Factors controlling ebro deep-sea fan growth, Mediterranean Sea

Conference · Tue Jan 01 04:00:00 EST 1985 · Geol. Soc. Am., Abstr. Programs; (United States)

OSTI ID:6320029

Nelson, C H; Maldonado, A; Alonso, B; Palanques, A; Ryan, W B.F.; Kastens, K; O'Connel, S

Tectonic, sediment-source and sea-level factors control depositional patterns of the Ebro deep-sea fan system. In unstable, steep continental slope terrain, mass movement of material results in wide gullied canyons and formation of non-channelized debris aprons. These fan channels develop low sinuosity and generally traverse the continental rise without feeding into depositional lobes because of steep gradients (1:50 to 1:100) and sediment draining into the subsiding Valencia Valley graben. An abundance of sediment input points from mass failure and many river-fed canyons contributes to a depositional pattern of side-by-side debris aprons and separate channel-levee complexes. When a large sediment supply feeds a channel for a relatively long period 1) fan valley sinuosity increases: 2) channel walls are modified through undercutting, slumping, and crevasse splays: 3) channel bifurcation occurs: 4) incipient depositional lobe formation begins. Lowering of sea levels in Late Pleistocene time permitted the access of coarse river sediment to slope valleys and promoted deposition of numerous turbidites and active growth of the fan. During the Holocene, when sea levels have been high, a regime of hemipelagic sedimentation, mass movement, and debris apron sedimentation has dominated.

• Research Organization: Geological Survey, Menlo Park, CA (USA)
• OSTI ID: 6320029
• Report Number(s): CONF-8510489-
• Conference Information: Journal Name: Geol. Soc. Am., Abstr. Programs; (United States) Journal Volume: 17
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580100* -- Geology & Hydrology-- (-1989)
580500 -- Oceanography-- (1980-1989)
ALLUVIAL DEPOSITS
CENOZOIC ERA
CONTINENTAL MARGIN
CONTINENTAL SLOPE
DEPOSITION
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC HISTORY
GEOLOGY
GEOMORPHOLOGY
LEVELS
MEDITERRANEAN SEA
OCEANOGRAPHY
PLEISTOCENE EPOCH
QUATERNARY PERIOD
SEA LEVEL
SEAS
SEDIMENTS
SLOPE STABILITY
STABILITY
SUBMARINE CANYONS
SURFACE WATERS