ABSTRACT
In the simplest case, we can consider a series of strata whose outcrop is horizontal. Rarely are they so in nature; they are frequently found elevated hundreds of metres above their position of deposition, and tilting and warping have usually accompanied such uplift. The pattern of outcrops of the beds where the strata are horizontal is a function of the topography; the highest beds in the sequence (the youngest) will outcrop on the highest ground and the lowest beds in the sequence (the oldest) will outcrop in the deepest valleys. Such a horizontal orientation is rare in Britain but would be typical of road cuttings, say, in the Great Plains of western USA (Fig. 2.1). The individual beds are separated by bedding planes. These are successive surfaces of deposition and represent the earth’s surface during the time between individual sedimentary deposition phases. The outcrop contains no other geological features except for a few joints, formed either through tension during its vertical uplift or by decompaction as former sedimentary layers above have been removed. The Great Plains of western USA – a typical roadside section. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780203783795/dfde4bb4-fdec-469e-b9c5-45b632a83daf/content/fig2_1.jpg" xmlns:xlink="https://www.w3.org/1999/xlink"/> Horizontal bedding. View from the South Rim, Grand Canyon, Arizona. This large erosional feature exposes horizontally bedded sedimentary rocks (also see Map 1). https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780203783795/dfde4bb4-fdec-469e-b9c5-45b632a83daf/content/pla1.jpg" xmlns:xlink="https://www.w3.org/1999/xlink"/>
