Organic matter associated with rocks was examined by means of thermal analysis using a new methodology in oxidising conditions.
This procedure has been named “Oxyreactive Thermal Analysis” (OTA). The OTA results presented in this study characterise samples
from sedimentary rock complexes in terms of their age, and of variations in the associated organic matter arising from different
precursors and degree of severity of subsequent transformation processes to which it has been subjected.
The results of the OTA method make it possible to estimate the temperature of maturation, to describe the process of evolution
of the organic matter, and to distinguish genetic features of its carbonised and metamorphosed products.
The influence of certain experimental conditions on the courses of the thermal curves (DTA and DTG) of selected clay minerals
was studied. The thickness of the sample layer, the sample mass, the type of sample holder and the parameters of the air atmosphere
were varied in thermal analyses of 13 samples of clay minerals. Comparison of the results obtained on different clay samples
analysed under different experimental conditions may serve as the basis for the improvement of the thermal analysis methodology
applied for the study of clay minerals.
Authors:S. Cebulak, A. Langier-Kuüniarowa, and I. Grotek
Oxyreactive thermal analysis (OTA) carried out in the conditions of full access of oxygen to each reacting particle of the sample investigated is a suitable method for the determination of important properties of the organic matter dispersed in the rocks. Its results may be easily evaluated to the form of values to be used in a clear diversification and classification system of organic matter/kerogen, as well as to the evaluation of its transformation process in a rockmass. The OTA also enables the distinguishing of the transformation stages and the investigation of the results of the gaseous products liberation from organic matter and kerogen. The OTA method may be applied as a complementary one for the Rock Eval analysis and be used for the organic geochemical and bituminological studies for geological bitumen prospecting.
Authors:S. Cebulak, A. Matuszewska, and A. Langier-Kuźniarowa
The paper presents the applicability of oxyreactive thermal analysis (OTA) for the investigation of different kinds of resins
both natural (recent and fossil) and synthetic. For comparative reasons and a more precise interpretation, along with OTA
infrared spectroscopy was used as a method commonly applied for the investigation of fossil resins. The results obtained prove
that the OTA method may be very useful for diversification of different kinds of resins. The parameter most valuable for the
preliminary characteristics of resins and the evaluation of their transformation was found to be the mass loss recorded on
TG curves in three definite temperature ranges.
Authors:S. Cebulak, A. Gawęda, and A. Langier-Kużniarowa
This paper presents the results of oxyreactive thermal analyses of organic matter in rocks, heated naturally during diagenetic
to metamorphic processes. During the experiments we traced the reactions in the temperature range up to 900C, it means from
the very beginning of diagenetic transformations to the highest real temperatures acting in the Earth's crust as a solid phase.
The results showed that TA could be a tool for the reconstruction of thermal regime in natural coal-bearing systems.
Authors:S. Cebulak, A. Karczewska, A. Mazurek, and A. Langier-Kużniarowa
The study presents examples of the application of oxyreactive thermal analysis to the geological prospecting of bitumen deposits. Thermal analysis performed under properly chosen analytical conditions allows determination of characteristic features of organic matter and, at the same time, estimation of the thermal history of rocks. Thermal oxyreactivity curves document whether rocks were heated before or not. The results of the oxyreactive thermal analysis correlate well with the results of routine chemical analyses of organic matter (e.g. the composition of kerogen and bituminous fraction, Rock-Eval analysis and others). Our study clearly demonstrates that the composition of organic matter in facially, lithostratigraphically, and biogenetically identical rocks depends on their thermal history.
Authors:S. Cebulak, A. Langier-Kuźniarowa, G. Czapowski, and G. Bzowska
The paper discusses the influence of variable experimental conditions on the thermal decomposition of carbonate minerals.
This study was based on Ca-Mg carbonate minerals from Upper Permian dolomite and zuber rocks as well as on calcite and magnesite
samples from geological formations of various ages. X-ray diffraction was applied for comparative purposes. Experimental conditions
were chosen based on the authors' experience related to studies of both fossil and contemporary organic matters as well as
various materials of geological provenience. Since the main factor in thermal analysis of carbonates is the appropriate choice
of experimental conditions for outflow of gaseous reaction products, the thermal analyses were carried out with various sample
holders, various sample masses and varied thickness of sample layers in holders, using also a dynamic atmosphere. The results
obtained indicated that different experimental conditions produced extremely different TA data, e.g. the traditional analysis
in crucible sample holders with a thick sample layer (great sample mass) showed well expressed double thermal effects of dolomite.
For thin sample layer both peaks of thermal decomposition of carbonate components occurred in very close or almost identical
temperatures. The presented results enabled to devise a detailed procedure referring to the choice of experimental conditions
and interpretation possibilities as well as to recommend specific TA instruments design and sample holders types.
Authors:S. Cebulak, B. Smieja-Król, S. Duber, M. Misz, and A. Morawski
The paper presents the applicability of Oxyreactive Thermal Analysis (OTA) for the investigation of different kinds of carbon
matter. For comparative reasons and more precise interpretation, along with OTA some physico-chemical properties of analyzed
materials were used as the methods commonly applied for the investigations.
The carbon materials of both natural (anthracites, graphite and diamonds) and synthetic origin (active carbon, glass carbon,
expanded graphite, soot and synthetic diamonds) were investigated.
It was stated that there is close relationship between structure parameters and physico-chemical properties and the thermal
reactivity within the investigated groups of carbon matters. The results show that OTA can be accepted as a good investigative
way for such materials.