Bedrock

Definition

Bedrock consists of “soils and rocks that were in place before the Quaternary Period” (British Geological Survey 2011). This definition may be classified as “a stratigraphical criterion”.

The concept of bedrock in geosciences has, despite it’s apparent simplicity and worldwide use, different meanings accordingly to the different fields of activity in which it is applied. Thus, all magmatic, metamorphic or sedimentary rocks, beside sedimentary soils older than about two million years, exposed at the Earth’s surface (outcrop) or overlain by unconsolidated deposits form the bedrock of a region. But, sometimes, a sedimentary layer from the Quaternary Period, may be classified as bedrock if it was subjected to tectonic stress, reflected in visible folds or faults and lithification. It is appropriate to apply this second “tectonic criterion” in seismic regions, where tectonic stress is still active (Florea 1969).

In contrast, unconsolidated Quaternary deposits, as alteration...