Tableland

Sedimentary tablelands

Sedimentary tablelands are tablelands that typically have developed from the erosion of coarse-grained, clastic, sedimentary rocks in the form of relatively flat-lying sandstones and conglomerates that have not been strongly deformed by tectonics. The primary control on the geomorphology of sedimentary tablelands is the dip of the layers of the sandstones, conglomerates, and associated sedimentary strata. Sedimentary tablelands only form if the dip of the sedimentary layers is negligible. If the sedimentary layers are tilted, although otherwise little deformed, asymmetric ridges known as cuestas develop.

A really extensive sedimentary tablelands are often known as plateaus. As plateaus are dissected by the headward erosion and incision of river and stream courses and the retreat of their bounding escarpments, plateaus are fragmented into tablelands of smaller and smaller extent known as mesas, buttes, or pinnacles. Further erosion eventually reduces these landforms to piles of bouldery rubble as known as rock labyrinths. The tepui of South America are a type of sedimentary tableland composed of erosional outliers of flat-lying Precambrian quartz arenite sandstone that tower over the surrounding jungle underlain by crystalline basement rocks.