caa a22 4500 477064108 CHVBK 20180405111407.0 cr unu---uuuuu 170330e19960301xx s 000 0 eng 10.1007/BF00192056 doi (NATIONALLICENCE)springer-10.1007/BF00192056 Morphological instabilities in pattern formation by precipitation and crystallization processes [Elektronische Daten] [H. Krug, H. Brandstädter, K. Jacob] Morphological instabilities in periodic patterns occurring both in precipitation and crystallization processes (Liesegang rings and crystal zoning) are investigated and compared with similar patterns in geological samples (zebra rocks and mud bands in snow sediments). In classical Liesegang systems, undisturbed parallel or concentric precipitation bands are emanated from even or concentric diffusion sources in homogeneous diffusion matrices of gelatine or other gels. In the case of superposing diffusion sources, sources with undulatory curvatures or local diffusion barriers there may occur several types of instabilities within the sequence of regular patterns: (a) gaps within the bands forming radial alleys free of precipitate, (b) transition from broken bands to speckled patterns and (c) apparent branching of bands linked together by so-called anastomoses. Calculations with a competitive particle growth (CPG) model show that lateral instabilities in Liesegang bands (gaps and radial alleys of gaps) are the result of Ostwald ripening effects taking place after precipitation. Apparent branching of bands or formation of anastomoses can be simulated with a prenucleation model according to Ostwald's supersaturation theory. Similar irregularities can be observed in zebra rocks (e.g. banded siderite) whose bandings are commonly explained by sequential sedimentation processes. A very different mechanism is assumed to be responsible for the origin of mud bands in snow sediments. An initially homogeneous distribution of intrinsic mud in snow sediments can be arranged into parallel bands according to a crystal zoning mechanism which is based on repeated thawing and freezing of the snow sediment due to the daily alternation of sun and darkness. Springer-Verlag, 1996 Anastomoses nationallicence Crystal zoning nationallicence Snow bands nationallicence Liesegang rings nationallicence Ostwald ripening nationallicence Self organization nationallicence Siderite nationallicence Supersaturation theory nationallicence Zebra rock nationallicence Krug H. Institut für Theoretische Physik, AG Dissipative Strukturen, Technische Universität Berlin, Geb. 2.14, Rudower Chaussee 5, D-12489, Berlin, Germany aut Brandstädter H. Institut für Theoretische Physik, AG Dissipative Strukturen, Technische Universität Berlin, Geb. 2.14, Rudower Chaussee 5, D-12489, Berlin, Germany aut Jacob K. Institut für Angewandte Geophysik, Petrologie und Lagerstättenforschung, Technische Universität Berlin, Ernst-Reuter-Platz 1, Sekr. BH 4, D-10587, Berlin, Germany aut Geologische Rundschau Springer-Verlag 85/1(1996-03-01), 19-28 0016-7835 85:1<19 1996 85 531 https://doi.org/10.1007/BF00192056 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00192056 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Krug H. Institut für Theoretische Physik, AG Dissipative Strukturen, Technische Universität Berlin, Geb. 2.14, Rudower Chaussee 5, D-12489, Berlin, Germany aut NATIONALLICENCE 700 1- Brandstädter H. Institut für Theoretische Physik, AG Dissipative Strukturen, Technische Universität Berlin, Geb. 2.14, Rudower Chaussee 5, D-12489, Berlin, Germany aut NATIONALLICENCE 700 1- Jacob K. Institut für Angewandte Geophysik, Petrologie und Lagerstättenforschung, Technische Universität Berlin, Ernst-Reuter-Platz 1, Sekr. BH 4, D-10587, Berlin, Germany aut NATIONALLICENCE 773 0- Geologische Rundschau Springer-Verlag 85/1(1996-03-01), 19-28 0016-7835 85:1<19 1996 85 531 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer