Quaternary deposits: The term ‘‘drift’’ refers to unconsolidated material picked up, transported, and redeposited primarily by which agent?

Introduction / Context:
In engineering geology, “drift” commonly denotes glacial deposits including till (directly from ice) and stratified drift (deposited by meltwater). Recognizing the origin helps anticipate variability, particle sizes, and compaction characteristics relevant to foundations and excavations.

Given Data / Assumptions:

• Quaternary geomorphology terminology.
• Focus on the generic agent responsible for drift.
• Unconsolidated, mixed, often heterogeneous deposits.

Concept / Approach:

Drift encompasses deposits formed by the action of glaciers and their meltwaters. Wind-blown sediments are termed aeolian (loess, dune sands) and are not “drift,” while simple gravitational creep is a different mass wasting process. Hence, the correct agent is glacial ice and associated meltwater (glaciofluvial).

Step-by-Step Solution:

Verification / Alternative check:

Geology references classify till and stratified drift as subtypes of glacial drift, confirming the answer.

Why Other Options Are Wrong:

(a) Aeolian is different; (b) creep alone does not generate drift; (d) “All the above” is incorrect because drift is not caused by wind or gravity-only processes; (e) is unrelated.

Common Pitfalls:

Using “drift” loosely for any transported deposit; equating loess with drift.

Final Answer:

Glaciated water and ice (glacial and glaciofluvial processes)