Geographic archive
A geographic archive is an object that modern geosciences can use to obtain data for the reconstruction of the geological past. This actually includes all exposed or drilled rocks as well as the structures, minerals , fossils or fluid and gas inclusions contained therein . Ice cores that contain pollen and air from past millennia are also part of the geo-archives. In a broader sense, every known and directly researchable geological and geomorphological structure can be understood as a more or less complex geographic archive.
meaning
Only the investigation and evaluation of geo-archives makes it possible to understand the current state of animate and inanimate nature and, under certain circumstances, even to make predictions for the future. The historical beginnings of paleontology ("petrefacts") and geology ("geognosy") were already characterized by attempts to locate the geological past of the earth locally, regionally and partly also globally from the available material, primarily the rocks and fossils, read within the scope of the possibilities at the time. In the course of time, geology and paleontology have developed into modern, highly differentiated empirical sciences , but their most important main task (with the exception of a few sub-areas) is still the evaluation of geo-archives and the development of new methods for this purpose. The actualism principle and experimental geology were and are an important means of deciphering the information contained in geo-archives. One can say that almost everything that is known about the past of the system earth , on a small as well as on a large scale, ultimately comes from the study of geo-archives.
Methods (examples)
Paleontological and geological reconstructions are always complex puzzles. The older a geographic archive is, the more patchy the data that can be obtained from it and the more difficult it is to interpret it clearly and to create a detailed reconstruction from it.
For the detailed reconstruction of the geological history of a particular region, among other things, knowledge of the local and regional stratigraphic conditions, including the presence of z. B. Paleo soils and / or earlier generations of reliefs are required. When exploring these conditions, in addition to the study of outcrops and drill cores, geophysical methods such as z. B. seismics are used. The local and regional pattern of tectonic disturbances , any traditional igneous rocks, sedimentary rocks that may provide indications of the processing (i.e. the erosion and re-sedimentation) of rocks in the vicinity, as well as the general storage conditions of the rocks (generally lying or sloping ) allow conclusions to be drawn about geodynamic processes in the past. Fossils often only enable a relative temporal classification of sedimentary rocks and thus also the creation of an exact chronology of such processes. Further contain fossils and sedimentary rocks geochemical information (known as proxies ), which, among other things with the aid of CO 2 after obtaining content at that atmosphere or the paleo-sea temperature can be determined, whereby a sufficient amount of data to draw conclusions about the paleo air are possible . Radiometric dating makes it possible to prove at least the rock bodies suitable for this with an absolute age. The determination of the local paleomagnetic field in a certain rock, also a task of geophysics, enables the reconstruction of the geographical latitude on which a region was once located in the corresponding epoch.
Most of these data (and these are only selected examples) are not collected and evaluated at once and by a single researcher, but rather by many different geoscientists, often independently of one another, in the context of their specific research. Corresponding data often arise as a "by-product" of very contemporary, applied research, such as B. raw material exploration . Only later are the data, which are mostly published in scientific journals, combined into complex reconstructions of the paleo-environment. A particularly extensive reconstruction, which requires the evaluation of thousands of geo-archives, is z. B. a paleogeographic map of Europe or the world.
protection
The legal protection of scientifically particularly valuable complex geo-archives in the form of protected geotopes or even as world natural heritage serves to preserve them for future generations of geoscientists and interested laypeople.
See also
literature
- J. Eberle, B. Eitel, WD Blümel, P. Wittmann: Germany's south from the Middle Ages to the present. Heidelberg, 2007
- Dieter Kelletat: The coasts of the earth: diversity, geo-archives and risk areas. - A contribution to the 25th annual meeting of the working group “Geography of the Seas and Coasts”. In: G. Gönnert, B. Pflüger, J.-A. Bremer (Ed.): From geo-archeology to coastal dynamics to coastal zone management. Coastline Reports 9, 2007, pp. 1-14, ISSN 0928-2734 , ISBN 978-3-9811839-1-7
- Eduard Suess: The face of the earth. 3 volumes, 1883-1897 (as a historically outstanding German-language work on general geology)
- Ludwig Zöller, Ulrich Hambach, Henrik Blanchard, Stefanie Fischer, Sven Köhne, Rüdiger Stritzke: The Rodderberg crater near Bonn: A complex geographic archive . Quaternary Science Journal. 159 (1-2), 2010, pp. 44-58, doi : 10.3285 / eg.59.1-2.04
