North Atlantic Ocean basin; Aspects of geologic structure and evolution
In creating Volume M, the Western North Atlantic region (Vogt and Tucholke, 1986a) for the Geology of North America series, we deemed it best from both oceanographic and plate-tectonic viewpoints to deal with the entire North Atlantic spreading system from the equator to the Arctic (Figs. 1 and 2), rather than limiting treatment to the western half of the ocean basin. Even so, the scope in some places had to be expanded. The Atlantic, like other ocean basins, did not evolve in isolation from global changes in tectonic regime, oceanic circulation, or climate patterns (Fig. 3). The development of plate-tectonic theory since the late 1960s clearly has emphasized the importance of these large-scale linkages.
The present chapter continues this philosophy, summarizing the geology of the North Atlantic but noting linkages to areas outside this ocean basin. The synthesis is based largely on material presented in Volume M. The citation or lack of citation of Volume Μ references here, however, reflects only the thematic fabric of the present synthesis, not the scientific merit of the chapters. We refer the reader to original sources in Volume Μ for more complete treatment. We begin this chapter by noting ties between Volume Μ and several other Geology of North America volumes, and we continue with some “vital statistics” that describe three basic components of the Atlantic in space and time: igneous crust, sediments, and ocean waters. This is followed by a discussion of scales of spatial and temporal variability, with emphasis on the latter. The chapter concludes with a summary of some of the important advances that have occurred in the three years since Volume Μ was published.