The Sao Tomé deep-sea turbidite system (southern Brazil Basin): Cenozoic seismic stratigraphy and sedimentary processes

Giant mounded drifts in the Argentine Continental Margin: Origins, and global implications for the history of thermohaline circulation

“…The AR4 discontinuity is correlated with AR-I unconformity from Urien et al (1976), and related to the Horizon B defined in the northeast of the Argentine Basin at site DSDP-358 , which marks an important change in sediment facies (Supko and Perch-Nielsen, 1977). The AR4 discontinuity is coeval with the R1/D2 discontinuity in the Brazil Basin (Mézerais, 1991;Mézerais et al, 1993;Lima, 2003;Viana et al, 2003), Discontinuity O in the Indian Ocean (Niemi et al, 2000) e which is coincident with a regional hiatus in the sedimentation (Latimer and Fillipelli, 2002) e and the Marshall Paraconformity in the South Pacific Ocean (Carter et al, 2004). The AR4 discontinuity could also be associated with the extension of ice in East Antarctica (Barron et al, 1989;Cooper et al, 1991) and the beginning of a new THC system that affects the south hemisphere (Supko and Perch-Nielsen, 1977;Kennett, 1982).…”

“…These changes ended after formation of Subunit-c of the UU, when a new oceanographic scenario was completely established and present morphologic features began to develop . The base of the UU could date to the late middle Miocene (Hinz et al, 1999), which is coeval with the R2/R4/D4 discontinuity in the Brazil Basin (Mézerais, 1991;Mézerais et al, 1993;Lima, 2003;Viana et al, 2003), and Reflector-c in the Weddell and Scotia Seas in Antarctica (Maldonado et al, 2006).…”

“…LCDW derives from NADW and, therefore, has existed since the middle Miocene, when the CDW started to split into two fractions (UCDW and LCDW), the ultimate consequences of which, for the Argentine Basin, should have been the onset of LCDW circulation and the deepening of the CDW-AABW interface ). Although these changes should have begun after the base of UU, a more dramatic change occurred in association with the reflection at the top of Subunit c of UU, which has been correlated with R4'/R3/top of U2c discontinuity in the Brazil Basin (Mézerais, 1991;Mézerais et al, 1993;Lima, 2003;Viana et al, 2003); Discontinuity P in the Indian Ocean (Niemi et al, 2000); an unconformity in the South Pacific Ocean (Carter et al, 2004); a hiatus in the Southern Ocean (Ledbetter and Ciesielski, 1986); and Reflector-b in Antarctica (Maldonado et al, 2006). Therefore, the reflection could date to late Miocene/early Lower Pliocene, for which there is major evidence of relatively strong activity in the intermediate and deep-water circulations (Sykes et al, 1998).…”

Submarine slide blocks and associated soft-sediment deformation in deep-water basins: A review

“…Data processing included resampling, spherical divergence corrections and zero-phase conversions undertaken prior to stacking, 3D pre-stack time migration using the Stolt algorithm and one-pass 3D migration. Published borehole data from Deep Sea Drilling Program (DSDP) Sites 356 (Kumar et al, 1997) and 515/516 (Barker, 1983;Barker et al, 1983;Gambôa et al, 1983), as well as the works of Bruhn and Walker (1997), Chang et al (1992), Meisling et al (2001), Viana et al (2003), Fiduk et al (2004) and França et al (2007), were used to identify and date seismicstratigraphic units with submarine slide blocks. Based on the dominant frequency of the interpreted seismic volume (40 Hz), vertical seismic resolution varies between 12 and 19 m in blockladen strata.…”

“…On the Canary Islands, Watts and Masson (2001) and Masson et al (2002) used sidescan sonar data to show that the north flank of Tenerife has been subjected to a minimum of four major slides during the past 1.0 Ma ( Fig. 1 On the flanks of the Stromboli Volcano, Casalbore et al (2011) recognised blocks in areas associated with large-scale sector collapses that were capable of generating tsunami waves ( Fig.…”