Recent geological environments

There are various environments in which recent formation of Fe oxides on earth can be observed. Among these are active volcanoes, soils (see Chap. 16), rivers and lakes, oceans, both hydrothermal and cold springs, and biota (see Chap. 17). All these environments supply helpful information about the pathways of Fe oxide formation in the geological past of which they may be considered as present-day analogues. Since spectroscopic information about the red Martian surface became available, there has been much speculation about the possibility of past Fe oxide formation by surface weathering on Mars. 

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Kaplan 1. R. (1983) Stable isotopes of sulfur, nitrogen and deuterium in Recent marine environments. In Stable Isotopes in Sedimentary Geology, SEPM Short Course. Society for Sedimentary Research (SEPM), Tulsa, pp. 2-1-2-108. 

Much of the chemistry of the oceans and of freshwater systems depends on the kinetics of various physical and chemical processes and on biochemical reactions rather than on equilibrium conditions. The simplest model describing systems open to their environment is the time-invariant steady-state model. Because the sea has remained constant for the recent geological past, it may be well justified to interpret the ocean in terms of a steady-state model. 

Recent sediment. Solid unconsolidated organic and mineral material deposited in an aquatic environment during recent geologic time and which has undergone little geothermal evolution. 

Much of the contemporary discussion on Earth systems is focused on the relatively recent geological past and on the Earth s surface environments. This has tended to keep the discussion of Earth systems within only a few sub-disciplines of the Earth Sciences and away from traditional hard-rock geology. My goal, in this book, has been to show that if we consider the Earth on a long time scale, then Earth interactions involve all the major Earth reservoirs, including the solid Earth and the deep Earth. It has been my purpose here to draw attention to these interactions and to show that the solid Earth is an integral part of the Earth System which cannot be ignored, particularly in a discussion on the early Earth. Hence the focus of this book has been different from other Earth system science texts. 

Tessier et al. [82] pointed out the dependency between results and consistency of the sample, which is conditioned by the complexity of the microstructure of recent geological material. In this report we have already shown how complex conditions of both emergence and diagenesis of sediments affect the process in which various mineral phases can be found completely confined in other phases and hence become eco-chemically irrelevant, because they cannot participate in the processes of interaction with the surrounding (water) environment. This makes the above-mentioned model of Davies-Colley et al. [9] practically inappUcable, because it does not take into consideration this inactive phase. Here Ues one of the main causes of non-selectivity of sequential extraction - confined phases will be released only after their shell has been broken down (partially or completely) - therefore it is clear that in this manner a part of the carbonate, for example, can be found in the reducible phase , and a part of hydrous oxides in the organic phase , etc. 

There are two main approaches to such land disposal by burial either in near surface facilities for low and non heat generating medium level wastes or in deep imderground repositories in geological environments. Low and medium level wastes were disposed of in U countries in near surface facilities in France, United Kingdom and recently in Spain and in deep disposal facilities in Germany. 

The analysis of recent fatality investigations and accident statistics identified certain job categories, mining techniques, and geologic environments that appear to pose the greatest hazards. Best practices have been developed through experience and research to reduce these risks. They combine... 

The minerals of REs occur in various geological environments, and primary resource plays an exclusive role. The most representative primary resources are bastnasite, monazite, and ion-absorbed RE deposit. Bastnasite and monazite are the predominant minerals of light REs, while ion-absorbed RE deposit is the predominant mineral of heavy REs. Owing to their unique properties and recently strained supply, more countries were involved in the exploitation of REs. Then, a brief description of the present situation is as follows. 

The increased interest in Mo and W due to commodity price increases since 2006 has created a need for a synthesis of information on known deposits and potential exploration environments within the province of Newfoundland and Labrador. This review is drawn from the historical database of exploration and scientific studies, but it also provides some essential geological information concerning recent exploration developments in Newfoundland. Further information is provided in a recent article by Kerr et al. (2009). Molybdenum mineralization also occurs in Precambrian granites in Labrador, but these deposits presently lie within Inuit lands that are... 

In recent years, Raman spectroscopy has undergone a major transformation from a specialist laboratory technique to a practical analytical tool. This change was driven on several parallel fronts by dramatic advances in laser instrumentation, detectors, spectrometers, and optical filter technology. This resulted in the advent of a new generation of compact and robust Raman instruments with improved sensitivity and flexibility. These devices could be operated for the first time by non-specialists outside the laboratory environment. Indeed, Raman spectroscopy is now found in the chemical and pharmaceutical industries for process control and has very recently been introduced into hospitals. Handheld instruments are used in forensic and other security applications and battery-operated versions for field use are found in environmental and geological studies. 

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