Banded Iron Formations to Iron Ore

Banded Iron Formations to Iron Ore

Author: Desmond Fitzgerald Lascelles

Publisher: Nova Science Publishers

Published: 2017-06

Total Pages: 0

ISBN-13: 9781536109719

DOWNLOAD EBOOK

From the first attempts to understand the origin of giant iron ore deposits, numerous false assumptions have been used as the basis of genesis models that have become standard and unquestioned, with later research generally seeking to find evidence supporting the existing models and ignoring contrary evidence. Many models were constructed based on extremely rare features, and their absence in the global abundance of iron formations was not considered important since there was no understanding of the major sedimentary structures, i.e. laminations and banding. Inconsistencies within the hypothetical models are either ignored or excused by proposing special circumstances, but no one considers that the models might be wrong or have only limited application. Many hypotheses regarding Earths history have been postulated from the difference between Phanerozoic and Precambrian iron-formations. In particular, the development of an oxygenated atmosphere has been deduced from the supposed evolution of iron-formations. The subject has provided a fertile field for research and models of Earths history, but without clear knowledge of the sedimentation, diagenesis and metamorphism of BIFs (branded iron formations), such models are speculative or even irrelevant. Since these models on the genesis and distribution of BIF were used as proxies to answer questions regarding the composition of the early oceans and atmosphere, weathering and transport conditions on early land surface, volcanism and continental development in the Archean eon, and as they affect exploration for the largest volume and most basic of industrial metals, they have an importance beyond academic sedimentary and stratigraphic interest. The aim of this book is to present a model for the origin of BIFs and derived high-grade iron ore deposits with global applications that are still subject to correction and change as new information becomes available and are free of illogical assumptions which do not conflict with either field observations or basic chemistry and physics.


Lake Pavin

Lake Pavin

Author: Télesphore Sime-Ngando

Publisher: Springer

Published: 2016-10-31

Total Pages: 422

ISBN-13: 3319399616

DOWNLOAD EBOOK

This book represents the first multidisciplinary scientific work on a deep volcanic maar lake in comparison with other similar temperate lakes. The syntheses of the main characteristics of Lake Pavin are, for the first time, set in a firmer footing comparative approach, encompassing regional, national, European and international aquatic science contexts. It is a unique lake because of its permanently anoxic monimolimnion, and furthermore, because of its small surface area, its substantially low human influence, and by the fact that it does not have a river inflow. The book reflects the scientific research done on the general limnology, history, origin, volcanology and geological environment as well as on the geochemistry and biogeochemical cycles. Other chapters focus on the biology and microbial ecology whereas the sedimentology and paleolimnology are also given attention. This volume will be of special interest to researchers and advanced students, primarily in the fields of limnology, biogeochemistry, and aquatic ecology.


The Archaean Geology of the Kaapvaal Craton, Southern Africa

The Archaean Geology of the Kaapvaal Craton, Southern Africa

Author: Alfred Kröner

Publisher: Springer

Published: 2019-02-20

Total Pages: 312

ISBN-13: 3319786520

DOWNLOAD EBOOK

This book provides a comprehensive overview of the evolution of one of the oldest and best-exposed Archaean cratons on this planet. There is currently a renewed interest in the early Earth, and the Kaapvaal craton has long served as a model for early crustal evolution. This unique multidisciplinary resource features information on geology, tectonics, geochemistry, and geochronology. It offers a wealth of new data on various aspects of the craton as well as contributions on the various crustal units by international specialists.


Evolution of Early Earth's Atmosphere, Hydrosphere, and Biosphere

Evolution of Early Earth's Atmosphere, Hydrosphere, and Biosphere

Author: Stephen E. Kesler

Publisher: Geological Society of America

Published: 2006-01-01

Total Pages: 350

ISBN-13: 0813711983

DOWNLOAD EBOOK

"The history of Earth's early atmosphere, hydrosphere, and biosphere, from Hadean through Proterozoic time, is one of geology's enduring puzzles. Ore deposits provide important insights into this history because they contain elements and minerals that are highly sensitive to the geochemical environment in which they form. Just what these minerals tell us remains a matter of considerable debate, however. When and how did life develop, an oxygen-rich atmosphere form, and sulfate dominate the ocean? This volume contains reports on these questions from both sides of the aisle for iron and manganese formations, uranium paleoplacers and hydrothermal deposits, and exhalative sulfides and oxides."--Publisher's website.


Iron Formations as Palaeoenvironmental Archives

Iron Formations as Palaeoenvironmental Archives

Author: Kaarel Mänd

Publisher: Cambridge University Press

Published: 2022-01-20

Total Pages: 66

ISBN-13: 1009002279

DOWNLOAD EBOOK

Ancient iron formations - iron and silica-rich chemical sedimentary rocks that formed throughout the Precambrian eons - provide a significant part of the evidence for the modern scientific understanding of palaeoenvironmental conditions in Archaean (4.0–2.5 billion years ago) and Proterozoic (2.5–0.539 billion years ago) times. Despite controversies regarding their formation mechanisms, iron formations are a testament to the influence of the Precambrian biosphere on early ocean chemistry. As many iron formations are pure chemical sediments that reflect the composition of the waters from which they precipitated, they can also serve as nuanced geochemical archives for the study of ancient marine temperatures, redox states, and elemental cycling, if proper care is taken to understand their sedimentological context.