Which process causes the stratification of grain sizes within an alluvial fan deposit?

💡 Explanation

When sediment laden water slows abruptly on an alluvial fan, density sorting occurs because heavier, coarser grains settle out first near the apex, while lighter, finer grains are carried further downslope. Therefore, density sorting results, rather than chemical precipitation, thermal convection or electrostatic attraction, which do not significantly contribute to grain size stratification.

• Which mechanism causes increased crustal melting during oceanic plate subduction under continental crust?
• Which mechanism contributes to tsunami formation along subduction zone fault lines during earthquakes?
• Which outcome primarily results in arid landscapes downstream of large alluvial fans due to water management?
• Which mechanism causes formation of placer deposits near oxbow lakes during fluvial transport?
• Which displacement occurs to a high-altitude projectile launched eastward from a point at 30 degrees North latitude?
• Which volcanic hazard leads to increased rates of glacial ice melt during a subglacial eruption?