USING TERTIARY MIDWAY
MICROFOSSILS TO
DEERMINE THE
DEPOSITIONAL
ENVIRONMENT DURING
THE TERTIARY PERIOD
ALONG THE OUACHITA
RIVER
S
Purpose
The purpose of this experiment is to identify different microfossils in the rock layer at the
Ouachita River near Malvern in order to determine the depositional environment of the Tertiary period. Microfossils are small micro faunas that provide many information about the environment the place once they lived in. It is very useful that
Geologist use it often to age dating, show correlations, and identify the area’s environment by identifying their formations.
Hypothesis
If the Ouachita River is in the midway group during the tertiary period, which represents a marginal marine depositional environment, then the fossils should support the claim
Methodology
A bag of soil samples from the Ouachita River was obtained from the Arkansas Geological Society.
Went to Wal-Mart and purchased a bottle of 946ML Calgon.
Gathered all the necessary materials: One big bag of soils samples from Ouachita River near
Malvern around half pound, one fine paint brush, one dissecting microscope, two glass bowls, one big metal sifter, a pair of chopsticks, a small paintbrush and a slide and a dish.
Found an empty plastic water bottle, 500 mL to be exact.
A 500mL water bottle was filled with tap water and 100ML of Calgon was added.
Shaked the bottle a bit and tried to mix the Calgon with the water.
Placed the two glass bowls on the floor and poured 250ml Calgon-water mixture from the bottle to each bowls.
Putted the sifter in the bowl with the Calgon-water mixture.
Took a small amount of soil samples from the sample bag.
Poured small amount of sample soils slowly down on the sifter.
Used the chopsticks and stirred the soils with the calgon water.
Left the soils soaked in the bowl for around 2 – 3 days depended on the amount of soils, more
Methodology
Shook the sifter a bit from time to time and changed Calgon-water mixture when it got too muddy.
After two days the soil samples was soften and easier to wash.
Started washing the soils with cares and tended to wash away the muds and grasses, leaving only the fossils behind with the help of calgon water.
Washed the soils three times for each bowl, until the leftover calgon-water is clean.
Then the microfossils were appeared on the sifter.
A dissecting microscope was used for view the microfossils.
Placed all the clean microfossils in a dish and placed it under the dissecting microscope for examination.
Took all the fossils found to the geological survey.
Asked a geologist and helped to pick out more fossils from the soils.
Went to Arkansas geological survey library and found information about these fossils and what period they lived in.
Mixed 4 drops of Elmer’s washable school glue with every 6 drops of water until there were enough glue for gluing the found microfossils.
Took a small paintbrush and cutted the brush’s hairs into around 30 hairs left so the microfossils
Methodology
Used the brush and sorted the microfossils.
Started gluing the microfossils on the slide using
the glue mixture made earlier so they won’t get lost. Created a Column bar graph and recorded the
data.
Identified the fossils and what environments they
lived in.
Data/Result
Tertiary Midway Micro Fauna's Frequency
25
20
15
10
Munbers Of Micro Fauna
(Unit)
5
0
Types Of Micro Fauna
Figure 1 – shows the frequency of each Microfossil. Those
Microfossils commonly appear in the tertiary period.
Glauconite is not a fossils but an Environment control.
Data/Result
Glauconite, or sand-sized, greenish pellet that usually found in sedimentary rocks, act as an environment control, it requires four factors for its formation: “(1) Parent material (generally an expandable layer lattic silicate), (2) A source of iron and potassium
(sea water), (3) Local reducing conditions, and (4)
