476
10 SEDIMENTARY BASINS
Fig. 10.8. (A, B) Atlantic and Gondwana continental reconstructions showing the distribution of PreCambrian banded ironstone formations. (C) Global reconstruction of the Pre-Cambrian continent, Pangea,
showing how the banded ironstone deposits have a curvilinear distribution. (From Goodwin, 1973. Courtesy
of Academic Press.)
was drawn up. As with most geological phenomena, basins can be broadly grouped into
several fairly well-established families, whose limits are ill-defined. The attempt at basin classification given in Table 10.1 owes much to those already cited. This scheme will
be used as a framework for the following description and discussion of sedimentary basins. Figure 10.11 shows how the major types of sedimentary basin can be related to
plate tectonic setting.
10.2.2 Crustal Sag Basins
A sedimentary basin, in the restricted sense of the term, is an essentially saucer-shaped
area of sedimentary rocks. It is, therefore, subrounded in plan view. Strata dip and
thicken centripetally toward the center of the basin. It is an interesting exercise, however, to draw a cross-section of a basin to scale, allowing for the curvature of the earth.
10 SEDIMENTARY BASINS
Fig. 10.8. (A, B) Atlantic and Gondwana continental reconstructions showing the distribution of PreCambrian banded ironstone formations. (C) Global reconstruction of the Pre-Cambrian continent, Pangea,
showing how the banded ironstone deposits have a curvilinear distribution. (From Goodwin, 1973. Courtesy
of Academic Press.)
was drawn up. As with most geological phenomena, basins can be broadly grouped into
several fairly well-established families, whose limits are ill-defined. The attempt at basin classification given in Table 10.1 owes much to those already cited. This scheme will
be used as a framework for the following description and discussion of sedimentary basins. Figure 10.11 shows how the major types of sedimentary basin can be related to
plate tectonic setting.
10.2.2 Crustal Sag Basins
A sedimentary basin, in the restricted sense of the term, is an essentially saucer-shaped
area of sedimentary rocks. It is, therefore, subrounded in plan view. Strata dip and
thicken centripetally toward the center of the basin. It is an interesting exercise, however, to draw a cross-section of a basin to scale, allowing for the curvature of the earth.