Fossils
are widely dispersed just about everywhere on Earth. Almost
no fossils are encountered in some types of rock,
but large numbers are found in others. Geologists have
divided rock types into three main groups:
1. Igneous
2. Sedimentary
3. Metamorphic
The igneous category includes granite or basalt-type
rocks formed by the cooling of magma present in the depths
of the Earth, or else emitted by volcanoes in the form
of molten lava. Sedimentary rocks form when sand, silt,
mud, and other small particles or substances carried in
water are deposited on top of one another. Metamorphic
rocks are igneous or sedimentary ones that have undergone
structural changes due to high temperature and pressure
deep in the Earth.
Few
fossils are generally encountered in igneous seams.
The rare examples discovered are fossils that have resulted
when a plant or animal gets trapped inside molten lava.
Very few fossils can survive the high temperatures and pressures
that transform sedimentary strata into metamorphic rock.
Almost all fossils are found in sedimentary seams or deposits.
Nearly all sedimentary rocks are formed by substances
carried by wind or water or else from the erosion of still
other rocks. Some forms, such as coal, are made of plant
or animal remains. Clastic is the name given to sedimentary
rock formed by minute particles or grains. Sandstone and
schist are examples of such rocks. If there has been dissolution
in the substances transported, then due either to chemical
solution or vaporization, "organic" sedimentary
beds form. Examples of such rocks are limestone and dolomite.
In general, sedimentary rock seams are a mixture of clastic
and organic seams. Fossils are usually seen in shales,
schists, sandstone and limestone formed from calcium carbonate. This article is based on the works of Harun
Yahya
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INTRODUCTION
 Some
150 years ago, the British naturalist Charles Darwin
proposed a theory based on various observations
made during his travels, but which could not be
supported by any subsequent scientific findings.
In essence, his theory of evolution consisted of
various scenarios, ... MoreWHAT IS A FOSSIL?
 In
the broadest definition, a fossil is the remains
of a living thing that lived long ago and that has
survived down to the present day by being preserved
under natural conditions. The fossils that come
down to us are parts of an organism, or remains
left behind when the living thing concerned was
still alive ... More |
Fossil Specimens Discovered in The USA