Factors controlling ebro deep-sea fan growth, Mediterranean Sea

Conference · Tue Jan 01 00:00:00 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-
• Journal Information: Geol. Soc. Am., Abstr. Programs; (United States), Vol. 17; Conference: 98. annual meeting of the Geological Society of America, Orlando, FL, USA, 28 Oct 1985
• Country of Publication: United States
• Language: English

Related Subjects

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