Figure 26. Close-up of crystalline basement map over north-central portion of Mauritanide belt (east-trending linear high of unknown origin) and younger dike anomalies (box 26, Fig. 17, Plates 1 and 2). A high amplitude east-trending magnetic high characterizes the northern end of the exposed Mauritanide chain (Fig. 26). The source of the anomaly is buried, but other east-trending anomalies seem also to be associated with the Mauritanide deformation of Archean BIF ((Meyer, Kolb et al. 2006). These anomalies are crossed by northerly trending highs associated with Jurassic dikes related to the opening of the Atlantic. Calculated depths to the top of magnetic basement (Fig. 11, Plate 1) range from ~200-700 m for the dikes and ~1500 m for the BIF source.
Figure 27. Close-up of crystalline basement map over the Coast Basin (box 27, Fig. 17, Plates 1 and 2).
