Sedimentary processes at the mouth of a tidally?influenced delta: New insights from submarine observatory measurements, Fraser Delta, Canada
نویسندگان
چکیده
This paper examines particle settling dynamics in a tidally-influenced delta, including observations of convective settling, strongly modulated by seasonal discharge and tidal cycles. Long time series Acoustic Doppler Current Profiler backscatter, proxy for suspended sediment concentration the water column, current accumulation measurements from slope Fraser River delta show variability sedimentary processes over timescales semi-diurnal to annual. backscatter shows lagged response river strong diurnal/semi-diurnal variability. Most cycle is characterized buoyant effluent plume. During ebbing phase diurnal major tides, discrete events are observed extending through entire column. The pulse-like nature these result downward plunging fingers characteristic similar those laboratory flume experiments, appear be initiated at interface between surface plume underlying ambient water. Currents three-layer offshore southward directed transport sediments. remaining column influenced flows, but near intermediate water-depth currents out several hours, indicating stratification basin decoupled propagation internal tides. lag unlikely cause discernible facies changes, may have implications basin-fill patterns restricted basins with range. results this work will help better understand mouth sedimentation dispersal other modern deltas geological record.
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ژورنال
عنوان ژورنال: Sedimentology
سال: 2021
ISSN: ['1365-3091', '0037-0746']
DOI: https://doi.org/10.1111/sed.12868