Architecture of Glaciotectonic Complexes

Abstract

Glaciotectonic studies are an integrated part of the Quaternary geological research carried out by the Danish geological survey. Almost all the hilly areas in Denmark were created or affected by glaciotectonic deformations, and the features are included in the mapping of surface near deposits. For the mapping and support of constructing 3D geological models a classification of architecture of glaciotectonic complexes is suggested. The important elements for classification of architecture are the surfaces. Four orders of surfaces are defined for glaciotectonic complexes: first-order surfaces are décollement surfaces and glaciotectonic unconformities; second-order surfaces are ramps and flats-the thrust faults; third-order surfaces are folded beds-anticlines and synclines; and fourth-order surfaces are small scale folds and faults-kink bands, conjugate faults, box folds, etc. The most important first-order surface is the décollement surface. This surface limits the glaciotectonic complex at its base and controls the extent of glaciotectonic disturbances. Below this surface, ordinary flat lying planar bedding occurs, whereas above the surface a number of structures are present characteristic of second-to fourth-order elements in the glaciotectonic architecture. The other first-order surface is the topographic top of the glaciotectonic complex, which eventually may be replaced by a truncating unconformity.

Glaciotectonic deformations in the Jammerbugt and glaciodynamic development in the eastern North Sea

“…In glaciotectonic architecture, the primary first‐order surface is the décollement or detachment surface (Pedersen, ). In general the depth to this surface will increase from the distal to the proximal zone in a thrust‐fault complex.…”

“…The horizontal reflectors are interpreted as a highstand marine transgressive sequence in a glaciodynamic sequence system (Pedersen, ). The erosional unconformity at the base of this sequence may be defined as the second first‐order surface in relation to the glaciotectonic architecture (Pedersen, ). The onlapping marine sequence is interpreted as the more than 100‐m‐thick upper Pleistocene mud of the Skærumhede Group (Pedersen, ).…”

“…During the glacial advances of the Eurasian Ice Sheet, several large glaciotectonic complexes were formed in the proglacial, foreland‐progressing ice margin (Pedersen, ). Most of these were formed during the Saalian and Weichselian glaciations, and in general the Saalian glaciotectonic complexes are preserved onshore Europe with glaciotectonic–geomorphic features south of the Main Stationary Line of the Weichselian Scandinavian Ice Sheet (Aber and Ber, ).…”

“…Most of these were formed during the Saalian and Weichselian glaciations, and in general the Saalian glaciotectonic complexes are preserved onshore Europe with glaciotectonic–geomorphic features south of the Main Stationary Line of the Weichselian Scandinavian Ice Sheet (Aber and Ber, ). North of the Main Stationary Line the preserved and landscape‐forming glaciotectonic complexes were formed during the last Weichselian glaciation, and older glaciotectonic complexes are only known from superimposed deformations or deformed Quaternary successions (Ehlers, ; Pedersen, , , ). The major complexes incorporate thrust sheets of bedrock displaced from a décollement surface more than 100 m below the surface of the foreland fringing the thrust fault margin.…”

Characterization of chlorinated solvent contamination in limestone using innovative FLUTe® technologies in combination with other methods in a line of evidence approach

“…A transition zone of mixed glacial sand/gravel/clay and brecciated (crushed up) limestone, also known as glacitectonite (Pedersen, 2014 and1988), is located between the intact limestone and the clay till. At Naverland, the transition zone is 0.7-1.1 m thick and consists of gravel, sand and brecciated limestone with chert.…”