Statement I: Portions of glacial troughs may exhibit remarkably flat f

Statement I:
Portions of glacial troughs may exhibit remarkably flat floors.
Statement II:
The flat floor in a glacial trough is produced by uniform glacial erosion.

Both the statements are individually true and Statement II is the correct explanation of Statement I

Both the statements are individually true but Statement II is not the correct explanation of Statement I

Statement I is true but Statement II is false

Statement I is false but Statement II is true

Answer is Right!

Answer is Wrong!

This question was previously asked in

UPSC CDS-1 – 2018

Download PDF Attempt Online

Statement I is true; portions of glacial troughs (U-shaped valleys formed by glaciers) often have remarkably flat floors. Statement II is false. While glacial erosion (abrasion and plucking) is responsible for carving the overall U-shape and lowering the valley floor, the characteristic flatness is often achieved not solely by “uniform glacial erosion” (which is rarely truly uniform), but significantly by the deposition of glacial till (ground moraine) and outwash sediments after the ice retreats, filling irregularities on the eroded bedrock floor. Attributing the flatness purely to uniform erosion is inaccurate.

Glacial troughs are characterized by their U-shape, steep sides, and broad, often flat floor. The U-shape is formed by the powerful erosive action of the glacier flowing through a pre-glacial valley.

Processes contributing to the shape and features of a glacial trough include abrasion (grinding action of ice and embedded debris), plucking (lifting and removal of rock fragments), and basal melting. The deposition of ground moraine and later sediments like lacustrine deposits (in lakes formed after deglaciation) plays a crucial role in creating the final flat appearance of the valley floor.

Join Our Telegram Channel

More similar MCQ questions for Exam preparation:-