Micropaleontology

We completed operations at the first site and have been travelling the last three days to reach the main sites to be drilled on the expedition. The JR has reached record speeds of 15.9 knots due to help from the Gulf Stream and favourable winds. Yesterday we had a fabulous BBQ on deck – check out the photos on the JR’s facebook page.

In a few hours, drilling will start again and from tomorrow the micropaleontology team will be relied upon to provide rapid age determinations for each core, so the drillers know how close they are to the targeted sediments.

The photo shows the two core catcher samples examined by the micropaleontology team.  It was a good test run to see how our laboratory techniques worked and to see how fast we could get results. The nannofossil specialists just take a smear slide directly from the sample and got a result within minutes. The foram specialists had to wash their samples through a 63 micron sieve, so they took an hour or so to get a result. I trailed well behind because, before sieving the sample, I need to remove the clay by heating the sample in dilute hydrogen peroxide and then remove the calcium carbonate by adding some hydrochloric acid. Then, I sieve the sample and pipette some of the residue onto some glass slides. Finally, I set the mounting medium under ultraviolet light and place each slide under the microscope and hunt for radiolarians. I found none in the first sample and two in the next! After 4 hours of sample preparation!!

But one of the radiolarians is a useful age indicator, first appearing in the geological record about 20,000 years ago. If anyone knows of earlier records for Actinomma leptodernum please let me know!

 

Sediment samples are cleaned for radiolarian study by heating in a solution of hydrogen peroxide.

 

Sediment samples are prepared for radiolarian study by heating in a solution of hydrogen peroxide, prior to dissolving carbonate using hydrochloric acid.

 

 

 

 

 

 

 

 

 

The rest of the micropaleontology team writing their reports while the radiolarian samples bubble away in the lab. My microscope still sits quietly under its blue cover 🙁

Hiroshi, Kazu, Phil and Claudia.