There is no consistency in varve structure. Other Nonseasonal Causes Of Lamination Geologists have suggested other causes of lamination as potential contributors to varves, including storm events, turbidites and glacial meltwater. Each one of these is aperiodic, producing laminations with no relation to annual, cyclic processes. For example, turbidity currents from melting snow or heavy rain produce extra couplets. Many supposed varves are multiple turbidity current deposits and do not represent seasonal changes.
Turbidity flows have the surprising ability to deposit silt and clay quickly in equal thicknesses.
Under normal conditions, silt usually settles in a few days and clay can take years to settle. As both clay and silt fractions are transported to the site of deposition at the same time, successive surge deposits are likely to have similar proportions of silt and clay. In other words, thick silt layers will have thick clay layers, and thin silt layers will have thin clay layers. In many cases where large ice lobes or glaciers sit or float in lakes, there is year round delivery of sediments and turbidite activity occurs almost continually resulting in graded laminae that are not true varves. How many varve-like layers form from year to year becomes anyone's guess.