Line salt
As line salt a down to the micro range is visible alternating layers of different salts with clays or anhydrite designated. Line salts occur in many salt deposits around the world. Often the bending of the thin lines indicates the salt tectonic stress or mineral transformations during the diagenesis of the salt rocks. In the Germanic Basin , line salts are particularly widespread in the lower part of the Leine formation of the Zechstein group.
Training and composition
Line salts are characterized by alternating layers of different salts with clays, clayey anhydrites and anhydrites, millimeter to several centimeters thick. In general, the pitches are usually finer than the salt layers. Salt rocks with a coarser stratification are known as ribbon salts. Occasionally, deposits of more finely layered areas in ligament salts can also be observed and vice versa.
The thin salt layers are mostly formed by rock salt ( halite ), subordinate to potassium salt , such as carnallite , sylvine and kieserite as well as polyhalite . In mineralogical-geochemical investigations on salt rocks of the Gorleben salt dome , a percentage composition of the Leine line salt was determined with 94.4% halite, 5% anhydrite, 0.5% polyhalite and less than 0.1% carnallite.
In addition, Blödit , Löweit , Epsomit , Vanthoffit and Langbeinit have been detected in alpine salt deposits .
The salt between the clay or anhydrite lines is usually fine to medium, rarely coarsely crystalline. While the salts by evaporation ( evaporation ) in arid climates from a abgeschürten sea basin crystallized, the thin pitches on Staubeinwehungen are caused by surrounding solid countries.
Stratigraphic classification and occurrence
Line salts occur widely in different thicknesses and in different geological ages . In the Germanic Basin, line salts are particularly common in the Leine formation. Often they mark - in different stratigraphic positions - the diachronic transition from the Leine main anhydrite to the Leine rock salt. The line salt zone in the basin center of the Germanic Basin reaches the greatest thickness of over 50 m. In the direction of the surrounding mainland, for example in Thuringia , the foreland of the Harz Mountains and in the Hessian Basin , only facial equivalents of the line salt can be found, because here the sedimentation process was much more dominated by the mainland and the sea was partly already in the Leine period has withdrawn central parts of the pelvis, so that no more salts were excreted here (Leine rim facies). In the area of the Gorleben-Rambow salt structure, which has been intensively investigated geologically, 230 individual lines have been observed in the line salt zone.
Alpine Space Line salts from the Upper are Permian (270 to 251 million years ago), especially in the so-called Grüntongebirge of Hasel Mountains in space Berchtesgaden - Hallein to find.
Line salts are still formed in recent salt lakes .
literature
- Gerhard Richter-Bernburg: About saline sedimentation . Part IV. In: Journal of the German Geological Society . tape 105 , 1955, pp. 593-645 .
Individual evidence
- ^ Daniela Freyer: Geochemical boundary conditions for shaft closures for HAW repositories . In: TU Freiberg (ed.): ELSA workshop framework conditions for the design of manhole closures for repositories for high-level radioactive waste . Peine September 19, 2012, p. 5 ( tu-freiberg.de [PDF; 779 kB ; accessed on July 13, 2015]). tu-freiberg.de ( Memento of the original from July 13, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Otto Schauberger: On the genesis of the alpine Haselgebirge . In: Journal of the German Geological Society . tape 105 , 1955, pp. 736 .
- ^ A b Siegfried Keller: Long-term safety analysis for a HAW repository in salt. Geological reference model for a HAW repository site in salt . Ed .: Federal Institute for Geosciences and Raw Materials . Hanover 2007, p. 30th f .
- ^ Maria Schindl-Neumayer: Structural studies in alpine salt stores . In: Archive for deposit research of the Federal Geological Institute . tape 5 , 1984, ISSN 0253-097X , pp. 135-156 .
- ^ Rolf Langbein, Rolf Seidel: Zechstein . In: Gerd Seidel (Ed.): Geology of Thuringia . E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 1995, ISBN 3-510-65166-9 , p. 285-287 .
