Earth-Science Reviews ( IF 9.724 ) Pub Date : 2020-07-25 , DOI: 10.1016/j.earscirev.2020.103302 Piotr Migoń
Conglomerates are widespread clastic rock, often occurring in thick successions and supporting complex geomorphological landscapes. Yet, by contrast to some other rock types, little systematic work has been done on geomorphology of conglomeratic terrains, major geographical gaps exist, and no review has been offered up to now. This paper partially fills this gap and provides an overview of characteristic landforms, landscape types and geologic controls present in areas built of conglomerates. Distinctive landforms developed in conglomerates include bedrock cliffs and overhangs, domed hills and hilltops, crags, slots and clefts, tafoni, caves and various karst features. They combine into specific landform assemblages of dome clusters, dissected plateaus and cuestas, stepped hillslopes and conglomeratic badlands if lithification of sediment is poor. Some dissected plateaus and dome clusters represent spectacular morphology, awarded the status of UNESCO World Heritage (China Danxia, Meteora, Kata Tjuta). A variety of geological controls is identified and presented, including composition of conglomerate packages, their thickness, jointing patterns, presence of sandy and clayey intercalations, as well as the style and magnitude of regional uplift. Clast-by-clast breakdown is identified as a principal mechanism of rock disintegration, analogous to grain-by-grain disintegration pattern of many sandstones. This explains striking similarities between some sandstone and conglomeratic sceneries and the common presence of rounded shapes. In the closing part of the paper research avenues for the future are suggested. Both regional studies, aimed at the complete inventory of conglomeratic landforms, as well as detailed insights into the nature of bedrock control at the variety of scales are recommended.