Palynological, organic-petrographical and organic-geochemical investigations on coals and sediments of the Duckmantian, Ruhr Basin, Germany [Elektronische Ressource] / vorgelegt von Kai Jasper

Dino Esposito

Informations

• Publié par: rheinisch-westfalischen_technischen_hochschule_-rwth-_aachen
• Publié le: 01 janvier 2009
• Nombre de lectures: 18
• Langue: English
• Poids de l'ouvrage: 6 Mo

Extrait

Palynological, organic-petrographical and organic-geochemical
investigations on coals and sediments of the Duckmantian, Ruhr Basin,
Germany

Von der Fakultät für Georessourcen und Materialtechnik
der Rheinisch -Westfälischen Technischen Hochschule Aachen

zur Erlangung des akademischen Grades eines
Doktors der Naturwissenschaften

genehmigte Dissertation

vorgelegt von
Dipl.-Geol. Kai Jasper

aus Minden (Westfalen)


Berichter: Univ.-Prof. Dr. rer. nat. Ralf Littke
Univ.-Prof. (i.R.) Dr. phil. Gerd Flajs

Tag der mündlichen Prüfung: 22. Dezember 2009
Diese Dissertation ist auf den Internetseiten der Hochschulbibliothek online
verfügbar
 
















This thesis is dedicated to my parents,
who sponsored my studies over many years
and enabled me to finish this work
and to Rahel, whom I love.  
Acknowledgements

First of all I wish to thank my supervisors Prof. Dr. G. Flajs and Prof. Dr. R. Littke for proposing this
project to me, for their support, and for the opportunity to complete my thesis. I would also like to
express my gratitude to them for their technical and financial support and many discussions on a vast
number of disciplines.
In addition, I gratefully thank C. Hartkopf-Fröder from the Geological Survey of NRW, who was one
of the primary proponents of this work and co-supervisor of my thesis, for his constructive discussions
and feedbacks, technical support, innovative ideas and many other things, which helped me to finish
this work.
Furthermore, I thank Dr. Bernd Krooss for his support on chapter 2 and Prof. Dr. Jan Schwarzbauer
for his discussion on chapter 4. I also thank Dr. Duncan McLean for many discussions on
Pennsylvanian miospore taxonomy as well as PhD. Chris Cleal and PhD. William DiMichele for many
constructive comments on chapter 3. Chapter 3 of this thesis is a contribution to IGCP 469: Late
Variscan terrestrial biotas and palaeoenvironments.

For the preparation of high-quality polished sections for maceral analyses I acknowledge Rolf
Mildenberger. For further technical support and some discussions, I would like to thank Tom
Frauenrath, Martin Haake, Anke Jurisch, Jens Köster, Werner Kraus, Anna Uffmann, Philipp
Weniger, and Kathrin Windeck.
Moreover, I want to thank Prof. Dr. K. Reicherter for allowing me to stay in his department for a
further time and who also assisted me with regards to financial and administrative challenges during
this time.

For the financial support of this project (grants No Fl131/14) I gratefully acknowledge the DFG
(German Research Foundation). I would also like to express my appreciation to the RAG-Deutsche
Steinkohle and DMT (Deutsche Montan Technologie) for samples and technical support.
For administrative support, I am especially thankful to all the secretaries, who supported me during the
last five years: Bettina Lesmeister, Evelyn Bützler, Dorit Karnelis, Dorothee Degen and Olga Schefler.

Finally, I want to thank all my colleagues for the time I enjoyed with them, especially Maggie, Gösta,
Grütze and Werner – I will never forget the fantastic time in the Palaeo/NUG!


V
 
Abstract

The idea of the present thesis was to combine different established methods in a high-resolution study
on a short-timed interval of Duckmantian strata (Pennsylvanian/Upper Carboniferous) of the Ruhr
Basin, Western Germany. Organic petrographical, palynological, sedimentological and organic
geochemical techniques were used to obtain a huge data set, to support the argumentations and
discussions. In doing so, these investigations were focused on two main goals: (a) the maturity and
quality of source rocks and (b) the evolution of swamp environments.

For this study, six coal-bearing seam successions were examined. Fresh drilling material was provided
by the DSK coal mine Prosper Haniel in the Ruhr Basin, western Germany. All samples were taken
from two multilateral wells. Experimental investigations comprise the following techniques:
Sedimentological core description, maceral analyses, vitrinite reflectance, TOC, ash and Rock-Eval
pyrolysis on sediments, kerogen concentrates and coal-mineral-mixtures, palynological investigations
on miospores, and GC analyses on n-alkanes, and iso-alkanes.

(a) Maturity and quality of source rocks

This first part of the study focuses on the quality, quantity and maturity of coal and dispersed
terrigenous organic matter. Furthermore, kerogen concentrates and coal-mineral-mixtures also were
analysed.
For the sampled interval samples show a vitrinite reflectance between 0.75 and 1.0 % with an increase
of maturity towards the stratigraphic older and deeper seam successions. Average vitrinite reflectance
of sediment samples is slightly higher than that of coal samples. The maturity trend also is reflected in
the T values of Rock-Eval pyrolysis or the C /C -relationship. max 17 27
Investigations on petroleum potential show a kerogen type III respectively II/III for the sampled
interval. Differences between Rock-Eval parameters determined on whole rock samples and kerogen
concentrates were observed, especially with respect to Hydrogen Index (HI) values. In coals, which
were compared with dispersed organic matter of similar maceral composition, the HI is about two
times as high as that of the sediment samples. In contrast, Oxygen Indices are much higher for
dispersed type III kerogen than for coal, caused by the stronger degradation of organic compounds in
the clastic environments as compared to the peat environments. However, Oxygen Indices clearly are
influenced by decomposition of carbonate minerals. Furthermore, Hydrogen Indices of dispersed
kerogen are influenced by mineral-matrix effects. Experiments with artificial mixtures of coal and
minerals show that reactions with pyrite seem to reduce HI values of kerogen concentrates
significantly.

VII

(b) Evolution of swamp environments

The second part of the thesis focuses on palynological investigations on miospores to reconstruct the
swamp evolution during the Duckmantian of the Ruhr Basin. In addition, sedimentological and
organic petrographical data confirmed the interpretation.
Based on published information of in situ spores the encountered miospores were assigned to their
parent plants in order to reconstruct the vegetation history. In this study six plant associations were
identified by using a Detrended Correspondence Analyses (DCA): lepidocarpacean association I,
lepidocarpacean association II, lepidocarpacean – sigillarian association, lepidocarpacean –
sphenophyll association, lepidocarpacean – fern association, and the subarborescent lycopsid
association. Furthermore, coal petrographical GI/TPI and GWI/VI relationships also reflect these
associations. Another new defined index, the water cover index (WCI), based on these palynological
interpretations, reflects the ratio of hydrophilous/hygrophilous vs. mesophilous plants and gives
additional information on the environment.
In the sampled seam successions arborescent lycopsids are the most abundant plants, with a
dominance of the miospore Lycospora. In 75 % of all samples the genus is represented with more than
50 % relative abundance. Hence, lepidocarpaceans such as Lepidophloios and Lepidodendron
dominated the vegetation of the Ruhr Basin during the mid and late Duckmantian, forming flood
plains and planar forest mires. Some variations are reflected in abundance of other spores. A greater
influence of the sigillarian miospores Crassispora was typical for drier swamp margins, whereas
densospore producing plants or sphenophylls characterized the stunted respectively scrambling
vegetation of domed swamps. By contrast, fern influenced environments were rare during the
Duckmantian.
Recurring rhythmic successions of plant associations and depositional environments were noted in the
studied interval: A lower flood plain is followed by peat substrate topogenous mires, which rise up and
build an ombrogenous mire. After subsidence and recurrent flooding an upper flood plain was re-
established. This general cycle is temporarily interrupted by other plant associations representing
varying local environments. Drier sandbanks and swamp margin zones covered with sigillarians
regularly occurred, implicating small environmental variations and a lateral shift of the swamp habitat.


VIII

Zusammenfassung

Die Grundidee dieser Arbeit war die Kombination verschiedener Analyse-Methoden zur
Durchführung einer hochauflösenden Studie. Hierfür wurde ein sehr kurzes Zeitintervall im
Duckmantium (Pennsylvanium/Oberkarbon) des Ruhrbeckens/Deutschland ausgewählt. Die
Anwendung von organsicher Petrographie, Palynologie, Sedimentologie sowie organischer
Geochemie ermöglichten die Aufnahme eines sehr umfangreichen Datensatzes, dem eine statistisch
gestützte Ergebnisdiskussion folgte und die zwei Hauptzielsetzungen hatte: (a) Reife und Qualität von
Source Rocks und (b) Entwicklung