Transcript Document 7152524

GEOL 3213
MICROPALEONTOLOGY
Introduction & Classification of
Conodonts
COMMON MICROFOSSILS
• Calcium phosphatic conodonts (Cambrian-Triassic)
• Major calcareous microfossils
–
–
–
–
forams
coccoliths
pteropods
ostracodes
• Major siliceous microfossils
– Radiolaria
– Diatoms
– Siliceous sponge spicules
Major Phanerozoic Planktic & Nektic Microfossil Groups
CONODONTS
• Calcium phosphatic teeth of a marine eel-like extinct
vertebrate.
The Elusive Conodont Animal
• Carboniferous
• Granton Quarry
• Scotland
Acmes of Diversity
• Late Devonian
to Carboniferous
• Ordovician
(especially
Medial
Ordovician)
Number of Genera Per Epoch
• 2 major acmes
• 4 extinctions:
–
–
–
–
End Ordovician
End Devonian
End Permian
End Triassic
Biostratigraphic Zonation
• Some conodont zones
represent only about 1
Ma, while others may be
2-3 Ma long.
• This is good for the
Paleozoic Era.
Conodont Index Fossil Genera
• Many conodont
genera have short
time ranges!
Conodont Index Fossil Genera
Conodont Colour Alteration with Heat
• Original colour = yellow
• As burial increases,
temperature increases
• Geothermal gradient = ?
• Drives volatiles (= ?)
out of organic matter in
teeth, scales, etc.
• Residue is carbon
• What is the end colour?
Conodont Colour Alteration with Heat
• Shallow burial indicated by specimens at left
• Deep burial indicated by specimens at right
CAI
• Colour Alteration Index
• Experimentally confirmed
• Geologically documented
• Code numbers recorded and
averaged for ~100
specimens in a sample.
• Plot numbers on a map or
cross section
• Contour the data
• Helps to locate source rocks
for petroleum exploration
Map of Conodont CAI Data – Contour it
CONODONTS
• 3 basic kinds of conodonts:
– Cones
– Blades & bars
– Platforms
•
•
•
•
= coniform elements
= ramiform elements
= pectiniform elements
1 to 7 kinds associated in natural assemblages
Element form genera and species
Generic names given to assemblages
Examples of ramiform conodonts
Conodont Natural Assemblage
• Carboniferous bedding surface, Illinois, USA
Examples of Assemblages
Scottognathus assemblage
Conodont Morphology and Terminology
• Morphological
terminology
for coniform,
ramiform, &
pectiniform
elements
Conodont Morphology and Terminology
• Morphological
terminology for
– Coniform elements
– Ramiform elements
– Pectiniform elements
Conodont Morphology and Terminology
Conodont Morphology and Terminology
• Muller
Conodont Morphology and Terminology
• Brasier
Conodont Morphology and Terminology
• Brasier
• Ozarkadina
• Silurian
• Palmatolepis
• Late Devonian
• Plectodina assemblage
• Coniform elements
• Ordovician
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