals?

The most common mineral in the Earth's crust is quartz (SiO2), but feldspars, micas, calcite, and olivine are also very abundant.

Answer 3:

Metal ions are found in most rocks. The vast majority of minerals are basically salts between a positively-charged cation, usually a metal, and an anion. As for where ores are found, metal concentrations that are available for extraction, those usually happen in metamorphic rocks, particularly those altered by hot metal-rich hydrothermal waters.

Shells, which are already mineral, are among the best, but wood, cellulose, and sometimes bone (also mineral) tend to have fairly high "preservation potential" as well.

Well, excluding deeply-buried metamorphic rocks, the most common familiar minerals are:

  • Quartz (silicon dioxide)
  • Orthoclase (potassium aluminum silicate)
  • Albite (sodium aluminum silicate)
  • Anorthite (calcium aluminum silicate)
  • Micas (silicates containing iron and magnesium)
  • Amphibole (like micas, but more iron and magnesium)
  • Pyroxene (yet more iron and magnesium)
  • Olivine (the most iron and magnesium-rich common rocks)
  • Calcite (calcium carbonate)
  • Aragonite (calcium carbonate, an isomer of calcite)
  • Dolomite (calcium magnesium carbonate)
  • Gypsum (calcium sulphate)
  • Halite (table salt - sodium chloride)
  • Kaolinite (a clay; contains aluminum)
  • Bentonite (more clay)
  • Zeolite (yet another type of clay)
  • Garnet (not sure, got some exotic stuff, a metamorphicmineral)
  • Epidote (see as for garnet)
  • Chlorite (basically a metamorphic mica)
  • Ice (hydrogen oxide, better known as water

Answer 4:

1) That's a great question with a not so simple answer. A lot of nickel and iron are found in meteorites, and a lot of metals are found in hydrothermal vent systems, such as near a spreading center on the ocean floor or at Yellowstone. Most rocks have metals in them, so to really answer your question, I'd need to know what type of metals you're looking for. Your best bet, however, is from hydrothermal alteration--so think really hot, metal rich water that smells really bad.

2) The parts of animals and plants that form fossils are the hard parts, like shells and bones. Usually these parts are made of calcium carbonate. Soft tissue is rarely preserved, which is why most fossils don't have preserved organs or muscle.

3) The majority of rocks on the surface of the Earth are made of plagioclase and quartz plus a lot of other minerals. Most of the rocks in the mantle are made of olivine. The core of the Earth is almost 100% iron and nickel.

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