Thin Section

THIN SECTION

MAX WITEK

Summary

11 polished thin sections were prepared on Exp 403. There were no large format slides requested. Almost all samples required resin impregnation. One sample was made with blue porosity dye, and two with Alizarin red stain although only one of those was successful. The other billet became substantially destroyed when immersed in the solutions. The predominant theories as to why this happened include clays swelling on contact with water in the dilute HCl solution as well as the weak acid attacking carbonate material that helped to lithify the sample. The lithologies included clays, as well as some quartz sands. Greigite and pyrite were also notable finds. These samples were analyzed under reflected light and were often subjected to further EDS analysis.

Laboratory instruments

Buehler PetroThin

The PetroThin was used extensively on Exp 403. The cut off blade as well as the grinding cup showed signs of wear, but were not replaced because the samples tended to be extremely soft. The power switch for the saw motor had failed causing the petrothin to turn itself on unattended. The switch was replaced by the ET, but since no like part was available the switch installed does not light up when activated and turns on in the opposite direction to the other switch on the front panel.

Logitech LP-50

The LP-50 was not used. Only a basic system test was performed

Logitech PM-5

The PM-5 was was not used. Only a basic system test was performed by powering on and the running the basic functions.

Logitech VS2

2 Port Vacuum System. Working properly, no issues.

Buehler MetaServ

High pitched whine observed when RPM is brought up to usual speeds. It sounds like it could be a belt rather than a bearing. Water feeds working as intended.

Hot Plate

Temperature readout is not accurate and hysteresis is very large. A temperature setting of 200-300 deg C achieves 70-100 deg c.

Freeze Dryer

No issues; working properly.

Vacuum Pumps

No issues; working properly.

Kemet Kemvac Vacuum Impregnator

No issues; working properly.

Microscope

Functional. Yellow artifact remains. Objectives slightly deviate from light path. Cause of yellow artifact was determined to be blemish on Brightfield/PPL/XPL selector mirrors. A tearing artifact that occurred in both eyepieces was observed. The cause was the Bertrand lens holder was inserted too far into the optical path. Another issue that cropped up was the power supply for the lamps would behave very inconsistently. Sometimes the transmitted or reflected or both (in sequence, not simultaneously) lights would not turn on. A known good power supply was borrowed from the microscope lab was borrowed and the issue resolved. Unfortunately no spares were available so the intermittent power supply was used for the rest of the expedition.

Laboratory procedures

Procedures from “Soft sediment thin section procedure” by Luan Heywood were used, as well as the general procedure for hard rocks.

A new method for minimizing the warping of clay sample was approved, but not used. Epoxy impregnation of unconsolidated marine sediment core subsamples for the preparation of thin sections at the Geological Survey of Canada by A. Normandeau, O. Brown, K.A. Jarrett, P. Francus, and A. De Coninck

Other laboratory issues

All remaining epoxy was solidified and disposed of properly. Other lab chemicals were processed and disposed of correctly.