The Hitachi TM300 microscope is proving to be a powerful tool at the British Antarctic Survey laboratories.
With minimum specimen preparation needed, the Hitachi TM300 microscope is helping marine biologists to categorise newly discovered species from Antarctica.
In addition, the elemental analysis capabilities of the instrument are enabling geologists to better understand geological evolution in the region. The compact size of the instrument means that it even has the potential to be taken on exploration missions.
A large and diverse number of marine species are found in the Antarctic region, and every new species discovered needs to be properly described.
The extensive magnification range and high depth of field provided by the TM3000 allows morphological details of shells and gills, for example, on species such as gastropods, bivalves and many others to be viewed, measured and recorded.
The microscope is also used to compare fauna currently existing in the region with previously discovered examples.
Cores from marine sediment retrieved from the region contain diatoms that can be thousands of years old. Comparisons with current examples can reveal possible differences in climate over the period. Shorter term comparisons can be made with archived fauna collected since the earliest sample collecting expeditions in the 1940s.
The formation and subsequent geological evolution of Antarctica remain uncertain since it is almost entirely covered in ice.
However, by investigating the chemical and isotopic composition of resistant mineral grains such as feldspars, which have been eroded and transported from the deep interior by ice, or by rivers prior to the growth of the East Antarctic ice sheet, the hidden rock age and environment of formation can be revealed.
Low magnification backscattered images from polished samples in the TM3000 can distinguish the feldspars from the more abundant mineral quartz by virtue of their slightly higher mean atomic number.
The Quantax70 EDS system is then used to obtain some basic compositional and textural information.
The composition and how intergrowths of different feldspar types occur (texture) is partly controlled by the processes which formed them.
The compositional information obtained in this way can then be married with Pb isotope data obtained using laser ablation MC-ICP-MS to provide a more comprehensive idea of the sub-glacial geology than would be obtained from the isotope data alone.
