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Site U14001

Expedition 340 Scientists2

Background and objectives

Integrated Ocean Drilling Program (IODP) Site U1400 (proposed Site CARI-07C; 14°32.58′N, 61°27.55′W; 2745 meters below sea level [mbsl]) is located west of Martinique (Fig. F1). Site U1400 was dedicated to the study of debris avalanche emplacement and associated erosional processes. The evolution of the active Montagne Pelée Volcano is characterized by three major flank-collapse events (~0.1 m.y., ~25,000 y, and ~9000 y ago) that systematically destroyed the western flank of the volcano (Le Friant et al., 2003; Boudon et al., 2005, 2007). The volume of material displaced by these collapses varies from 2 to 25 km3, with the debris avalanches depositing into the Grenada Basin. The Pitons du Carbet Volcano experienced a sector collapse 0.3 m.y. ago (Boudon et al., 1992, 2007; Samper et al., 2007). As shown by bathymetric and seismic data obtained during several site surveys, drilling to 510 meters below seafloor (mbsf) would penetrate through volcanic and biogenic sediment with intercalated large chaotic units (interpreted as debris avalanche Deposits 1 and 2). Of particular interest are the contacts between the different units, not only to distinguish between the different deposits but also to better understand mass transport dynamics, especially in the basal part of the flow. This study will provide fundamental constraints on friction parameters needed for realistic avalanche propagation models. Sediment above the deposit will be dated using δ18O chronostratigraphy to better constrain the age of this event. As shown on the seismic profiles, a thick and well-bedded sedimentary layer (~70 m) overlies Deposit 2 with an abnormal thickness toward the northeast. We will test the hypothesis that, following a flank collapse, the on-land drainage system is drastically modified, resulting in increased erosion and, therefore, increased sedimentation rates in the Grenada Basin.

1 Expedition 340 Scientists, 2013. Site U1400. In Le Friant, A., Ishizuka, O., Stroncik, N.A., and the Expedition 340 Scientists, Proc. IODP, 340: Tokyo (Integrated Ocean Drilling Program Management International, Inc.). doi:10.2204/​iodp.proc.340.110.2013

2Expedition 340 Scientists’ addresses.

Publication: 17 August 2013
MS 340-110