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
Gulf Trough of roughly , material born of erosion began building up more rapidly in the Gulf Trough, due to the uplifting of the Appalachian Mountains to the north, which provided the primary source of siliciclastic material transported south via rivers and streams. By the Early Miocene, the trough was filled, and materials continued to move southward covering and replacing the carbonate-depositing marine environment with sands, silts, and clays; these sediments created the peninsula on which terrestrial flora and fauna could become established. Gulf Trough The Gulf Trough, also known as the Suwanee Straits, is an ancient geologic feature of Florida present