Lower Rhine Basin Research Articles

Accumulation of copper in the Permian Kupferschiefer: A result of post-depositional redox reactions

Within the Central European Zechstein Basin the Permian Kupferschiefer has been deposited under anoxic conditions. In most parts of the basin, the metal content does not exceed values commonly observed in black shales. However, in areas near to the Zechstein sea-shore which are simultaneously related to rift zones a significant base metal enrichment is observed. Organic geochemical analyses of the copper-mineralized sections in the Kupferschiefer from Southwest Poland show that significant changes in the composition of organic matter are associated with the metal enrichment processes. Porphyrins, commonly abundant constituents of the shale, have been decomposed by oxidizing fluids. Additionally, aliphatic hydrocarbons have been largely removed from the bitumen and alkylated aromatic systems were affected by side-chain degradation. This particular type of alteration is explained by ascending oxidizing solutions which transported high amounts of base metals from Lower Permian red beds into the Kupferschiefer horizon acting as a geochemical trap. The metal precipitation is suggested to be a result of thermochemical sulphide production with organic matter acting as hydrogen source. In areas such as the Lower Rhine Basin in the bottom section of the Kupferschiefer the base metals lead and zinc as well as barium have been accumulated from basinal Carboniferous formation waters. Copper enrichment is not observed because potential source rocks are missing in this area. However, the observed compositional changes of the organic matter do not point towards thermochemical redox processes.

Structure and origin of terpenoid hydrocarbons in some German coals

Abstract Hydrocarbon extracts of coal samples from major coal fields in West Germany have been investigated by gas chromatography-mass spectrometry (GC/MS). The samples are of Carboniferous and Tertiary age and derive from limnic and paralic environments, the Saar District, the Ruhr Area and the Lower Rhine Basin. Differences in facies, maturity and age reflected in the distribution patterns of the extracted alkylcyclohexanes. An unexpected occurrence of cyclic diterpenoid hydrocarbons in some samples of Carboniferous age has been found. The tetracyclic compounds mainly show phyllocladane type structures and can serve as source indicators. Hydrocarbons obtained from chemical degradation of the macromolecular material of the samples also revealed phyllocladane-type compounds which are normally associated to resins of modern and extinct familes of conifers. Origin and structural variations of this class of hydrocarbons are discussed in terms of maturity and palaeobotanical implications.

Aromatic hydrocarbon composition of the Permian Kupferschiefer in the Lower Rhine Basin, NW Germany

The aromatic hydrocarbon composition of 25 samples of Permian Kupferschiefer from the Lower Rhine Basin of NW Germany has been investigated using GC, GC/MS and direct probe MS analysis. Two narrow-sampled profiles were investigated with respect to compositional changes during Kupferschiefer sedimentation and samples from 13 different wells, covering a depth range from 350 to 1000 m, were included in order to study temperature-sensitive variations. In the Kupferschiefer trimethyl-substituted aryl isoprenoids in the range from C 11 to C 21 occur. These compounds presumably are degradation products of isorenieratane, which is also present in the extracts. Within the profile the amount of a preferentially occuring C 29-chroman increases from the bottom to the top of the Kupferscheifer by a factor of about 2.5. The chroman distribution observed in the Kupferschiefer points towards euhaline to mesohaline seawater during sedimentation. Moreover, in the investigated profiles a terrestrial source input mainly in the bottom-most part of the shale is reflected by the occurrence of a monoaromatic C 24-chrysene derivative, presumably derived from ring-A-degradation of pentacyclic triterpenes.

Facies and rank of the Permian Kupferschiefer from the lower Rhine basin and NW Germany

The Kupferschiefer of the Lower Rhine Basin and of NW Germany is a typical black shale containing C org values between 0.5 and 9.1%. On average it contains 4% C org. In coal petrographic terms the organic matter of the Kupferschiefer is characterized by well preserved liptinite as sporinite - especially derived from the pollen grains of conifers - in the area of the Lower Rhine Basin and as alginite towards the centre of the Kupferschiefer sea. The high content of bituminite in all of the samples shows that the main source of organic matter is derived from plancton and bacteria. Vitrinite and inertinite are rare. The rank of the organic matter in the sediment varies between the lignite stage (Lower Rhine Basin) and the bituminous coal stage (NW Germany). Geochemical investigations have shown that residual heat from the Krefeld High was active until the lower Zechstein. This has caused a change in the chemical composition of the organic matter but did not express itself in the optical parameters. Inhomogeneities of the organic matter in low-rank and bituminization in higher-rank materials influence the vitrinite reflectance. Fluorescence measurements are more sensitive in sapropelic sediments and oil shales than vitrinite reflectance. It is evident that the red/green ration is more reliable in view of diagenesis studies than the lambda max of the fluorescence spectra. Geochemical parameters are partly much more sensitive towards thermal stress as compared to vitrinite reflectance, e.g. metalloporphyrin concentrations decrease with increasing temperatures. The parameter covers a temperature range from ca. 40°C to 80°C. The weighted average mass of the vanadyl-cycloalkano-porphyrins is suitable to characterize the influence of temperature on the Kupferschiefer between ca. 40°C and 150°C. Summing up, the Kupferschiefer of the Lower Rhine Basin in NW Germany is a sidiment very well suited for parallel petrographic and organic-geochemical research. The results of this might be also of interest in the field of oil prospecting.

The Kupferschiefer; an overview with an appraisal of the different types of mineralization

The Kupferschiefer; an overview with an appraisal of the different types of mineralization

Use of biological marker distributions to study thermal history of the Permian Kupferschiefer of the Lower Rhine Basin

In the Central European Zechstein Basin, the Permian Kupferschiefer has been deposited under marine anoxic conditions. From a lagoon at the southwest border of the Zechstein Sea, today part of the Lower Rhine Basin, 30 core samples have been studied by means of organic geochemical methods. Within the area investigated, the depth of the Kupferschiefer horizon increases from about 350 m in the south to about 1000 m in the north. Furthermore, the Kupferschiefer has been thermally affected in the western part by the intrusive body of the so-called Krefeld High. This geological situation opens the possibility to investigate differences of short term and long term temperature effects on the biological marker distribution within a sediment layer of a largely uniform facies type. Depth related changes in the hopane, sterane and diasterene/diasterane distributions are compared to those changes induced by the Krefeld High. The composition of aromatic steroid hydrocarbons is used to discuss time-temperature effects. It is shown that depth related values of maturation parameters can only be interpreted by taking into account post-depositional tectonic events. Samples from tectonic horst structures show higher maturation values than one would expect from the present day depth.

Iron porphyrins in the Permian Kupferschiefer of the lower Rhine Basin, N.W. Germany

Immature samples of the Permian Kupferschiefer from the Lower Rhine Basin in N.W. Germany were analysed for tetrapyrrole pigment type and abundance. The sediment, thought to have been deposited in a marine regime with enhanced salinity, was found to contain high concentrations of metalloporphyrins. The porphyrins are complexed to nickel (Ni) and oxovanadium (V=0), but high abundances of iron (Fe) porphyrins were also detected using UV/visible spectroscopy and mass spectrometry. The presence in the latter of series of aetioporphyrins, cycloalkanoporphyrins, di-cycloalkanoporphyrins and benz-cycloalkanoporphyrins was confirmed by accurate mass measurements; HPLC co-injection of deoxophylloerythroetioporphyrin (C 32 DPEP) with the demetallated iron porphyrins indicated its presence in the sediment as an iron complex. The study provides the first evidence for the occurrence of Fe porphyrins in geological samples other than coals and lignites, and reports the highest concentrations in sedimentary organic matter to date.

Influence of an intrusion on the extent of isomerism in acyclic isoprenoids in the Permian Kupferschiefer of the Lower Rhine Basin, N.W. Germany

The intrusive body near Krefeld, North-West Germany, the so-called Krefeld High, is known to have increased the coalification of the Carboniferous coal seams in the western part of the Ruhr coal mining district. However, no evidence of its influence on the partly overlying Permian sediments has been given to date. Therefore, organic geochemical investigations on the extractable organic matter from 30 core samples of the Permian Kupferschiefer covering an area of about 600 km 2 were undertaken. The determination of selected molecular maturation parameters reveals a low average maturation of the Kupferschiefer within the area investigated. Locally varying thermal effects could be measured by the extent of isomerism of pristane and phytane. In an area not affected by the intrusive body the extent of isomerism is shown to be influenced only by the burial depth and by some minor tectonic events. In the proximity of the Krefeld High, the extent of isomerism is significantly higher than expected from the actual burial depth. The extent of pristane and phytane epimerisation have been used to deduce isolines for the characterisation of thermal effects in the area investigated.

Correlation of Plio-Pleistocene deposits of the Lower Rhine Basin (North-West Germany) and the Valle Ricca pits (Central Italy)

Biostratigraphic and palaeomagnetic research has been carried out on selected profiles in North-Western Germany and Central Italy in order to correlate Plio-Pleistocene sections. Around the Réunion subchronozone, vegetation in the Valle Ricca was dominated by a mountain forest type pointing to cool climatic conditions. In the Lower Rhine Basin vegetation had a slightly warmer character, but was also dominated strongly by a mountain type of forest vegetation, characteristic of cooler summers and higher precipitation than at present. Two warmer periods have been determined in the Central Italian profiles; the youngest around the Olduvai reversal, should correspond to the youngest Tiglian beds of the Lower Rhine Basin. Deposits older than the Réunion subzone have not been found in the Valle Ricca. In the Lower Rhine Basin, on the other hand, the Gauss-Matuyama boundary is located between the uppermost Pliocene, the Reuverian C and the Praetiglian.

Allochthonous seed and fruit floras from the pliocene of the lower rhine basin

Pliocene seed and fruit floras are described from sand-filled river channels in the browncoal pits “Fortuna-Garsdorf” near Bergheim, “Frechen” near Frechen and “Hambach” near Düren. They include 103 identified species, divided over 71 genera of gymnosperms and angiosperms. One new species based on seeds or fruits is formally described: Oxydendrum europaeum. The floras are compared with Miocene and Pliocene floras from Western, Central and Eastern Europe. A new method for quantitative comparisonso f fossil floras is presented.

Die Tiefenlage der Salzwasser-Süßwassergrenze in der südlichen Niederrheinischen Bucht

Die Tiefenlage der Salzwasser-Süßwassergrenze in der südlichen Niederrheinischen Bucht

Hydrochemische Grundlagen für künstliche Grundwasseranreicherungen im Südteil der Niederrheinischen Bucht

Hydrochemische Grundlagen für künstliche Grundwasseranreicherungen im Südteil der Niederrheinischen Bucht

SEDIMENTSTRUKTUREN AUS DEN NIEDERRHEINISCHEN BRAUNKOHLENSCHICHTEN DES MIOZÄNS

SUMMARYSedimentary structures in the Miocene fluviatile deposits of the Lower Rhine Basin, lying immediately beneath the lignite formations have been studied at Tagebau Frechen near Cologne. The structures investigated include slump structures, load casts, clay breccia, cross‐bedding, sand fabric and orientation of driftwood.The slump structures are composed of alternating laminae of clay and silt and have resulted from sub‐aquatic sliding of a sedimentary sheet over a surface of erosion or of a foreset bed of 10–20° inclination. The slumping has caused folding or brecciation of the strata involved.The base of a sand bed is difficult to obtain as the sediment is weakly consolidated. Load casts, therefore, have been studied exclusively in their internal structure. It is considered that the load casts of smaller dimensions have suffered a diminution of relief through settlement after the process of load casting had ceased.Two types of clay breccia have been recognised, namely those which have undergone erosion and transportation by water and those which have resulted from slumping.In an exposure, tabular‐ and trough‐type of cross‐bedding alternate with each other in geological succession. From these examples sand fabrics have been studied. Both in tabular‐ and trough‐type of cross‐bedding the apparent long axes show two maxima. In the former case, these maxima are disposed to each other at an acute angle, in the latter case, however, they are perpendicular to each other. Imbrication, after tilting the Sf‐to original position, is down‐current in tabular cross‐bedding. In trough type, on the contrary, it may be upcurrent or the long axes of the grains dip symmetrically in up‐ and down‐current direction.

Zur Gliederung mittel- und jungpleistozäner Schichten in der Niederrheinischen Bucht

Abstract. From the waterworks of Bensberg east of Cologne and a gravel-pit near Efferen west of Cologne, there have been described layers of clay and fine-sand, containing fossils with humus layers from a depth of about 16 to 18, 20 meters below the surface of the Lower Middle-Terrace of the Rhine (i.e.: about 58 m above sea-level). These sediments enable us to separate stratigraphically in the sand-gravel-sequences the overlying from the underlying stratum one. Heavy mineral analysis shows, that the underlying series belongs to the Middle Middle-Terrace of the Rhine (of Late-Mindel-age). The distribution of this terrace within the Lower-Rhine-Basin thus cannot be limited only to some narrow channels („Channel-Gravel"), but is supposed to be developped over the whole breadth of the valley, like in the Middle-Rhine-Valley, yet here buried under sediments of the Lower Middle-Terrace. The palynologic investigation of the humus layers within the clay and flnesand-layers of the waterworks of Bensberg shows a flora indicating a late-interglacial age by their high percentage of Abies-Alnus-Picea-values. According to the stratigraphical findings they can only be attached to the Mindel/Riß-interglacial Krefeld-Beds. The investigations carried out led to a critical examination of the existing attempts of difTeren-ciating the Middle-Pleistocene beds in the Lower-Rhine Basin. The Kempen and Neuwerk Beds have to be separated from the Krefeld Beds, according to both the stratigraphic and the floristic and faunistic findings, and must be attached to the Gerdau-Interstadial, the first one probably belonging to a late and the latter (much more probably) to a middle part of this Drenthe/Warthe-Interstadial. The authors try to give a climatic-chronologic table of all Middle Pleistocene beds in the Lower-Rhine-Basin.