Chakra is the combination of the physical energy found within the body and spiritual energy gained through practice. Using deferent methods, like hand seals, it can be manipulated to allow the user to perform superhuman feats.
Elemental chakra is the advanced form of chakra that is converted into one of the Five Elements of Chakra, which are fire, wind, lightning, earth, and water, or katon, futon, raiton, doton, and suiton respectively.
The creation of katon requires the superheating of chakra, and the creation of futon relies on the thinning of chakra. Raiton is generated through the increased high frequency vibrations of chakra. I assume that doton requires the user to release their chakra into some type of earth to manipulate it, but the earth could also be created using said chakra. And finally, suiton can be used by the releasing of chakra into a pre-existing water source to manipulate it, or the creation of it by increasing the density of the chakra while cooling it at the same time.