What global religion originated in south asia?

 Hinduism originated in South Asia and is the dominant religion there today. The Vedas, as well as classic indian customs formed modern day Hinduism. Before the rise of Hinduism, Buddhism was the most popular religion in India, especially along the Ganges and south (Tamilnad) India, so aspects of Buddhism were also incorporated into Hinduism to increase its appeal. In hindu belief, Buddha is the 7th reincarnation of Vishnu. In the years following this Buddhism was essentially exiled, and thus is a minority religion in modern India

Idon't know. the question you are trying to ask doesn't make sense.

Geothermic gradient is the rate of increasing temperature with respect to increasing the depth in the earths interior. away from tech tonic plates boundaries, it is about 25-40 c/km (72-87 degrees f/mi) of depth near the surface in most of the world.