|LC Classifications||QE461 .R593 1990|
|The Physical Object|
|Pagination||viii, 285 p. :|
|Number of Pages||285|
|LC Control Number||90-36012|
About this book Following their recognition by GUmbel (), lamprophyres were treated for an entire century as little more than obscure curiosities. Because not even a world map of known lamprophyres was previously available, almost half the book is deliberately taken up by the first global lamprophyre compilation, . Discussing the distribution, occurrence and types of a group of alkali-rich igneous rocks called lamprophyres, this book examines their growing importance in economic geology. This study should be of interest to both professionals and students of petrology, geology and economic geology. Following their recognition by Gumbel (), lamprophyres were treated for an entire century as little more than obscure curiosities.
This book provides a comprehensive overview of lamprophyres, and discusses the distribution, occurrence and types of lamprophyre, together with associated rock types and their growing importance in economic geology. Lamprophyre Lamprophyre dating was discussed in Chapter 5, and Rock's statement that wherever detailed field and/or geochronological evidence is available, lamprophyres overlap gold mineralization in both time and space satisfies our syngenetic criteria. From: The Metallogeny of Lode Gold Deposits, lamprophyres: carbonates are also found as pseudomorphs after olivine, melilite or other minerals, as intergrowths with talc, garnet, etc., and as late veins (Rock, ). Rock () classiﬁes primary and secondary carbonates based on stable isotopic composition of lamprophyres from . 1. Introduction. Lamprophyres are mafic to ultramafic, porphyritic, volatile-rich hypabyssal igneous rocks with abundant melanocratic phenocrysts (Rock and Groves, a, Rock and Groves, b), and it is widely accepted that lamprophyres are generated by small degrees of melting of the metasomatized lithospheric mantle (Deng et al., , Li et al., , Pandey et al., , Yang et al., .
IOS Press Ebooks - Metallogeny and Petrogenesis of Lamprophyres in the Mid-European Variscides - Post-Collisional Magmatism and Its Relationship to Late-Variscan Ore Forming Processes in the Erzgebirge (Bohemian Massif) Ebook: Metallogeny and Petrogenesis of Lamprophyres in the Mid-European Variscides. Many lamprophyres contain ocelli, small spheroidal bodies consisting of alkali-rich feldspar, analcime, or calcite with minor femic minerals. The content above is only an . Petrographically, lamprophyres are set apart from most other igneous rocks by the presence of mafics, by the lack of feldspar phenocrysts, and by the abundance of mafics combined with alkali-rich feldspar. Chemically, the lamprophyres are unique because of their low silica content and a high iron, magnesium, and alkali content. Lamprophyres are uncommon, small volume ultrapotassic igneous rocks primarily occurring as dikes, lopoliths, laccoliths, stocks and small intrusions. They are alkaline silica-undersaturated, ultramafic rocks with high magnesium oxide, >3% potassium oxide, high sodium oxide and high nickel and chromium.