Nature and Significance of the Recent Carbonate Mound Record: The Mound Challenger Code (Lecture Notes in Earth Sciences Book 126)

The discovery of recent carbonate mounds and cold-water coral reefs along the European continental margins is a major achievement of the past decade. Different research projects have been developed, fueling vivid debates. The objectives of this study, which rides the wave of recent carbonate mound and cold-water coral research, are twofold: (1) to elucidate for the first time in history the nature and internal structure of a whole carbonate mound body, from base to top, and (2) to discuss the significance of the recent carbonate mound record. Challenger Mound, localized in Porcupine Seabight SW of Ireland, has been drilled during IODP Expedition Leg 307 "Modern Carbonate Mounds: Porcupine Drilling". The obtained mound record is compared with other mound structures in Porcupine Seabight and with a cluster of mounds in the Gulf of Cadiz, along the Moroccan margin. In this way, the authors highlight that recent carbonate mounds form a specific and important category within the wide range of diverse deep-water carbonate systems. Carbonate mounds are an important feature along the European North-Atlantic margins. The presence of giant carbonate mounds in the Porcupine Seabight, on the Porcupine Bank, in the Rockall Trough and on the Rockall Bank, west of Ireland, have been known since the nineties and have been the target of several cruises during the last decade. However, the processes of mound build-up and mound nucleation are not yet completely understood. What keeps a mound growing over extended time periods? How does the biosphere interact with sedimentary fluxes to make a mound grow? On which level do palaeoclimatological and palaeoceanographic changes control mound growth? Which diagenetic processes play an important role in carbonate mound generation and how do they affect the mound? The present study focuses on the nature and significance of the carbonate mound record, and the nature and internal structure of one specific carbonate mound, the Challenger Mound, is described in detail and compared with other mounds from the Irish margin and also with those from the Moroccan margin. The variety of mound characteristics are discussed, along with the associated oceanographic and geological settings and an appropriate classification for recent carbonate mound systems and cold-water coral reefs is presented. Video imagery through Remotely Operated Vehicle (ROV) surveys, provide images of the surface of different carbonate mounds to highlight morphological characteristics of the mounds. The role of recent carbonate mounds, such as Challenger Mound, in the global carbonate budget is discussed along with inferences on how recent carbonate mounds can be seen as analogues of ancient mud mound systems. No books are available on the market describing recent carbonate mounds along the European continental margins and deciphering step by step their internal structure. The first results of IODP Expedition 307 "Modern Carbonate Mounds: Porcupine Drilling" are published in Ferdelman, T.G., Kano, A., Williams, T., Henriet, J.-P., and the Expedition 307 Scientists, 2006. Proc. IODP, 307: Washington, DC (Integrated Ocean Drilling Program Management International, Inc.). doi:10.2204/iodp.proc.307.2006. However, these proceedings do not give an overview of the existing knowledge on carbonate mounds and do not include detailed post-cruise analysis and advanced interpretations. Front Matter....Pages i-xx Of Mounds and Cold-Water Corals....Pages 1-12 Challenger Mound: A Case Study....Pages 13-44 Imaging....Pages 45-77 Geophysical and Geochemical Core Logging....Pages 79-119 Magnetic Record of a Carbonate Mound....Pages 121-166 The Top of the Record: On-Mound and Off-Mound....Pages 167-191 Surface Processes....Pages 193-224 Carbonate Mounds in the Gulf of Cadiz....Pages 225-255 Conclusions and Outlook....Pages 257-265 Back Matter....Pages 267-298