Record and provenance of Pleistocene volcaniclastic turbidites from the central Lesser Antilles (IODP Expedition 340, Site U1398B)

A 1.5 Ma Marine Record of Volcanic Activity and Associated Landslides Offshore Martinique (Lesser Antilles): Sites U1397 and U1399 of IODP 340 Expedition

“…Eruptions ages: most 14 C dates for Mt Pelée are relatively old measurements by bêta counting (gray zone: all ages out of 14 C dating range; Traineau et al, 1989) In core U1397A, only few tephra glasses have Si-and K-rich glass compositions, which may correspond to Roseau Tuff eruption, and the coexistence, in the same tephra layers, of K-poor glasses that are absent in Dominica products also favor the Mt Pelée source (Figure 10B). In general, in these cores offshore Martinique, very few tephra deposits originate from Dominica, except in core U1398 at the front of Martinique SLDs in the Grenada Basin, which almost exclusively contains material from Dominica (Breitkreuz et al, 2021). The different types of tephra products (dome or Plinian clasts or scoriae) in cores CARMAR 4 and U1397A are not investigated in this study, but preliminary petrological data on U1397A tephra (Del Manzo et al, in prep.…”

“…Site U1398 is the most distant (~80 km) from the shore, beyond the chaotic facies deposits (Figure 1B). It mainly contains volcaniclastic turbidites (>70%-95%, Le Breitkreuz et al, 2021) due to its location on the low slopes inside the Grenada Basin which channeled most turbidity currents from the western flank of the Arc (Figure 1). The composition of volcanic clasts, age range, and isotopic and trace element compositions of zircons suggest that the majority of these turbidites originate from Dominica (Breitkreuz et al, 2021).…”

“…It mainly contains volcaniclastic turbidites (>70%-95%, Le Breitkreuz et al, 2021) due to its location on the low slopes inside the Grenada Basin which channeled most turbidity currents from the western flank of the Arc (Figure 1). The composition of volcanic clasts, age range, and isotopic and trace element compositions of zircons suggest that the majority of these turbidites originate from Dominica (Breitkreuz et al, 2021). Site U1401, the closest to the shore, penetrates the sediments over 15 m down to the blocky deposit whose drilling was unsuccessful due to its high content in large volcanic blocks, characteristic of a DAD (DAD 3;Figure 1B;Le Friant et al, 2015).…”

“…Tephra: the different colors correspond to arbitrary subdivisions according to the SiO 2 and K 2 O concentrations. Small black circles: tephra and turbidites of core U1398B (0-900 ka, Breitkreuz et al, 2021). Black crosses: tephra and turbidites of core U1401A (0-36 ka; Solaro et al, 2020).…”