Rates of tectonic uplift can be determined from the age and elevation of stream terraces, flat-surfaced deposits of streambed sediment that represent ancient floodplains. By dating the age of the terraces and measuring the elevation of the terrace, the uplift rate is the difference in elevation of the terraces divided by the difference in ages of the terraces. A terrace at 398 m elevation is 12,500 years old while the current floodplain is 384 m. What is the rate of uplift in mm/yr? rateuplift = mm yr