T228 The Effects of Discharge Variability on Alluvial Stratigraphy: Toward a New Facies Model

Tuesday, 27 September 2016
1:30 PM - 5:30 PM
Room 401

ANALYSIS OF MULTI-DECADAL (1960-2010) DYNAMICS IN SEDIMENT AND WATER DISCHARGES FROM GLOBAL RIVERS: TEMPORAL VARIABILITY AND INTRA-BASIN CONTROLS

Paper number: T228-2
Program: Technical Sessions
Time: 1:40 PM – 1:55 PM

Authors

Abstract

We study changes in global riverine water discharge and sediment flux over a 50-year period, 1960–2010, using the WBMsed v.2.0 global hydrological water balance model. Normalized departure from an annual mean is used to quantify spatial and temporal dynamics at continental scale. Coefficient of variance analysis is used to quantify temporal variability in large global rivers.

Considerable intra-basin variability in both water and sediment discharge is observed in different regions of the world. A correlation analysis between continental-averaged suspended sediment and water discharge shows that yearly changes in intra-basin precipitation dynamics explain most of the discrepancies between water discharge and suspended sediment. The mechanism proposed and demonstrated here (for the Ganges, Danube and Amazon Rivers) is that regions with high relief and soft lithology will amplify the effect of higher than average precipitation by producing an increase in sediment yield that greatly exceeds increase in water discharge. Preliminary analysis of the effect of sediment variability on large tropical deltas and a new bedload module are also presented.

Geological Society of America Abstracts with Programs. Vol. 48, No. 7

doi: 10.1130/abs/2016AM-280555

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