the bulk of the world's phosphate reserves is located in sedimentary horizons that contain appreciable amounts of carbonate. during beneficiation of phosphate rocks, huge amounts of oversize phosphate rocks are rejected from crushers. this reject also mostly contains low tricalcium phosphate and high carbonate content. in this study, experiments have been carried out to reduce/eliminate carbona...

The formation of marine phosphatic mineral deposits remains incompletely understood, despite decades of research. The involvement of bacteria in this process has long been suspected, and both modern and ancient associations between bacteria and phosphorites have been recorded. Only recently has a specific bacterial metabolic process associated with the formation of phosphorites been discovered....

The bulk of the world's phosphate reserves is located in sedimentary horizons that contain appreciable amounts of carbonate. During beneficiation of phosphate rocks, huge amounts of oversize phosphate rocks are rejected from crushers. This reject also mostly contains low tricalcium phosphate and high carbonate content. In this study, experiments have been carried out to reduce/eliminate car...

This book is a collection of papers focusing on various aspects of authigenic and diagenetic marine minerals and related elemental cycling. In essence, it belongs to a line of specialized volumes marking major steps of continued international cooperation. Closely following the establishment of UNESCO International Geological Correlation Programme (IGCP) Project 156 (Phosphorites) in 1978, SEPM ...

The distribution of major phosphate deposits in the Precambrian sedimentary rock record is restricted to periods that witnessed global biogeochemical changes, but the cause of this distribution is unclear. The oldest known phosphogenic event occurred around 2.0 Ga and was followed, after more than 1.3 billion years, by an even larger phosphogenic event in the Neoproterozoic. Phosphorites (phosp...

Phosphatic sedimentary rocks preserve a record of early animal life different from and complementary to that provided by Ediacaran fossils in terminal Proterozoic sandstones and shales. Phosphorites of the Doushantuo Formation, South China, contain eggs, egg cases, and stereoblastulae that document animals of unspecified phylogenetic position; small fossils containing putative spicules may spec...

The Open University's repository of research publications and other research outputs Solar noble bases in enstatite chondrites and implications for the formation of the terrestrial planets Conference Item

Samples dredged from the Cruzeiro do Sul Lineament exhibit ferromanganese crusts precipitated above phosphate-rich substrates (phosphorites, phosphate-impregnated volcanic rocks and older phosphatized crusts). Co-chronology of crusts, paleontological data 87Sr/86Sr ratios substrate indicate that last phosphatization event in region happened between 17.6 14.6 Ma ago. When ceased, oxic conditions...

The Middle Mississippian Delle phosphatic event marks a significant change in depositional conditions in the Devonian–Mississippian Antler foreland basin of North America. Stratigraphic and petrographic studies show that deposition of Delle-event rocks ended a long period of open-marine carbonate sedimentation when facies shifted to phosphorites, cherts, fine-grained siliciclastics, and lime mu...