Sediment-hosted Pb-Zn (Cu-Ba) Mineralisation Within the Coastal Branches of the Damara Orogen, Namibia


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Die vorliegende Studie ist Ergebnis einer in Namibia und Deutschland durchgeführten Literaturrecherche zu sedimentgebundenen Blei-Zink- (Kupfer-Barium)-Vorkommen in den Pan-Afrikanischen Kaoko- und Gariep- Faltengürteln der nördlichen und südlichen Küstenregion Namibias. Die Literaturstudie zeigt, dass metallogenetische Untersuchungen der Buntmetallmineralisationen in diesen orogenen Gürteln Namibias einen aktuellen Forschungsschwerpunkt darstellen. Begründet liegt dies unter anderem in den vergleichsweise begrenzten, derzeit bekannten Rohstoffvorräten an Zink, Blei,Baryt, Silber und Kupfer, die zukünftig einen erhöhten Innovationsbedarf haben und somit verstärkte Explorationsanstrengungen erfordern. Dies wird auch deutlich durch die defizitäre Bilanz aus Zinkproduktion und -nachfrage von 1994 bis 1999 der westlichen Welt. Insbesondere seit den neunziger Jahren wurden in Namibia verstärkt Explorationsinvestitionen durch internationale Explorations- und Bergbaufirmen getätigt. Das Land verfügt über eine lange und erfolgreiche Bergbautradition, deren Wurzeln in einer relativ stabilen politischen Situation, exzellenter Infrastruktur, einem modernen Bergrecht und hochwertigen, gut zugänglichen geologischen und geophysikalischen Daten begründet liegen. - Schlieilich bietet sich die Anwendung der Ga/Ge-Geothermometrie von Sphalerit an und diese sollte in verschiedenen Erzparagenesen der Rosh Pinah Lagerstätte getestet werden. Hierbei verspricht ein kritischer Vergleich der geochemisch ermittelten TGa/Ge mit der mikrothermometrisch bestimmten TF.I. und vor allem der Gebrauch des Verhältnisses TGa/Ge / TF.I. als Proximitätsindikator auch einen positiven Beitrag zur metallogenetischen Grundlagenforschung.




Geology of Southwest Gondwana


Book Description

This book focuses on the geological evolution of Southwest (SW) Gondwana and presents state-of-the-art insights into its evolution. It addresses the diachronic assembly of continental fragments derived from the break-up of the Rodinia supercontinent later amalgamated to build SW Gondwana during the Neoproterozoic–Cambrian transition, which on a global scale includes parts of present-day South America, Africa and Madagascar. The book presents 24 state-of-the-art reviews including the most crucial controversies. Most experienced scientists about the geology of SW Gondwana from Europe, Africa, South America and Australia present contributions on key areas addressing the interactions between the main cratons and fold belts on both sides of the South Atlantic Ocean. Chapters related to the geology of the major Archean- Paleoproterozoic cratons and Neoproterozoic Brasiliano/Pan-African fold belts enable readers to gain an in-depth understanding of the tectonometamorphic and magmatic evolution of SW Gondwana. The book covers a wide range of issues including metallogenetic, sedimentary, paleobiological and paleoclimatic processes and allows a deep insight into this key period of the Earth’s evolution.







Africa


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Information Circular


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Critical Mineral Resources of the United States


Book Description

As the importance and dependence of specific mineral commodities increase, so does concern about their supply. The United States is currently 100 percent reliant on foreign sources for 20 mineral commodities and imports the majority of its supply of more than 50 mineral commodities. Mineral commodities that have important uses and face potential supply disruption are critical to American economic and national security. However, a mineral commodity's importance and the nature of its supply chain can change with time; a mineral commodity that may not have been considered critical 25 years ago may be critical today, and one considered critical today may not be so in the future. The U.S. Geological Survey has produced this volume to describe a select group of mineral commodities currently critical to our economy and security. For each mineral commodity covered, the authors provide a comprehensive look at (1) the commodity's use; (2) the geology and global distribution of the mineral deposit types that account for the present and possible future supply of the commodity; (3) the current status of production, reserves, and resources in the United States and globally; and (4) environmental considerations related to the commodity's production from different types of mineral deposits. The volume describes U.S. critical mineral resources in a global context, for no country can be self-sufficient for all its mineral commodity needs, and the United States will always rely on global mineral commodity supply chains. This volume provides the scientific understanding of critical mineral resources required for informed decisionmaking by those responsible for ensuring that the United States has a secure and sustainable supply of mineral commodities.




Understanding Mineral Deposits


Book Description

Mineral deposits have supplied useful or valuable material for human consumption long before they became objects of scientific curiosity or commercial exploitation. In fact, the earliest human interest in rocks was probably because of the easily accessible, useful (e. g. , red pigment in the form of earthy hematite) or valuable (e. g. , native gold and gemstones) materials they contained at places. In modem times, the study of mineral deposits has evolved into an applied science employing detailed field observations, sophisticated laboratory techniques for additional information, and computer modeling to build complex hypotheses. Understanding concepts that would someday help geologists to find new mineral deposits or exploit the known ones more efficiently have always been, and will continue to be, at the core of any course on mineral deposits, but it is a fascinating subject in its own right, even for students who do not intend to be professional economic geologists. I believe that a course on mineral deposits should be designed as a "capstone course" that illustrates a comprehensive application of concepts from many other disciplines in geology (mineralogy, stratigraphy and sedimentation, structure and tectonics, petrology, geochemistry, paleontology, geomorphology, etc. ). This book is intended as a text for such an introductory course in economic geology, primarily for senior undergraduate and graduate students in colleges and universities. It should also serve as a useful information resource for professional economic geologists.