A model for the generation of intermediate and silicic igneous rocks is presented, based on experimental data and numerical modelling. The model is directed at subduction-related magmatism, but has general applicability to magmas generated in other plate tectonic settings, including continental rift zones. In the model mantlederived hydrous basalts emplaced as a succession of sills into the lower crust generate a deep crustal hot zone. Numerical modelling of the hot zone shows that melts are generated from two distinct sources; partial crystallization of basalt sills to produce residual H2O-rich melts; and partial melting of pre-existing crustal rocks. Incubation times between the injection of the first sill and generation of residual melts from basalt crystallization are controlled by the initial geotherm, the magma input rate and the emplacement depth. After this incubation period, the melt fraction and composition of residual melts are controlled by the temperature of the crust into which the basalt is intruded. Heat and H2O transfer from the crystallizing basalt promote partial melting of the surrounding crust, which can include meta-sedimentary and meta-igneous basement rocks and earlier basalt intrusions. Mixing of residual and crustal partial melts leads to diversity in isotope and trace element chemistry. Hot zone melts are H2O-rich. Consequently, they have low viscosity and density, and can readily detach from their source and ascend rapidly. In the case of adiabatic ascent the magma attains a super-liquidus state, because of the relative slopes of the adiabat and the liquidus. This leads to resorption of any entrained crystals or country rock xenoliths. Crystallization begins only when the ascending magma intersects its H2O-saturated liquidus at shallow depths. Decompression and degassing are the driving forces behind crystallization, which takes place at shallow depth on timescales of decades or less. Degassing and crystallization at shallow depth lead to large increases in viscosity and stalling of the magma to form volcano-feeding magma chambers and shallow plutons. It is proposed that chemical diversity in arc magmas is largely acquired in the lower crust, whereas textural diversity is related to shallow-level crystallization.

/pdf/the-genesis-of-intermediate-and-silicic-magmas-in-deep-3g95p0zv3p.pdf

The Genesis of Intermediate and Silicic Magmas in Deep Crustal Hot Zones

: This thesis applies neural network feature selection techniques to multivariate time series data to improve prediction of a target time series. Two approaches to feature selection are used. First, a subset enumeration method is used to determine which financial indicators are most useful for aiding in prediction of the S&P 500 futures daily price. The candidate indicators evaluated include RSI, Stochastics and several moving averages. Results indicate that the Stochastics and RSI indicators result in better prediction results than the moving averages. The second approach to feature selection is calculation of individual saliency metrics. A new decision boundary-based individual saliency metric, and a classifier independent saliency metric are developed and tested. Ruck's saliency metric, the decision boundary based saliency metric, and the classifier independent saliency metric are compared for a data set consisting of the RSI and Stochastics indicators as well as delayed closing price values. The decision based metric and the Ruck metric results are similar, but the classifier independent metric agrees with neither of the other metrics. The nine most salient features, determined by the decision boundary based metric, are used to train a neural network and the results are presented and compared to other published results. (AN)

/pdf/nonlinear-time-series-analysis-1j3a35n4y3.pdf

Nonlinear Time Series Analysis.

Journal of Physics Condensed Matter: Preface

A review of classical percolation theory is presented, with an emphasis on novel applications to statistical topography, turbulent diffusion, and heterogeneous media. Statistical topography involves the geometrical properties of the isosets (contour lines or surfaces) of a random potential $\ensuremath{\psi}(\mathrm{x})$. For rapidly decaying correlations of $\ensuremath{\psi}$, the isopotentials fall into the same universality class as the perimeters of percolation clusters. The topography of long-range correlated potentials involves many length scales and is associated either with the correlated percolation problem or with Mandelbrot's fractional Brownian reliefs. In all cases, the concept of fractal dimension is particularly fruitful in characterizing the geometry of random fields. The physical applications of statistical topography include diffusion in random velocity fields, heat and particle transport in turbulent plasmas, quantum Hall effect, magnetoresistance in inhomogeneous conductors with the classical Hall effect, and many others where random isopotentials are relevant. A geometrical approach to studying transport in random media, which captures essential qualitative features of the described phenomena, is advocated.

/pdf/percolation-statistical-topography-and-transport-in-random-1ddemlupey.pdf

Percolation, statistical topography, and transport in random media

r 9HE purpose of this paper is to explore a hypothesis, based on acIcumulating evidence, regarding the character of inventions likely to issue from the research laboratories of the large industrial corporations. Simply put, this hypothesis may be stated as follows: with few exceptions, the large industrial laboratories are likely to be minor sources of major (radically new and commercially or militarily important) inventions; rather they are likely to be major sources of essentially "improvement" inventions. Put more precisely, the hypothesis states that the proportion of all minor inventions originating in the large industrial laboratories is likely to exceed the proportion of all major inventions originating in these laboratories. Note that the stress on the relative importance of these laboratories as sources of improvement inventions is not necessarily a denigration of the economic importance of this contribution. The cumulative effect of these improvement inventions may be, and often has been, of substantial importance over long periods of time for advancing technology, investment opportunities, and economic growth. The stress on improvement inventions as the principal product of the research laboratories of the large industrial corporations is meant simply to emphasize that, whatever the importance of their contributions, most of the latter is not likely to involve radically new inventive activity. I cannot claim originality for this hypothesis. After it suggested itself in the course of my investigations, I discovered that others, some of them in the most unlikely positions,2 had earlier said much the same thing. But, apart from occasional remarks, I can find no discussions attempting to explain or justify it. And because, if reasonably accurate, it has numerous ramifications, I have felt the need to set down an extended analysis of 1 I wish to thank members of the Seminar on Law and Technology, sponsored by the University of Wisconsin Law School under the auspices of the Ford Foundation, for their many helpful comments on this paper. Especially do I wish to thank Professors Jacob Schmookler, Robert Merrill, John Stedman, Harrison White, and John Heath. 2 See particularly the statement quoted below (p. 114) of D)r. Frank Jewett, former president of Bell Laboratories.

The journal of political economy

Melt extraction and accumulation from partially molten rocks

On the KdV soliton formation and discrete spectral analysis

Statistical topography involves the study of the geometrical properties of the iso-sets (contour lines or surfaces) of a random potential ψ(r). Previous work [1,2] has addressed coastlines on a random relief ψ(x, y) that possess a single characteristic spatial scale λ with topography belonging to the universality class of the random percolation problem. In the present paper this previous analytical approach is extended to the case of a multiscale random function with a power spectrum of scales, ψλ ∝ λ
 H
 , in a wide range of wavelengths, λ0 < λ < λ
 m
 . It is found that the pattern of the coastline differs significantly from that of a monoscale landscape provided that −3/4 <H < 1, with the case −3/4 <H < 0 corresponding to the long-range correlated percolation and 0 <H < 1 to the fractional Brownian relief. The expression for the fractal dimension of an individual coastline is derived,D

 h
 = (10 − 3H)/7, the maximum value of whichD
h = 7/4, corresponds to the monoscale relief. The distribution functionF(a) of level lines over their sizea is calculated:F(a) ∝a
−4(1-H)/7, for λ0 ≪a ≪ λ
 m
 . A comparison of the theoretical results with geographical data is presented.

Jaan Kalda

Papers

Melt extraction and accumulation from partially molten rocks

On the KdV soliton formation and discrete spectral analysis

Statistical topography. I. Fractal dimension of coastlines and number-area rule for Islands

Statistical topography, II. Two-dimensional transport of a passive scalar

On the finite-time compressibility of the surface currents in the Gulf of Finland, the Baltic Sea