4-452: A balancing rock , also called a balanced rock , precariously balanced rock (PBR) , or precarious boulder , is a naturally occurring geological formation featuring a large rock or boulder, sometimes of substantial size, resting on other rocks, bedrock , or on glacial till . Some formations known by this name only appear to be balancing, but are in fact firmly connected to a base rock by a pedestal or stem. No single scientific definition of
8-469: Is an important task in most civil engineering projects. Superficial deposits can be very thick, such that the bedrock lies hundreds of meters below the surface. Exposed bedrock experiences weathering , which may be physical or chemical, and which alters the structure of the rock to leave it susceptible to erosion . Bedrock may also experience subsurface weathering at its upper boundary, forming saprolite . A geologic map of an area will usually show
12-451: Is the solid rock that underlies looser surface material. An exposed portion of bedrock is often called an outcrop . The various kinds of broken and weathered rock material, such as soil and subsoil , that may overlie the bedrock are known as regolith . The surface of the bedrock beneath the soil cover (regolith) is also known as rockhead in engineering geology , and its identification by digging, drilling or geophysical methods
16-412: The term exists, and it has been applied to a variety of rock features. Types of feature that the term has been applied to include: India Australia Vietnam Myanmar Canada United States Mexico Argentina Bedrock In geology , bedrock is solid rock that lies under loose material ( regolith ) within the crust of Earth or another terrestrial planet . Bedrock
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