southeast on the Pakistani side of the Indian border is called the Cholistan Desert and, on the Indian side, the Thar Desert. The Indus then flows through a gorge near Sukkur and the fertile plains region of Sindh, forming a large delta region between the border of Gujarat, India and Pakistan, finally terminating in the Arabian Sea near the port city of Karachi, Pakistan. During floods, Indus river water flows in to Indian part of Great Rann of Kutch. Thus Gujarat state of India is also a riparian state of Indus river as Rann of Kutch area lying west of Kori Creek in the state is part of the Indus River Delta. Puranic Mention and Etymology In the Chaitra-Ratha Parva of Adi Parva of Mahābhārata, when sage Vasishṭha wants to commit suicide he saw the river named Haimāvata (whose source is Himavat), flooded and full of crocodiles and other aquatic monsters. So he jumps into the river. The river thinking that Vasishṭha is a mass of unquenchable fire dilated itself and flew in a hundred different directions. Henceforth the river was named śatadra (or śatadru) which means the river of a hundred courses. So, Vasishṭha landed on dry land and was unharmed. Langqên Zangbo Langqên Zangbo (; ) is a river in Ngari, Tibet, China. The name Langqên, Tibetan for "elephant", is because of a valley that resembles an elephant trunk. This river is the main source of the Sutlej, a tributary of Indus River. It enters India at Shipki La pass. The source is south of Gangdise Range, in Ngari Prefecture. Its course is mainly in the Zanda County. The river drains an area of 22,760 km2, and covers a length of 309 km. The drop in height is 3,256 m. Historically, the river was the centre of the Zhangzhung Kingdom until its fall in the 8th century AD. Geology Sutlej is an antecedent river, which existed before the Himalayas and entrenched itself while they were rising. The Sutlej, along with all of the Punjab rivers, is thought to have drained east into the Ganges prior to 5 mya. There is substantial geologic evidence to indicate that prior to 1700 BC, and perhaps much earlier, the Sutlej was an important tributary of the Ghaggar-Hakra River (thought to be the legendary Sarasvati River) rather than the Indus, with various authors putting the redirection from 2500 to 2000 BC, from 5000