Low-pressure area Low-pressure area A low-pressure area, low, depression or cyclone is a region on the topographic map where the atmospheric pressure is lower than that of surrounding locations. Low-pressure systems form under areas of wind divergence that occur in the upper levels of the troposphere. The formation process of a low-pressure area is known as cyclogenesis. Within the field of meteorology, atmospheric divergence aloft occurs in two areas. The first area is on the east side of upper troughs, which form half of a Rossby wave within the Westerlies (a trough with large wavelength that extends through the troposphere). A second
High pressure metamorphic terranes along the Bangong-Nujiang Suture Zone localized shearing between coherent lithospheric blocks is proposed to explain the high elevations observed in Tibet. Oblique subduction and large-scale sinistral strike-slip faults leading to eastward extrusion of lithospheric material would be responsible for the growth of Tibet to the east. High pressure metamorphic terranes along the Bangong-Nujiang Suture Zone High pressure terranes along the ~1200 km long east-west trending Bangong-Nujiang suture zone (BNS) on the Tibetan Plateau have been extensively mapped and studied. Understanding the geodynamic processes in which these terranes are created is key to understanding the development and subsequent deformation of the BNS and Eurasian deformation as