The ideal slide contains particle sizes ranging between 0 and 30µm with an even spatial distribution throughout the slide. The gap between individual particles should be sufficient for nannofossils to be easily located and identified.
The particle size variation must be constant between nannologist but can be modified according to the age of sediments. The size variation may be controlled by the time allowed to settle from suspension before pipetting the sample. The spatial distribution of particles may vary between nannologist and can be influenced by the quantity of distilled water used to process the sample.
Place a small piece of the sample onto a glass slide. Add one or two drops of distilled water onto the sample to make a mixture.
Smear the mixture evenly and thinly on the surface of the glass slide
Dry the slide on a hot plate
Scrap the dried mixture onto a separate glass slide
Stir scrapped dried mixture with immersion oil (viscosity, cSt¼21,000)
Place the coverslip on the mixture
Wait about 3-4 hours (until mixture settles between the glass slide and the coverslip) before examining to slide
To examine the slide, use a sharp object such as "a foram picking needle" to poke the coverslip to disturb the mixture gently
Clearly label the microscope slide.
Place a small piece of the sample which is a good representative of the sedimentary rock, onto a glass slide. Add one or two drops of distilled water onto the sample.
Crush it on the slide with a glass rod to make a thick suspension (clean the rod in diluted hydrochloric acid after each sample preparation).
Using a paintbrush or toothpick, smear the suspension evenly and thinly on the surface of the slide (clean the brush in diluted hydrochloric acid after each sample preparation and use a new toothpick for each sample).
Dry the slide on a hot plate.
Affix the coverslip using an optical mounting medium (Norland Optical Adhesive 61).
Wrap the small but representative sample in a paper towel.
Crush it gently using a small hammer, place the crushed sediment into a beaker, and add distilled water.
Crush it gently using a small hammer, place the crushed sediment into a beaker, and add distilled water. The soaking time is a matter of choice and can be varied between 1 and 12 hours. Because nannofossils are prone to etching, dissolution or overgrowth, we can avoid the soaking procedure of the sample. Stir and leave to disintegrate as required (we can be substitute by keeping the sample soaking time to a minimum or avoiding this step altogether).
Thinly spray the suspension onto the labelled glass slide using a disposable pipette.
Dry the slide on a hot plate.
Affix the coverslip using an optical mounting medium (Norland Optical Adhesive 61.)
Wrap the small but representative sample in a paper towel.
Crush it gently using a small hammer.
Place the crushed sediment into a beaker and add distilled water. Soak it for 12 hours.
Decant the suspension into a labelled test tube and place it into a centrifuge.
Stop the centrifuge immediately after spinning it at 350 rpm for 30 seconds (this procedure discards the particles above 30micron).
Decant supernatant into another labelled test tube and add distilled water.
Spin the decanted supernatant at 850 rpm for 1 minute.
Discard supernatant containing particles less than 2 microns.
Re-suspend the settled sediments using distilled water and repeat the process immediately as above until the supernatant is clear.
Dilute the settled sediments, then spray them onto a slide.
Dry the slide on a hot plate.
Affix the coverslip using an optical mounting medium (Norland Optical Adhesive 61.)
Wrap the small but representative sample in a paper towel and crush it gently using a small hammer.
Place the crushed sediment into a beaker and add distilled water.
Stir the suspension and wait 1 or 2 minutes for the sediment to settle. Discard the settled fraction.
Place the supernatant into another beaker.
Allow the suspended sediment to settle for 10 to 15 minutes.
Discard the supernatant and use the settled fraction.
Dilute the settled sediments then spray onto a slide.
Dry the slide on a hot plate.
Affix the coverslip using an optical mounting medium (Norland Optical Adhesive 61.)