Two areas of study, Sites 1076 and 1077, located in the Congo Basin, and Site 1081, situated on the Walvis Ridge, were selected to reconstruct climate change over the past 1.5 m.y. off the western coast of Africa. A multiproxy approach was adopted, involving the use of various analyses and techniques to generate several proxy records. A synthesis of the overall evolution of the two regions is provided in Figures F5 and F6. In particular, there is evidence for the influence of the MPR, yet, in addition, the records demonstrate that the continent and the ocean continued to respond to change following this event, both on long and short timescales.
Furthermore, the records from these two areas demonstrate that despite their close proximity, much of the variability in the records is localized. In particular, proxy productivity records at the Walvis Ridge show clear interglacial-glacial cyclicity with enhanced values occurring during glacial periods, assumed to be a response to enhanced upwelling and possibly intensification of the Benguela Current (Durham, 2000). Productivity in the Congo Basin is highly localized and, in fact, differs between the two sites, Holes 1076A and 1077A. These records show no clear glacial or interglacial cyclicity and instead are driven by a complex interaction of marine upwelling and influxes of nutrient-enriched waters from the Congo River.
In addition, the evidence from these records shows that there may not necessarily be a simple response to apparently simple or linear changes and that numerous factors may influence records from deep-sea sediments. It also demonstrates the complexity of the climate system, which responds on both long and short timescales, yet also appears to be dependent on the reaching of thresholds and the impacts of unpredicted and unpredictable events.