what is palaeontology & modes of preservation of fossils

1. FOSSIL
Mr suren N Kamble
P.G. Department of Geology
Deogiri College, Aurangabad.

2. (Palaios- Ancient, ontos-life, Logy-Study)
(Palaeontology was proposed by the de Blanville & don Waldhelm in1834)
Fossil - Remains or traces of a once-living organism.
“Fossil” (Latin prefix “Fodere” refers to digging/excavation) in its most general sense refers to
any preserved evidence of ancient biological organisms in the rock record that is obtained
through digging/extraction from the host rock.
Palaeontology…..?

3. Life assemblage
(biocenosis)
Death assemblage
(thanatocenosis)
Total fossil
assemblage
Fossils actually
discovered
Destruction of most soft tissues
Destruction of most hard tissues
Destruction of most fossils

4. Branches of Palaeontology
Palaeontology(Fossils)
Mega-Fossils
Vertebrates Invertebrates
Micro-Fossils
Foraminifers
Diatoms, Ostracods
etc.
Ichnofossils

5. Importance of Fossils
To Study the Biostratigraphy (age dating of rocks)
To Study the Evolution, Geographical Distribution of ancient animals
To Study the Paleoecology/paleoenvironmental interpretation
To Study the Paleogeography/paleobiogeography/Palaeotemperature

6. Modes of Preservation of Fossils
 Entire Body Preservation With soft parts
 Entire Skeleton Preservation Without soft parts
 Petrification & Replacement
 Mold & Cast
 Imprints
 Traces & Trails
 Burrows
Encrustation in Spelaean Environments

7. Entire Body Preservation
This is very rare mode of preservation of fossil
In this mode the entire body of the animal is
preserved with the skin in extremely dry and cold
climate
The fossil Woolly Mammoth from the Siberia
(1779) found to be entire skin and hard body part.
Amber is a natural tree resin that had hardened
through various chemical changes, sometimes this
sap surrounds an insect, preserve it with perfect
details & look like stone

8. World’s oldest baby snake found preserved in amber
 100-million-year-old baby snake preserved inside a
piece of amber from Myanmar.
 The new species—dubbed Xiaophis myanmarensis—lived
in the mid-Cretaceous period
 The fossil, which was just 5 centimeters in length

9. Entire Skeleton Preservation
This is also an rare mode of preservation of fossil
In this mode the entire Skeleton of the animal is
preserved
For preservation of this type fossils the climatic
condition should be extremely Dry or extremely Cold
A new species of South American fossil terror bird
called Llallawavis scagliai ("Scaglia's Magnificent
Bird“) more than 90% of the skeleton exquisitely
preserved (Cenozoic Age)

10. Petrification & Replacement
(The petrification is process of removal of particles of
original animal body parts and replace by the fine grain
sediments or minerals and totally convert it into stone or
hard rock)
When Organism die 'buried it tissue may be replaced by
silica calcite or pyrite or some other minerals through
water.
In short it’s the type of preservation in which alteration
of hard part by Mineral matter or Sediments
Arizona National Wood Fossil Park

11. Petrification & Replacement
fishes are petrified over limestone. The Royal Ontario
Museum

12. Mold & Cast
 When remains are buried, they are surrounded with
sediment. The impression that the buried object made in
the surrounding sediment is called an external mold.
(impression of shell exterior surface)
 If the buried object is hollow, it can also be infilled with
sediment. The impression of the interior of the buried
object is called an internal mold (also known as a
“steinkern”).(impression of shell interior surface)
 In many cases, the actual buried object (in this case a shell)
decays or is dissolved, leaving only internal and external
molds.

13. Mold & Cast
Turritela
External mould
Internal mould
Turritela

14. Imprints
These fossilized Australian Glossopteris leaves are the same ones found on
Antarctica.
These imprints basically we get in the very fine
grain sedimentary rock i.e. Shale
The leaf is sandwich between the two strata,
after the decomposition of the strata only the
replica of the glossopteris leaf remains

15. Traces & Trails
Ichnofossils

16. BURROWS
Borings are tubular burrows in firm clay and soft rock
that have been created by bivalve molluscs

17. THANK YOU