Coal ball
Torfdolomiten are concretions of permineralisiertem peat, which are found in coal seams. They appear as roughly spherical nodules or as irregular flat plates. Torfdolomite caused by the Permineralisierung of peat by calcite in swamps of the Carboniferous before conversion to coal. This will provide detailed information on the structure of the plant tissue of the carbon that would have been lost during the carbonization.
Torfdolomiten were first described in 1855 by the scientists Joseph Dalton Hooker and Edward William Binney in England. They occur in North America and Eurasia. In North America, they were first described in 1922 by Carl Adolf Noë; there they are both more widespread stratigraphically geographically. The oldest known Torfdolomiten come from the Namurium and were found in Germany and the former Czechoslovakia. The investigation of Torfdolomiten has led to the discovery of hundreds of species and genera.
Early scientific theories
Torfdolomiten were first described by Joseph Dalton Hooker and Edward William Binney scientifically. They reported on specimens from the coal seams of Lancashire and Yorkshire. Many of the early work on Torfdolomiten come from European scientists.
In North America Torfdolomiten were first found in 1894 in the coal seams of Iowa, but only in 1922 brought by Adolf Carl Noë with European Torfdolomiten in conjunction. Noë publication sparked a renewed interest in Torfdolomiten, and in the 1930 European palaeobotanist traveled in search of Torfdolomiten the Illinois Basin.
There are two theories - the indigenous in-situ theory, and the Allochthonous drift theory - the attempt to explain the origin of Torfdolomiten, although this topic is often speculative.
Supporters of the in situ theory believe that organic material near its reference is collected in a peat bog and shortly after it was buried, was permineralisiert - Minerals invaded the organic matter and formed an internal cast. Water with a high content of dissolved minerals was buried along with the plant material in the bog. When the dissolved ions crystallized to plant material containing concretions, which were preserved as rounded stone lumps formed. Thus, the coalification was prevented, and the peat was preserved and eventually formed a Torfdolomiten. Most Torfdolomiten be found in Steinkohleflözen, at sites where the peat has not been sufficiently compressed to turn into charcoal.
Marie Stopes and David Watson Torfdolomit analyzed samples and decided that Torfdolomiten form in situ. They emphasized the importance of the interaction with sea water, which they considered as a necessary condition for the formation of Torfdolomiten. Some supporters see the in situ theory in Stopes and Watson's discovery of a plant stem which extends through several Torfdolomiten, a proof of the in situ theory, since the drift theory, this observation could not explain. They also point to fragile parts organic material sticking out of some Torfdolomiten and would be the drift theory is correct, would have had to be destroyed. Finally, some Torfdolomiten are so large that they are not portable.
According to the drift theory, the organic material was not formed near the location, but was transported by a flood or a storm there. Supporters of the drift theory as Sergius Mamay and Ellis Yochelson believed that the occurrence of marine animals in Torfdolomiten Prove that material was transported from the sea in a non -marine environment. According to Edward C. Jeffrey had the in situ theory " no good evidence"; he believed that the formation of transported material was likely because Torfdolomiten often contain materials that occur in open water by transport and sedimentation.
Composition
Torfdolomiten not consist of coal. They are non-flammable. They are calcium-rich permineralisierte life forms that contain mostly calcium and magnesium carbonates and pyrite and quartz. In lesser amounts also gypsum, illite, kaolinite and lepidocrocite occur. The size of Torfdolomiten varies from the size of a walnut to a diameter of 90cm; usually they are big as a fist. It also Torfdolomiten were found that were smaller than a thimble.
Torfdolomiten contain dolomite, aragonite and amounts of different degrees decaying organic material. Hooker and Binney analyzed a Torfdolomiten and noted "a lack of koniferenartigem wood and fern fronds ... "; the plant material discovered seemed so arranged " just as it fell from the plants that produced it ." Usually get Torfdolomiten no leaves.
1962 studied Sergius Mamay and Ellis Yochelson North American Torfdolomiten. After they discovered marine organisms Torfdolomiten were divided into three types: regular (also floral ) containing only vegetable material; faunal containing only animal fossils, and mixed, containing both plant and animal material. The mixed were divided into heterogeneous, where plant and animal material templates separated and homogeneous, which had no such separation.
Degree of conservation
The degree of preservation of organic material in Torfdolomiten fluctuates between no conservation to such good condition that the cell structures could be examined. Some Torfdolomiten received root hairs, pollen and spores, and are described as " received more or less perfect "; they do not contain " what was once the plant was " but the plant itself are other " botanical worthless "; the organic material had decomposed before it became the Torfdolomiten. Well-preserved Torfdolomiten are useful for palaeobotanist. They were used to investigate the geographical distribution of vegetation, and provided evidence that the tropical belt in Ukraine and in Oklahoma the Cretaceous period, the same plants grew. Torfdolomiten research also led to the discovery of more than 130 genera and 350 species.
Three main factors determine the quality of the obtained material in a Torfdolomiten: The mineral composition, how quickly the material was buried, and how strong it was compressed before Permineralisierung. Generally Torfdolomiten of hardly decomposed material that was quickly buried under low pressure, the best preserved; however, shows plant material in Torfdolomiten almost always some trace of digestion. Torfdolomiten containing iron sulfide, are significantly worse than obtained Torfdolomiten that were permineralisiert by magnesium - or calcium carbonate; Therefore, iron sulfide was also called the " Curse of the main Torfdolomit hunter".
Distribution
Torfdolomiten were first discovered in England, then in other regions including Australia, Belgium, the Netherlands, the former Czechoslovakia, Germany, Ukraine, China and Spain. They also occur in North America; there are more geographically dispersed than in Europe. In the U.S., they were found from Kansas to Illinois Basin and the Appalachian Mountains.
The oldest Torfdolomiten dated to the beginning of the final phase Namurium (before 326-313 million years ago); they were found in Germany and the former Czechoslovakia. The usual age is between the Permian ( 299-251 million years ago ) and the Pennsylvanian. Some American Torfdolomiten come from layers between the late Westfalium (in about 313-304 million years ago) and the late Stefanium ( million years ago, about 304-299 ). European Torfdolomiten usually originate from the early Westfalium.
In coal seams Torfdolomiten are completely surrounded by coal. They are often found in randomly distributed in the seam, isolated groups, usually in the top half of the seam. Their occurrence may be extremely rare or common; many coal seams contain no Torfdolomiten, while some contain so many that miners avoid the areas.
Methods of investigation
Thin section was an early method for the study of fossil materials in Torfdolomiten. For this purpose a Torfdolomit was cut with a diamond saw and smoothed the thin disk and polished with an abrasive cleaner. Thereafter, it was observed under a polarization microscope. Although this process could be mechanized, it was replaced by a more convenient method because of the high time requirement and the poor quality of the samples prepared by thin section.
1928 sparked the still common liquid splitter technology ( "liquid peel" ) from the thin section. Samples are cut with a diamond saw, polished with silicon carbide on a glass plate and etched with hydrochloric acid. The acid dissolves the minerals from Torfdolomiten so that a protruding position from plant material remain on. After the application of acetone a piece of cellulose acetate is placed on the Torfdolomiten. This received in Torfdolomiten cells are embedded in the cellulose acetate. After drying, you can remove the acetate with a razor blade from Torfdolomiten and color the resulting splinter with a weakly acidic dye and observed under the microscope. In this way, up to 50 samples can be obtained from a 2 mm thick Torfdolomitstück.
However, the samples degrade over time if they contain iron sulfide ( pyrite or marcasite ). Shya Chitaley resolved this problem by using of the inorganic minerals, including iron sulfide, improved separation of the organic material is conserved. Thus the sample retains its quality for longer. At Chitaleys method of polishing, the sample is heated and repeatedly treated with solutions of wax in xylene, where the paraffin concentration increases with each treatment, so that the wax can fully penetrate the Torfdolomiten. Thereafter, the sample is treated with nitric acid and acetone. Then Chitaleys technique is similar to the conventional liquid splitter technique again.
Also, X-ray diffraction in Debye- Scherrer method was used for the investigation of Torfdolomiten. X-rays of a predetermined wavelength can be passed through a specimen in order to investigate their structure, in particular the crystallographic structure, the chemical composition and physical properties. The intensity of the diffracted X-rays are observed and analyzed, the measured values of incident and diffraction angles, polarization and wavelength ( energy ) are made.