FN Archimer Export Format
PT J
TI Sedimentation adjacent to atolls and volcano-cored carbonate platforms in the Mozambique Channel (SW Indian Ocean)
BT 
AF COUNTS, John
   JORRY, Stephan
   LEROUX, Estelle
   MIRAMONTES, Elda
   JOUET, Gwenael
AS 1:1;2:1;3:1;4:2;5:1;
FF 1:;2:PDG-REM-GM-LGS;3:PDG-REM-GM-LGS;4:;5:PDG-REM-GM-LGS;
C1 Inst Francais Rech Exploitat Mer IFREMER Pointe D, Lab Geodynam & Enregistrement Sedimentaire GM LGS, F-29280 Plouzane, France.
   IUEM UBO, CNRS, Lab Geosci Ocean, UMR6538, F-29280 Plouzane, France.
C2 IFREMER, FRANCE
   CNRS, FRANCE
SI BREST
SE PDG-REM-GM-LGS
UM LGO
IN WOS Ifremer jusqu'en 2018
   copubli-france
IF 3.349
TC 33
UR https://archimer.ifremer.fr/doc/00450/56136/57802.pdf
LA English
DT Article
CR PAMELA-MOZ01
   PAMELA-MOZ04
   PTOLEMEE
BO L'Atalante
   Pourquoi pas ?
DE ;Atoll;Carbonate;Indian Ocean;Slope;Deepwater sediments
AB Recently acquired data from the Iles Eparses (southwestern Indian Ocean) reveal new information about the geomorphology, depositional processes, and sedimentary deposits on the slopes of atolls and atoll-like platforms. The deposits discussed here lie on the deepwater flanks of isolated, inactive volcanos that are capped by shallow, relatively flat carbonate platforms 45–210 km2 in area. Much of the slope geomorphology is controlled by the underlying volcanic edifice. Steep (~25–35°) upper slopes consist of outcrops of volcanic basement, smooth banks, failure scarps, and channels. Sedimentary features seen in the lower slope and proximal basin (2000–3500 m deep) consist of channels, levees, lobes, and mass transport deposits (MTDs). In places, channels terminate 13–18 km from the platform margin, ending in lobes up to 3.5 km across, a feature not often seen in modern carbonates. In the subsurface, MTDs are present near all platforms. Within MTDs, seismic character is variable, often consists of chaotic reflections indicative of sediment gravity flow processes. Subsurface units with organized (retro- or progradational) reflections are interpreted as turbidite lobes or MTDs with compressional features. Core taken within lobes and near the base of slopes reveal decimeter-scale turbidites and debrites composed primarily of graded and massive bioclastic grainstones and packstones with abundant neritic skeletal components, interbedded with hemipelagic aragonitic and clay-rich foraminiferal ooze. Slope depositional processes are therefore primarily gravity-driven and occur at different scales; i.e., bed-scale turbidites and muds may be remobilized and redeposited through slope failure and deposition of large MTDs. Dominant wind direction may also play a role in slope sedimentation: leeward slopes are generally less rugose and show increased sedimentation at the toe of the slope. This study thus provides new insight into depositional systems surrounding atoll-like carbonate platforms, and provides a new analogue for similar deposits in the geologic record. 
PY 2018
PD OCT
SO Marine Geology
SN 0025-3227
PU Elsevier Science Bv
VL 404
UT 000444790300004
BP 41
EP 59
DI 10.1016/j.margeo.2018.07.003
ID 56136
ER

EF