Index Fossils and Formation of Fossils REPORT

INDEX FOSSIL and FORMATION of FOSSILS REPORT

1. Lesson 3: index
fossils and
formation of fossils

2. Identify four ways in which
organisms can be preserved as
fossils
Describe index fossils and how it can
be used to know the age of rock
List examples of fossilized traces of
organisms
Learning targets:

3. Is used to establish the age of rock layers.
Fossils act as "bookmarks" in the stratified rock layers so
that geologists can easily determine the age or period of
the rock layers, it can be used as an indicator for the age
of the rock.
Fossils of organisms that drifted in the upper layers of the
ocean are particularly useful as index fossils. But they
may be distributed all over the world.
index fossil

4. Abundance
Widespread Distribution
Distinct Identifiable Features
Existed only for a short yet
specific span of Geologic Time
fOUR CHARACTERISTICS FOR A
FOSSIL TO BE CONSIDERED AN
INDEX FOSSIL

5. Ammonites
Trilobites
Graptolites
are often used as index fossil
Many fossils may qualify as index fossil.

6. In marine layers, a commonly used index fossil is the
single-celled Protista.
Viviparus glacialis, a mollusk, serves as an index fossil for
the Pleistocene.
index fossil

7. Mummification
amber
tar
seeps
petrification
freezing
how
Fossils
form

8. Mummified remains are often in very
dry places where bacteria that cause
decay cannot survive.
The Egyptian mummy is a very good
example.
The Body’s Internal Organs are
extracted, the body is treated, then
wrapped in carefully prepared strips of
cloth.
mummification

9. amber
Amber is hardened tree sap.
Insect become trapped in sticky
sap and are preserved when the
sap hardens.
Delicate parts like legs, wings, and
antennae are preserved.
In very rare cases, DNA has been
recovered from amber.

10. When thick petroleum oozes to
Earth’s surface, the petroleum
forms a tar seep.
Tar seeps are commonly covered
by water.
The remains of the animals are
covered by Tar and preserved.
tar seeps

11. The low temperatures of
frozen soil and ice can
protect and preserve
organisms.
Organisms that were
buried in frozen soil or ice
do not Decay.
freezing

12. petrification
Organic matter exposed to
minerals over a long period is
turned into a stony material.
The mineral solutions in
groundwater replace the
organic materials of the
organism.

13. The types of fossils, aside from the
preservation of the organisms,
includes:
Imprints
Molds and Casts
Coprolites
Gastroliths
types of fossils

14. imprints
Imprints are carbonized imprints of
leaves, stems, flowers, and even fish that
are made in soft mud or clay.
These are found preserved in
sedimentary rocks.
A carbon-rich film is left behind when the
original organic material partially
decays.
Imprints show surface features of the
organism.

15. Molds and Casts are three-
dimentional impressions in which
the surface contours of an
organism are preserved.
While mold is simply the hardened
impression of the organism, the
cast is a replica of the original
organism formed from the mold.
Molds and casts

16. Fossilized dung or waste
materials from ancient
animals are called
coprolites.
This type of fossil reveals
the feeding habits of
ancient animals.
coprolites

17. gastroliths
a stone or pebble ingested by an
animal and functioning to grind
food in gastric digestion.
Also known as gut or gizzard
stones, gastroliths are common
digestive aids among
amphibians, reptiles, birds, and
dinosaurs. their primary function
is to help grind food matter.

18. Thank you
very much