Pattern formation geochemical

Beckner J. R. and Mozley P. S. (1998) Origin and spatial distribution of early vadose and phreatic calcite cements in the Zia Formation, Albuquerque Basin, New Mexico, USA. In Carbonate Cementation in Sandstones. Distribution Patterns and Geochemical Evolution (ed. S. Morad). International Association of Sedimentologists, Oxford, vol. 26, pp. 27-52. 

Non-equilibrium thermodynamics (de Groot and Mazur, 1984 Prigogine, 1977) affords an abstract, and therefore very general, foundation for understanding pattern formation. The abstract nature of this approach makes direct application to geochemical problems difficult, but non-equilibrium thermodynamics does provide a powerful conceptual basis for thinking about pattern formation. 

MODELING NONLINEAR WAVE PROPAGATION AND PATTERN FORMATION AT GEOCHEMICAL FIRST ORDER PHASE TRANSITIONS... 

The many beautiful examples of geochemical pattern formation presented by E. Merino (see these proceedings) underscore the breadth of phenomena in these systems and the interest in modeling them. Here we shall discuss the mathematical modeling of some of these phenomena and, in addition, the modeling of a number of nonlinear reaction-transport waves in porous media flow-reaction problems. All these phenomena have the common feature that they arise out of the coupling of the kinetics of first order phase transitions to transport. Interest in these phenomena is not new but dates past the beginning of this century - see [1] and [2] for early citations. 

Despite the individual features of formation of the deposits and differences in ore composition and morphology, a general pattern of distribution of elements of the siderophiie group can be observed. They accumulate in the peripheral areas of ore objects (the nuclear parts of ore geochemical systems) of different categories, often forming a picture of concentric zonality. 

The next subchapter is to show how formation of would-be bioligands during chemical evolution and changes of limiting geochemical conditions interacted to bind some basic set of going-to-be-essential elements to biomass, with the patterns of essential elements... 

These characteristics pose a set of rather difficult problems in describing the genesis of the Formation. A geochemical postulate has been developed (4) to explain this genesis and its peculiarities. This pattern is outlined. 

Bidoclio, G., a. Avooadro, A. De Plano, and G. P Laz-ZARi. 1984. Geochemical pattern of americium in the saline area surrounding a rock salt formation. Radioactive Waste Management and the Nuclear Fuel Cycle 5(4) 311-326. 

The aims this study are to elucidate the factors controlling the distribution pattern, mineralogy and geochemical composition of calcite and dolomite cements, and of grain dissolution and kaolin-ization in the fluvial sandstones of the Serraria Formation, northeastern Brazil (Fig. 1). This unit provides an excellent opportunity to examine the influence of variations in the palaeogeographical setting, palaeoclimate and burial history on diagenetic processes. 

Chemical precipitation is one of the easiest things to see in past history, because it forms solid puddles of rock. At this point in our story, 2-3 billion years ago, an unusual set of precipitates rained down as red jasper and other iron-oxide rocks, laid down as neat red layers alternating with gray silica. These banded iron formations (B1 Fs) are evidence of a planet-wide geochemical shift. Complementary methods like uranium isotope patterns back up this story. 

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