When I first started conducting research in Mongolia, I found that I could make a room full of anthropologists jealous by telling them where I worked. To a discipline whose members pride themselves on working in exotic locations, Mongolia is a glamorous research site, for few Western and even fewer American anthropologists had worked there during the Cold War.1 Young anthropologists started to trickle in during the early 1990s: Norwegian, Danish, and French graduate students; Christopher Kaplonski, Peter Marsh, and Katherine Petrie from the United States; and, of course, the University of Cambridge research group (Mongolian and Inner Asian Studies Unit) headed by Caroline Humphrey and now David Sneath. So anthropology, my discipline, was becoming interested in Mongolia.

Located approximately 400 km south of Lima, Peru, the Marcona and Pampa de Pongo deposits are the largest iron accumulations with associated copper and gold along the western coast of South America. Approximate resources include more than 1400 Mt of iron ore at Marcona and 1000 Mt of magnetite mineralisation at Pampa de Pongo. Both deposits contain some copper and gold and exhibit numerous features that allow their inclusion in the "Iron Oxide-Copper-Gold" clan of deposits, alongside such examples asCandelaria and Mantos Blancos in Chile. The two deposits form part of a cluster of similar occurrences that together define the "Marcona Fe-Cu District".

All symbols used in the present work are defined at the appropriate place in the text, which can be found by reference to the index at the end of the volume. The units defined below, and the symbols by which they are identified, are confined to a general list of those most commonly used in the present work; other units will be defined where necessary in the text itself. It must be noted that a number of traditional units have been retained as a matter of policy throughout the work because they are still widely used in the current as well as in the past literature; e.g. the litre has been used as a unit volume although IAPSO have recommended that for high-precision measurements of volume it be replaced by the cubic decimetre (dm3). For a detailed treatment of the use of SI units in oceanography see the IAPSO recommendations published by Unesco (1985). <...>

The fundamental question underlying marine geochemistry is 'How do the oceans work as a chemical system?' At present, that question cannot be fully answered. However, the past two decades or so have seen a number of 'quantum leaps' in our understanding of some aspects of marine geochemistry. Three principal factors have made these leaps possible: (a) advances in sampling and analytical techniques; (b) the development of theoretical concepts; and (c) the setting up of large-scale international oceanographic programmes (e.g. DSDP, MANOP, HEBBLE, GEOSECS, TTO, VERTEX, GOFS, SEAREX), which have extended the marine geochemistry database to a global ocean scale. <...>