Tectonic Structure

Tectonic Structure

 

a regularly repeating form of occurrence of rocks in the earth’s crust. In the broad sense, the term “tectonic structure” is applied to various parts of the earth’s crust that are formed by the combination of a number of different smaller structural forms. The most important characteristics for the classification of tectonic structures are scale, morphology, and genesis.

A distinction is made between fundamental structural forms and tectonic structures of magmatic bodies. Fundamental structural forms include layers, folds, joints, and faults (for example, steep faults, slips, overthrusts, and overthrust nappes). Examples of tectonic structures of magmatic bodies are dikes, sills, laccoliths, and batholiths. Such structures of magmatic origin may have structural features of smaller, even microscopic, size.

Regular complexes of fundamental structural forms make up tectonic structures of higher orders. For example, folds are grouped in the compound structural forms called anticlinoria and synclinoria, which in turn form fold systems. Structures found in cratons include syneclises, anteclises, and aulacogens. The largest tectonic structures of the earth’s crust have roots in the upper mantle and are called abyssal, or hypogene, structures. Important examples are cratons and oceanic, geosynclinal, and orogenic mobile belts (seeGEOSYNCLINAL SYSTEM and OROGEN); these structures make up the continental and oceanic segments of the lithosphere. Other abyssal structures include abyssal fractures and rifts. Abyssal structures whose development occurs primarily in the crust are called crustal structures. The formation of tectonic structures is influenced by movements having a certain direction and history (kinematics) of development (see) and by forces that cause tectonic deformations and reflect the dynamics of the process.

Fundamental tectonic structures are studied in structural geology. The microscopic tectonic structures of magmatic bodies are investigated by the methods of microstructural analysis (seePETROTECTONICS). Large-scale complexes of fundamental tectonic structures are studied in geotectonics (see).

REFERENCES

Azhgirei, G. D. Strukturnaia geologiia [2nd ed.]. Moscow, 1966.
Metody izucheniia tektonicheskikh struktur, fascs. 1–2. Moscow, 1960–61.
Khain, V. E. Obshchaia geotektonika, 2nd ed. Moscow, 1973.
Belousov, V. V. Osnovy geotektoniki. Moscow, 1975.
Belousov, V. V. Strukturnaia geologiia, 2nd ed. Moscow, 1971.
Sander, B. Einführung in die Gefügekunde der geologischen Körper, vols. 1–2. Vienna, 1948–50.

G. D. AZHGIREI

References in periodicals archive ?
An early success of the project was identifying an active fault valley east of the Azores and the tectonic structure of a mid-ocean ridge.
According to the rock sound emission test and analysis on homogenization temperature and the tectonic structure of inclusion, the tectonic system in this area was mainly developed during the late Yanshan movement-early Himalayan movement.
The anomalies which were characterized with a large magnetic susceptibility are elongated and correspond to tectonic structure. From the south to the north, two anomaly domains are identified.
It covers the Alps in their plate tectonic framework, the pre-Triassic basement of the Alps, the Alpine domain in the Mesozoic, the Alpine domain in the Cenozoic, the tectonic structure of the Alps, the tectonic evolution of the Alps, and the latest steps in the evolution of the Alps.
The Major active tectonic structure of the area is the Salt Range Thrust (SRT) along which, Palaeozoic rocks are tectonically emplaced over syn- orogenicfranglomerates.
The different field observations and measurements evidenced an active tectonic structure with normal faulting along which a system of travertine was deposited.
This preliminary resource update was made for the purpose of re-estimating the resource numbers and evaluating the tectonic structure of the rocks;
This crossing of boundaries between individual works is underlined by the fact that in some cases the individual pieces themselves display a distinctly tectonic structure. Fock formerly tended to use typography as a basis for his images but now increasingly uses freer gestures.
Architects also drew design inspiration from the shape of the natural environment surrounding it including the crystalline structure of the stones and the mountains tectonic structure. The project will also include advanced environmentally sustainable systems such as on site windmills, hydroponics pools, and rooftop parks; and is expected to be the first carbon neutral building in the region.
Richly arched melody, expansive harmonies and above all a new perception of tectonic structure together constitute the most important musical phenomenon of the romantic epoch and are fully evident in this concerto.
When Crick and Watson in Cambridge, Linus Pauling in America, and the Wilkins Franklin group at King's College London were racing to find the form and structure of DNA, the diagram to emerge--the great diagram of life, a double helix connected by a series of horizontal bridges or rungs--must have proved itself by being (among so many other things) so close to the tectonic structure in Schrodinger's simile of an 'architect's plan and building craft'.
The comparison of the tectonic structure and location of eskers (Karukapp & Tavast 1985) showed that only a few esker systems coincide with the tectonic fault zones.