The correct option is 2 only
Explanation
Outwash plains are fluvio-glacial depositional landforms formed by the accumulation of sediment carried by meltwater streams flowing away from a glacier. They represent a transition from direct glacial action to fluvial (river) processes.
Statement 1 is Incorrect:
Outwash plains are situated at the foot of glacial mountains or beyond the terminal limits of continental ice sheets. As glaciers melt, streams of water discharge from the ice front, carrying debris and depositing it over a broad area in front of the terminal moraines.
Statement 2 is Correct:
Outwash plains are composed of stratified drift, meaning the sediments are sorted and layered by the action of running water. Heavier materials are deposited first, followed by finer sands and silts. Glacial till, on the other hand, refers to unassorted, unstratified material deposited directly by the ice (e.g., in moraines). Therefore, outwash plains consist of sorted alluvium, not unassorted till.
Statement 3 is Incorrect:
When meltwater streams emerge from a confined valley, they often form fan-shaped deposits known as outwash fans. These are morphologically similar to alluvial fans. An extensive outwash plain is often formed by the coalescence of multiple outwash fans.
Key Takeaway:
The defining characteristic of an outwash plain is that it is formed by meltwater, resulting in sorted and stratified sediments, unlike moraines which are formed by ice and contain unassorted till.