Barchan and Longitudinal dunes.

Question

Differentiate between:

Barchan and Longitudinal dunes.

Answer 1

Barchan	Longitudinal dunes
(i) When there is an obstacle in the path of wind, or due to low velocity of wind, the sand gets dropped at some places. Thus, barchans are formed.	(i) When sand is deposited parallel to the direction of wind, longitudinal dunes are formed.
(ii) Barchans are crescentshaped dunes. The slope that faces the wind is gentle whereas the opposite slope is steep.	(ii) They appear parallel to the wind direction. Sometimes they are 100km long.
(iii) Barchans migrate from one place to another.	(iii) Longitudinal dunes do not migrate but extend in the wind direction.
(iv) They are seen in the Great Indian Desert of Rajasthan.	(iv) They are seen in Rub-alKhali desert of Saudi Arabia.