Relationship between large rivers and granite-cored anticlines in the Lower Pearl River System, Southeast China: An example of a long-lived drainage pattern

The larger rivers in the lower Pearl River system of SE China typically avoid outcrops of late Mesozoic granite while most of the smaller rivers transect or originate in granite. It is difficult to explain this phenomenon in terms of probability, lithology, fault control or present day topography. Analyses of sediments, planation surfaces and topography in the lower Pearl River system, indicates that distribution of most of the larger rivers is pre-Oligocene. Late Mesozoic granite exposures are typically located in cores of anticlines implying that both were coeval. These structures were developed at shallow depths and resulted in the formation of topographic highs that controlled the ancient drainage pattern of the present Lower Pearl River system. Despite exhumation of the upper part of the deformed granite, the rivers mostly retained their initial courses, i.e. skirting the granite-cored anticlinal highs and traversing adjacent areas of red bed deposition. Uplift of the SE China mainland during the Oligocene caused incision of much of the river system preserving the late Cretaceous drainage pattern.