Previous   |    Next

doi:10.2204/iodp.proc.307.209.2009

Introduction

During Integrated Ocean Drilling Program Expedition 307, Challenger Mound (51°22.8′N, 11°43.1′W; water depth = 781–815 m) (Fig. F1) was drilled to unveil the nature and origin of the deepwater carbonate mounds by clarifying the microbial role in mound construction and assessing whether past geofluid migration events acted as a prime trigger for mound genesis (see the “Expedition 307 summary” chapter). In order to resolve the first assumption, the main objectives of this study were to describe the biologic and lithologic composition (including mineralogy) of the mound and its organic matter content. Challenger Mound developed in the Belgica Mound Province on the eastern slope of Porcupine Seabight (Fig. F1), where 66 conical mounds (single or in elongated clusters) occur at depths from 550 to 1025 m. The mounds are partly enclosed in an impressive set of contourites (Van Rooij et al., 2003). They are as high as 160 m and rest on a seismically discontinuous surface (De Mol et al., 2002; Huvenne et al., 2003). A coral ecosystem dominated by the coldwater coral Lophelia pertusa covers some mounds, whereas Challenger Mound is topped by dead coral rubble (Foubert et al., 2005).

Top of page   |    Previous   |    Next