Chapter 1 The Architecture and Structure of the Nigerian Continental Crust

Chapter 2 The Nigerian Migmatite‑Gneiss Complex: Product of Proterozoic Reworking of a Primitive Crust

Chapter 3 The Nigerian Iron Formations: Mineralogical Evolution, Geochemistry and Genesis

Chapter 4 Geometric and Kinematic Characterization of Fractures within the Basement Complex Rocks of Ago‑Iwoye, Southwestern Nigeria

This report summarizes the geology and nonfuel mineral resources of Greenland, Europe, Russia, and Northern Central Asia and is a preliminary part of a major U.S. Geological Survey study called the Global Mineral Resource Assessment Project. This report is one of a series of regional reports covering the world and provides basic data on the identified resources and geologic setting, together with a brief appraisal of the potential for undiscovered mineral resources. The data in the regional report are derived from published information. An important source of data on production statistics, economic factors that affect the mineral industries, and historical information, is available in U.S. Geological Survey (USGS) publications Minerals Yearbook and the annual Mineral Commodity Summaries (available at http://minerals.usgs.gov/minerals).

This report, which is one of a series of reports summarizing the World’s endowment of nonfuel mineral resources, describes the location and general geologic setting of deposits of major mineral commodities in the United States. The discussion in this report focuses on those commodities produced in the United States that constituted at least 5 percent of global production or global reserve base in 2003 or had at least $100 million production value in 2001. The discussion for each commodity begins with a brief description of the chemical and physical properties of the material and how it is used. The importance of the commodity in the United States relative to the world is also presented. However, most of the discussion emphasizes the geology of mineral commodities – the important mineral deposit types, their geologic setting, and the processes that led to their formation. A compilation of almost 400 major mineral deposits in the United States is included as an appendix. <...>

The Antarctic Ice Sheet has greatly affected global climate, sea level, ocean circulation, and southern hemisphere biota during Cenozoic times. Much of our understanding of the evolution of the ice sheet has been inferred from isotopic studies on distant deep-ocean sediments, because few Cenozoic rocks are exposed on the Antarctic continent. Yet, large differences occur between past ice volumes inferred from isotopic studies and those inferred from low-latitude sea-level variation.