Modelling of Magmatic and Allied Processes


Book Description

Modeling of Magmatic and Allied Processes presents methods and models for the quantification of geological processes. Conceptual models for magmatic differentiation involving crystallization and mixing are presented and applied to field and textural data. Model equations for the degree of partial melting in presence perturbations of lithospheric geotherms and partitioning of trace/radioactive elements in the matrix and melts, and the formation of continents with melt additions are described. Diverse magmatic products are shown to result from differentiation processes rather than magmatic source heterogeneities. The degree of partial melting depends on mantle temperatures, for which parameterized thermal convection models are reviewed. Perturbations in geotherms caused by mantle heat flow, CO2 flux from great depths and tectonic thrusting are analyzed. The petrogenetic significance of accessory minerals of felsic magma evolution is assessed with the help of examples from Carpathian granitoids. Methods for simulating the 3-D Concentration and Distribution Models (DC-DMs) and fractal dimension of evolving magma systems are described with examples. The use of conventional scanning electron microscopy methods and electron microprobe to characterize and infer magmatic processes is explained, and the background and economic potential of hydrothermal systems are examined. The nature of oxidizing felsic magmas along with their potential for copper mineralization is discussed. In closing, the handling, calculation and plotting of geochemical data for igneous rock suites using the R-language-based software Geochemical Data Toolkit (GCDkit) along with plug-in modules for the forward and reverse mass-balance calculation of fractional crystallization are demonstrated.




Geochemical Modelling of Igneous Processes – Principles And Recipes in R Language


Book Description

The aim of this book is to unlock the power of the freeware R language to advanced university students and researchers dealing with whole-rock geochemistry of (meta-) igneous rocks. The first part covers data input/output, calculation of commonly used indexes and plotting in R. The core of the book then focusses on the presentation and practical implementations of modelling techniques used for fingerprinting processes such as partial melting, fractional crystallization, binary mixing or AFC using major-, trace-element and radiogenic isotope data. The reader will be given a firm theoretical basis for forward/reverse modelling, followed by exercises dealing with typical problems likely to be encountered in real life, and their solutions using R. The concluding sections demonstrate, using practical examples, how a researcher can proceed in developing a realistic model simulating natural systems. The appendices outline the fundamentals of the R language and provide a quick introduction to the open-source R-package GCDkit for interpretation of whole-rock geochemical data from igneous and metamorphic rocks.




Crustal Evolution of India and Antarctica


Book Description

The Proterozoic aeon involved at least three major continental readjustments. India and Antarctica appear in most models of supercontinent reconstructions, but their relative position has been the subject of debate. High-resolution petrological and geochronological data, especially from the Proterozoic mobile belts, provide the principal means of resolving this issue. The ice-covered nature of Antarctica allows only limited access to the rocks, and then only in coastal tracts, so detailed studies in more accessible Proterozoic terrains in India assume added significance. This volume, a follow-up to the XII International Symposium on Antarctic Earth Science, Goa (a SCAR symposium), provides new data from selected locations in east Antarctica (Enderby Land and Dronning Maud Land) and from India, including the Eastern Ghats Mobile Belt (EGMB), Chota Nagpur Gneissic Complex, the Khasi Hills and the Aravalli–Delhi Mobile Belt. The presented geochronological data, constrained by petrological studies, are expected to provide new insights, especially into the EGMB–east Antarctica connection and the rate of continental readjustments in the post-Rodinia break-up.




Dictionary of Mathematical Geosciences


Book Description

This dictionary includes a number of mathematical, statistical and computing terms and their definitions to assist geoscientists and provide guidance on the methods and terminology encountered in the literature. Each technical term used in the explanations can be found in the dictionary which also includes explanations of basics, such as trigonometric functions and logarithms. There are also citations from the relevant literature to show the term’s first use in mathematics, statistics, etc. and its subsequent usage in geosciences.




Post-Archean Granitic Rocks


Book Description

Granites (sensu lato) represent the dominant rock-type forming the upper–middle continental crust but their origin remains a matter of long-standing controversy. The granites may result from fractionation of mantle-derived basaltic magmas, or partial melting of different crustal protoliths at contrasting P–T conditions, either water-fluxed or fluid-absent. Consequently, many different mechanisms have been proposed to explain the compositional variability of granites ranging from whole igneous suites down to mineral scale. This book presents an overview of the state of the art, and envisages future avenues towards a better understanding of granite petrogenesis. Particular emphasis of this Volume is on the following topics: Compositional variability of granitic rocks generated in contrasting geodynamic settings during Proterozoic to Phanerozoic Periods, Main permissible mechanisms producing subduction-related granites, Crustal anatexis of different protoliths, and the role of water in granite petrogenesis, New theoretical and analytical tools available for modelling whole-rock geochemistry, in order to decipher the sources and evolution of granitic suites.







Large Igneous Provinces from Gondwana and Adjacent Regions


Book Description

Gondwana, comprising more than 64% of the present day continental mass, is home to 33% of large igneous provinces (LIPs) and key to understanding the lithosphere–atmosphere system and related tectonics that influenced global climate and sediment production on Earth. Gondwana has many of the largest LIPs, with areas of 200 000 to 2 000 000 km2. Several Gondwana LIPs erupted near active continental margins as well as within continents. The rifting of continents continued even after LIP emplacement or was aborted by a coeval compression and did not open into an ocean. Important contemporary frontiers include understanding significant amounts of synchronous silicic volcanic rocks in mafic LIPs, bringing better stratigraphic constraints supported by precise age dating and volume estimation of LIPs, the possible link between LIP emplacement and biotic crisis, refinement of the existing petrogenetic models and assessing large eruptions and associated societal risk. This volume covers topics on magma emplacements, petrology and geochemistry, source characteristics, flood basalt–carbonatite linkage, tectonics and geochronology of LIPs distributed in Gondwana continents.




Minerals and Allied Natural Resources and their Sustainable Development


Book Description

Nonrenewable natural resources – metallic and non-metallic minerals, industrial rocks and energy resources (both organic and inorganic), have been treated in a holistic manner in this book, including two important resources (soil and water), not commonly covered in most books on this topic. For the uninitiated reader, an introductory chapter looks into some basic definitions as well as nature and characteristics of mineral deposits followed by a chapter on the different crustal processes that produce the various ore deposits in the endogenous and exogenous environments. The strength of the book lies in its critical treatment of the genetic processes of the mineral deposits, their classification and the geodynamic context of metallogeny, and coverage of sustainable development of mineral deposits with special reference to various socio-economic as well as regulatory and environmental issues that face the Indian mining industry today. The text is punctuated with examples of Indian deposits, balanced with classical deposits around the world, to cater to the interests of Indian students and the international readership. This is a book for advanced undergraduate and post-graduate students of Geology, Environmental Sciences and Natural Resource Management.




Geology of the United States' Seafloor


Book Description

This book presents new, definitive studies of the seafloor adjacent to the United States.