Department 230 – Rock geochemistry

Section 232 – Section of special methods

In this section, a number of special methods is used.

In the laboratory, a variety of different types of material are prepared for the microscopic examination. This includes natural minerals and rocks as well as artificial solid materials that may be coherent or friable, permeable or impermeable. Thin sections, polished blocks and polished sections, grain mounts and double-sided polished wafers are prepared for examination using a range of analytical equipment. This includes routine petrological and mineralogical investigation in transmitted and reflected light carried out using optical microscopes, as well as SEM and electron probe microanalysis and cathodoluminescence.

In the mineral separation laboratory, depending on the physical and chemical properties of the material, separates of individual minerals from rocks are made for further analyses. The individual minerals are separated using magnetic, gravitational, morphological, flotation and partial dissolution techniques.

In the optical microscopy laboratory, mineral and rock samples can be studied using a binocular and polarization microscope, in the transmitted and reflected light. Photo-documentation and object measurements can be taken. The heavy minerals suites in rock samples are also studied.

Section 233 – Section of mineralogy

Section of mineralogy covers several laboratories which actively collaborate on research activities within the field of mineralogy.

The Laboratory of electron microscopy and microanalysis is chiefly concerned with the development and application of microscopic methods for geological materials studies.

The Laboratory of experimental mineralogy is predominantly focused on synthesis of chalcogenides and PGE phases, study of phase relations, and description of new phases and minerals.

The laboratory of fluid inclusions is concerned with the microscopic, microthermometric analysis of fluid inclusions in various rocks and minerals, especially from the hydrothermal environment. Based on the obtained data, the temperature and pressure conditions of the origin of fluid inclusions and the composition and density of palaeofluids can be determined.

As a strong member of our team, Dr. Jana Kotková is involved in study of genesis and evolution of magmatic and metamorphic rocks using a large range of micro- and nano-techniques and mineralogical, petrological and geochemical methods.

Section 234 – Isotope Geochemistry and Geochronology

This section conducts analyses of the Sr, Nd, Pb, and Li isotopic systems in geologic materials, using mass spectrometric methods (TIMS and MC-ICPMS). Laser ablation (LA-ICPMS) is used for zircon dating and in-situ point analyses of trace elements. In cooperation with the Geological Institute of the Czech Academy of Sciences (GI AV CR), it carries out Os isotope analyses. The data generated are not only used in projects within CGS, but form the basis for cooperation with other institutions. These projects address a wide variety of topics that depend on geochemistry of igneous and metamorphic rocks, and many are interdisciplinary studies. Researchers within this section are also active in the fields of methods development and mathematical modeling of geochemical data.

Section 235 – Ultratrace laboratory

The ultra-trace laboratory of the CGS (in operation since 2008) is a positive-pressure, filtered air clean room (class ISO 7) that has regulated temperature and humidity. It is used for sample preparation necessary prior to determination of isotopic ratios via mass spectrometry (TIMS, ICPMS). This involves digestion and separation of the element(s) of interest from matrix using ion exchange column chromatography.

Section 236 – Section of X-ray diffraction

The work of this section is mainly concerned with x-ray powder diffraction. The laboratory carries out semi-quantitative modal and structural analyses of geological and synthetic materials. Ternary systems containing chalcophile elements and the study of synthetic analogues of minerals of the platinum group metals (PGM) are among the major topics under investigation by the staff of this laboratory. The mineralogy of clays and their interactions in the natural environment is another important theme under investigation.

Section 237 – Biodiversity and global changes in geological history

In this laboratory a number of special methods are used to separate microfossils (plankton, spores, pollens, conodonts, scolecodonts, and chitinozoa) from sediments of various geological ages. The major interests of the scientists involved are the causes of global environmental changes in the geological past and their influence on marine and terrestrial ecosystems. In addition to basic taxonomy and biostratigraphical research the team is involved in developing applied methods of palaeobiological analysis of fossil communities, analysis of evolutionary rates, isotope geochemistry, and problems of analysis of microfacies and sequencestratigraphy. The results from miscellaneous geoscientific disciplines are used as a “proxy” for creating models of environmental change.