Mineralization in intracratonic basins
An oceanic spreading axis like the Mid-Atlantic Ridge, began life as an intracratonic rift, when the Americas were a continuous part of Laurasia or Gondwanaland. Sea-floor spreading along the major rift system led to the progressive westwards drift of the Americas. The Benue Trough of Nigeria—Cameroons, however, failed to achieve complete separation and ended up as a failed arm or aulacogen (Figure 12.5). Intracratonic spreading axes are closely similar to mid-ocean ridges but there are obvious differences because of the proximity of continental land masses. For one thing, they are easier to locate and study than the mid-ocean ridges because the geothermal field associated with the spreading is not dissipated by great volumes of oceanic water. Not all intracratonic basins develop truly oceanic characteristics.
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