Phosphate Deposits Of The World Volume 3 Neogene To Modern Phosphorites

The origin of marine phosphorites, the principal raw material for phosphatic fertilizers, appears to be related mainly to marine biological productivity, often associated with upwelling currents during certain intervals of geological time. This book examines the environmental setting and resulting phosphorites which formed during the Miocene period, and investigations of modern oceanic environments where phosphorites are presently forming are also described.

This book is an important contribution to the scientific understanding of phosphate deposits.

The book presents a new and comprehensive model for the development of phosphate sediments. Starting with geochemistry and including new methods in sedimentology (sequence stratigraphy), it results in an interdisciplinary approach to a resource system covering all fields of phosphate geology. For researchers, teachers and students alike the book offers a complete overview of the whole field including case studies of major deposits.

This Proceedings volume contains 14 papers from the symposium ''Siliceous, Phosphatic and Glauconitic Sediments of the Tertiary and Mesozoic'', which was held during the 29th International Geological Congress, Kyoto, Japan, 24 August--3 September, 1992. The first part of this volume consists of papers dealing with Tertiary biosiliceous sediments of the Pacific Rim, starting in the northwest. The second part of the volume is composed of papers dealing with Tertiary and Mesozoic phosphatic rocks and phosphatebearing sequences, in particular of the eastern Pacific Rim and the Middle East. The articles serve to emphasize the similarities and differences between the Pacific Neogene successions and the Tethyan Mesozoic sequences of the Middle East.

This extensively updated new edition of the widely acclaimed Treatise on Geochemistry has increased its coverage beyond the wide range of geochemical subject areas in the first edition, with five new volumes which include: the history of the atmosphere, geochemistry of mineral deposits, archaeology and anthropology, organic geochemistry and analytical geochemistry. In addition, the original Volume 1 on "Meteorites, Comets, and Planets" was expanded into two separate volumes dealing with meteorites and planets, respectively. These additions increased the number of volumes in the Treatise from 9 to 15 with the index/appendices volume remaining as the last volume (Volume 16). Each of the original volumes was scrutinized by the appropriate volume editors, with respect to necessary revisions as well as additions and deletions. As a result, 27% were republished without major changes, 66% were revised and 126 new chapters were added. In a many-faceted field such as Geochemistry, explaining and understanding how one sub-field relates to another is key. Instructors will find the complete overviews with extensive cross-referencing useful additions to their course packs and students will benefit from the contextual organization of the subject matter Six new volumes added and 66% updated from 1st edition. The Editors of this work have taken every measure to include the many suggestions received from readers and ensure comprehensiveness of coverage and added value in this 2nd edition The esteemed Board of Volume Editors and Editors-in-Chief worked cohesively to ensure a uniform and consistent approach to the content, which is an amazing accomplishment for a 15-volume work (16 volumes including index volume)!

Phosphatic concretions occur within diatomite in the upper part of the Miocene Monterey Formation near Lompoc, Calif. Absence of disruption of fine laminar bedding in the associated sediment by the concretions shows that they formed after complete compaction of the enclosing sediment.The concretions exhibit a strongly concentric color, chemical, and mineralogic zonation. Many of them are composed of a nucleus in which vivianite is the dominant mineral. Amorphous ferric phosphate, mitridatite, and francolite are the dominant phosphatic phases in successive layers toward the surface of the concretions. Cd and As contents increase tenfold from the nucleus outward, reaching a maximum of 2,000 ppm, whereas Ni content, with a maximum of 720 ppm, and Co content show the opposite trend. This mineralogy and elemental composition favor accretion under conditions of continuously increasing Eh and pH, during uplift into the fresh-ground-water zone of the terrestrial environment. Shale-normalized rare-earth-element patterns, however, suggest a marine source for the elements biogenic debris consisting of opal-A, organic matter, and carbonates of the enclosing sediment.