Porcupine Basin displays - within the North Atlantic realm and perhaps in a global perspective - a unique association and diversity of carbonate mound provinces, which may yield the key to address the question of mound genesis and its significance in a global oceanic plot, from a processoriented point of view. The giant mounds on the present seabed surface southwest of Ireland, up to 200 m high, the extensive cluster of over a thousand buried reefs embedded in drift sediments, the whole range of mounds towering from a deeply ravinating unconformity on the eastern slope of Porcupine Basin are not mere curios, but significant build-ups, which may put Man on the track of hitherto unknown Biosphere processes thriving at the confluence of fluxes from both internal (geological) and external (oceanic) origin. In many aspects and mutatis mutandis, carbonate mounds might be for the Margins what sulphide mounds are on the Ridges: the product of biologically controlled geological processes, of global significance. The ‘Porcupine Drilling Project’ is driven by four major research projects funded under the 5th Framework Programme of the European Union (GEOMOUND, ECOMOUND, Deep-Bug and ACES) and hence it mobilizes a multi-disciplinary consortium of 22 institutes and research centres. A range of provoking hypotheses will be tested: the role of gas seeps as a prime trigger for mound genesis, the role of bacteria as main mound builders, the role of reef-forming corals as major part of the mound community and their environmental record potential, the significance of mound ‘events’ in a paleoenvironmental plot, the identification of prominent erosional surfaces as product of global oceanic turn-overs, the potential of mounds as high-resolution palaeoenvironmental recorders, the value of the Porcupine-Rockall mounds as present-day analogs for Phanerozoic reef mounds and carbonate mud mounds, and the potential role of fluid flow as common source of both slope failures and mound growth. Finally, a virtual link to biological processes is provided by the widespread existence of cold and deep-water coral and sponge reef ecosystems which colonize the flanks of the mounds. Preliminary results of the many site preparation cruises up to summer 2000 are presented and discussed. |
