This volume represents an edited selection of papers presented at the International symposium on the geology of tin deposits held in Nanning City in October 1984. It documents a great advance in our knowledge of tin deposits, particularly of the People's Republic of China. Details are presented in English for the first time on the major tin-polymetallic sulphide deposits of Dachang and Gejiu, which bear similarities to the deposits of Tasmania, but are little known to the geological community outside of China. The publication of this volume was sponsored by the United Nations ESCAP Regional Mineral Resources Development Centre (RMRDC), now a Regional Mineral Resources Development Project (RMRDP) within ESCAP. The Centre had previously published a report on the Symposium in Nanning City and the following field trip to the Dachang tin-polymetallic sulphide deposit of Guangxi, entitled "Report on the International Symposium on the Geology of Tin Deposits: Nanning and Dachang, China, 27 October - 8 November 1984". It is my privilege to acknowledge the help provided by Dr. J. F. McDivitt and Dr. H. W. Gebert, co-ordinator of ESCAP-RMRDC.

This volume represents an edited selection of papers presented at the International symposium on the geology of tin deposits held in Nanning City in October 1984. It documents a great advance in our knowledge of tin deposits, particularly of the People's Republic of China. Details are presented in English for the first time on the major tin-polymetallic sulphide deposits of Dachang and Gejiu, which bear similarities to the deposits of Tasmania, but are little known to the geological community outside of China. The publication of this volume was sponsored by the United Nations ESCAP Regional Mineral Resources Development Centre (RMRDC), now a Regional Mineral Resources Development Project (RMRDP) within ESCAP. The Centre had previously published a report on the Symposium in Nanning City and the following field trip to the Dachang tin-polymetallic sulphide deposit of Guangxi, entitled "Report on the International Symposium on the Geology of Tin Deposits: Nanning and Dachang, China, 27 October - 8 November 1984". It is my privilege to acknowledge the help provided by Dr. J. F. McDivitt and Dr. H. W. Gebert, co-ordinator of ESCAP-RMRDC.

This book is intended primarily for exploration geologists and post graduate students attending specialist courses in mineral exploration. Exploration geologists are engaged not only in the search for new mineral deposits, but also in the extension and re-assessment of existing ones. To succeed in these tasks, the exploration geologist is required to be a "generalist" of the Earth sciences rather than a specialist. The exploration geologist needs to be familiar with most aspects of the geology of ore deposits, and detailed knowledge as well as experience play an all important role in the successful exploration for mineral commodities. In order to achieve this, it is essential that the exploration geologist be up to date with the latest developments in the evolution of concepts and ideas in the Earth sciences. This is no easy task, as thousands of publications appear every year in an ever increasing number of journals, periodicals and books. For this reason it is also difficult, at times, to locate appropriate references on a particular mineral deposit type, although this problem is alleviated by the existence of large bibliographic data bases of geological records, abstracts and papers on computers. During my teaching to explorationists and, indeed, during my years of work as an explorationist, the necessity of having a text dealing with the fundamental aspects of hydrothermal mineral deposits has always been compelling. Metallic mineral deposits can be categorised into three great families, namely: (I) magmatic; (2) sedimentary and residual; (3) hydrothermal.

Fluid-aided mass transfer and subsequent mineral re-equilibration are the two defining features of metasomatism and must be present in order for metamorphism to occur. Coupled with igneous and tectonic processes, metasomatism has played a major role in the formation of the Earth’s continental and oceanic crust and lithospheric mantle as well as in their evolution and subsequent stabilization. Metasomatic processes can include ore mineralization, metasomatically induced alteration of oceanic lithosphere, mass transport in and alteration of subducted oceanic crust and overlying mantle wedge, which has subsequent implications regarding mass transport, fluid flow, and volatile storage in the lithospheric mantle overall, as well as both regional and localized crustal metamorphism. Metasomatic alteration of accessory minerals such as zircon or monazite can allow for the dating of metasomatic events as well as give additional information regarding the chemistry of the fluids responsible. Lastly present day movement of fluids in both the lithospheric mantle and deep to mid crust can be observed utilizing geophysical resources such as electrical resistivity and seismic data. Such observations help to further clarify the picture of actual metasomatic processes as inferred from basic petrographic, mineralogical, and geochemical data. The goal of this volume is to bring together a diverse group of geologists, each of whose specialities and long range experience regarding one or more aspects of metasomatism during geologic processes, should allow them to contribute to a series of review chapters, which outline the basis of our current understanding of how metasomatism influences and helps to control both the evolution and stability of the crust and lithospheric mantle.

Hydrothermal processes on Earth have played an important role in the evolution of our planet. These processes link the lithosphere, hydrosphere and biosphere in continuously evolving dynamic systems. Terrestrial hydrothermal processes have been active since water condensed to form the hydrosphere, most probably from about 4.4 Ga. The circulation of hot aqueous solution (hydrothermal systems) at, and below, the Earth’s surface is ultimately driven by magmatic heat. This book presents an in-depth review of hydrothermal proceses and systems that form beneath the oceans and in intracontinental rifts, continental margins and magmatic arcs. The interaction of hydrothermal fluids with rockwalls, the hydrophere and the biophere, together with changes in their composition through time and space, contribute to the formation of a wide range of mineral deposit types and associated wallrock alteration. On Earth, sites of hydrothermal activity support varied ecosystems based on a range of chemotrophic microorganisms both at surface and in the subsurface. This book also provides an overview of hydrothermal systems associated with meteorite impacts and explores the possibility that hydrothermal processes operate on other terrestrial planets, such as Mars, or satellites of the outer planets such as Titan and Europa. Possible analogues of extraterrestrial putative hydrothermal processes pose the intriguing question of whether primitive life, as we know it, may exist or existed in these planetary bodies. Audience: This volume will be of interest to scientists and researchers in geosciences and life sciences departments, as well as to professionals and scientists involved in mining and mineral exploration.