what is the extent of the thar desert
Thar Desert The Thar Desert, also known as the Great Indian Desert, is a large, arid region in the northwestern part of the Indian subcontinent that forms a natural boundary between India and Pakistan. It is the world's 17th largest desert, and the world's 9th largest subtropical desert.[1] About 75% of the Thar Desert is in India, and the remaining 25% is in Pakistan.[2] In India, it covers about 320,000 km2 (120,000 sq mi), forming approximately 10% of the total geographic area of India. More than 60% of the desert lies in the state of Rajasthan and extends into Gujarat, Punjab, and Haryana.[3] This desert comprises a very dry part, the Marusthali region in the west, and a semidesert region in the east with fewer sand dunes and slightly more precipitation.[4]
Tharsis Geologic evidence, such as the flow direction of ancient valley networks around Tharsis, indicates that the bulge was largely in place by the end of the Noachian Period,[24] some 3.7 billion years ago.[26] Although the bulge itself is ancient, volcanic eruptions in the region continued throughout Martian history and probably played a significant role in the production of the planet's atmosphere and the weathering of rocks on the planet's surface.[27] By one estimate, the Tharsis bulge contains around 300 million km3 of igneous material. Assuming the magma that formed Tharsis contained carbon dioxide (CO2) and water vapor in percentages comparable to that observed in Hawaiian basaltic lava, then the total amount of gases released from Tharsis magmas could have produced a 1.5-bar CO2 atmosphere and a global layer of water 120 m thick.[24] Martian magmas also likely contain significant amounts of sulfur and chlorine. These elements combine with water to produce acids that can break down primary rocks and minerals. Exhalations from Tharsis and other volcanic centers on the planet are likely responsible for an early period of Martian time (the Theiikian[28]) when sulfuric acid weathering produced abundant hydrated sulfate minerals such as kieserite and gypsum.