Pressure system minima in the pressure field. The minima are called low-pressure areas, and the maxima are called high-pressure areas. A "High" is often shown as H, and a "low" is shown as L. Elongated areas of low pressure, or troughs, are sometimes plotted as thick, brown dashed lines down the trough axis. Isobars are commonly used to place surface boundaries from the horse latitudes poleward, while streamline analyses are used in the tropics. A streamline analysis is a series of arrows oriented parallel to wind, showing wind motion within a certain geographic area. Cs depict cyclonic flow or likely areas of
High pressure metamorphic terranes along the Bangong-Nujiang Suture Zone are generally associated with subduction zones. Protoliths of serpentinites are olivine- and pyroxene-dominated. The formation of serpentinites is caused by the release of fluids from subducting hydrated oceanic slabs as they become heated with depth to a maximum temperature of 650-700 °C. Eclogites are high-pressure (HP) to ultrahigh-pressure (UHP) metamorphic rocks that are indicative of subduction zone metamorphism. The eclogites in central Tibet are of Early Mesozoic origin, and they appear to be the result of diachronous collision between the eastern Qiangtang terrane and the western Qiangtang-Lhasa plate, along the linked eastern Bangong-Nujiang-central Qiangtang zone. Located along the western sector