In 1930 Bruno Sander, in his now classic Gefiigekunde der Gesteine, presented a comprehensive account of the fabric of deformed rocks, new geometric methods for its analysis, and a broad philosophy for its kine¬ matic interpretation. Since then, and especially since the Second World War, Sander’s methods have been applied with varying degrees of success in attempts to elucidate the structure of metamorphic rocks in many countries. Outstandingly successful among such attempts are studies, still in progress, on the nature and geometry of repeated folding in the Highlands of Scotland.

The mechanism of continental growth of Central Asia is currently debated between models invoking continuous subduction–accretion, or punctuated accretion due to closure of multiple ocean basins. Ophiolites in Central Asia may represent offscraped fragments in an accretionary complex or true collisional sutures. The Bayankhongor ophiolite, a NW–SE-striking sublinear belt 300 km long and 20 km wide, is the largest ophiolite in Mongolia and possibly Central Asia. We present results of the first detailed structural and lithological study of the ophiolite. The study area is divided into four zones: Baidrag complex, Burd Gol, Bayankhongor, and Dzag zones. The Archaean Baidrag complex comprises tonalitic granulites and metasediments. The Burd Gol zone is a metamorphosed sedimentary and igneous me´lange. The Bayankhongor zone contains the dismembered ophiolite forming a serpentinite me´lange. The Dzag zone consists of asymmetrically folded chlorite–mica schists resembling meta-turbidites. The structure is dominated by steeply dipping, NE directed thrusts and NE-vergent folds. We suggest the Bayankhongor ophiolite marks the closure of an ocean separating two microcontinents: the Baidrag complex with the Burd Gol accretionary complex to the south, and a northern continent that forms the basement for the Hangai region. Subduction was towards the SW with NE-directed ophiolite obduction onto a passive margin represented by the Dzag zone.

PLAN:

1. INTRODUCTION

2. OBJECTIVES

3. HISTORY AND PREVIOUS WORK

4. METHODS

5. GEOLOGY AT DEEP POST MINE

6. Stratigraphy

7. Structures

8. HYDROTHERMAL ALTERATION

9. MINERALIZATION

10. MODEL AND CONCLUSIONS

This book is a collection of reviews concerning the structural and coordination chemistry of actinide compounds. Over the past decade, these compounds have attracted considerable attention because of their importance for radioactive waste management, catalysis, ion-exchange and absorption applications, and various other applications. Synthetic and natural actinide compounds form as a result of alteration of spent nuclear fuel and radioactive waste under Earth surface conditions, during burn-up of nuclear fuel in reactors, and as oxidation products of uranium mines and mine tailings. Soils and sediments contaminated by actinides often contain such phases as well. Actinide compounds are also of considerable interest to materials scientists owing to the unique electronic properties of actinides which give rise to interesting physical properties that are controlled by the structural architecture of the respective compounds. <...>