Q 1(b). What are sheath folds? Discuss the deformational conditions of their formation. (UPSC 2025, 10 Marks, 150 Words)

Theme: Sheath Folds: Formation and Deformational Conditions Where in Syllabus: (Geology)
शीय वलन क्या होते हैं? इनकी उत्पत्ति की विरूपण अवस्था की विवेचना कीजिये ।