Monsoon trough of the summertime Asian monsoon is in its normal orientation (oriented east-southeast to west-northwest), tropical cyclones along its periphery will move with a westward motion. If it reverses its orientation, orienting southwest to northeast, tropical cyclones will move more poleward. Tropical cyclone tracks with S-shapes tend to be associated with reverse-oriented monsoon troughs. The South Pacific convergence zone and South American convergence zones are generally reverse oriented. The failure of the monsoon trough, or the ITCZ, to move south of the equator in the eastern Pacific Ocean and Atlantic Ocean during the southern hemisphere summer, is considered one of the
Rockall climate without heat or cold extremes. Rockall is made of a type of peralkaline granite that is relatively rich in sodium and potassium. Within this granite are darker bands richer in iron because they contain two iron-sodium silicate minerals called aegirine and riebeckite. The darker bands are a type of granite that geologists have named "rockallite", although use of this term is now discouraged. In 1975, a mineral new to science was discovered in a rock sample from Rockall. The mineral is called bazirite, named after the chemical elements barium and zirconium. Bazirite has the chemical composition BaZrSiO. Rockall forms