biostratigraphy and paleoecology of cretaceous/tertiary boundary in ...

Chapter one
Introduction
2- Hydrogen peroxide method: Another preparation method was introduced in
this research is hydrogen peroxide oxidation method,( H 2 O 2 ) , oxidizes organic
mater and producing (CO 2 ) pressure in the pore spaces proved to be winning
and it is the most favored method to separate foraminiferal test from the rock
type of soft, friable, porous and permeable rocks. The method used H 2 O 2
(concentration of 20 - 30% ) and water with duration time between 2 – 3
hours.
3-The third method is more classical and traditional preparation for extraction
foraminifera from the rock matrix, in which the particles were boiled in water
for 3 – 5 hours with addition of few grams of Sodium hydroxide ( Na OH) or
Sodium carbonate (Na 2 CO 3) which produces CO 2 as well as crystals of salt
within the pore spaces.
-The disaggregated samples were washed under tap water through a 63-µm
sieve until clean foraminiferal residues were recovered. Then to remove the
residual encrustations and clay materials the residue is dipped again in beaker
with water diluted desogen and placed into an ultrasonic vibrator for half hour.
The use of ultrasonic cleaner proved to be successful in mechanical cleaning
of individual specimens without breaking them. The final washed residue was
dried in an oven at 50 C o or by using the sand bath, Planktonic and benthonic
foraminifera are well preserved in the Smaquli area for both Upper Cretaceous
and Lower Tertiary (Danian) forams, but in other sections the preservation is
moderate, although original calcite shells are recrystallized in some samples
of Sirwan section.
For each sample about 200—300 specimen were picked from
representative sample split. Population counts for each sample are based on
random split, of specimens from 63 µm and 150 µm fraction respectively.
Planktonic and benthonic foraminifera were picked from each sample and
mounted. The remaining samples were used to searching for rare species.
A- Laboratory analysis and scanning electron microscope photography
were processed in the Institute for Paleontology, University of Bonn, Germany.
21