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A synclinorium (plural synclinoriums or synclinoria) is a large syncline with superimposed smaller folds. [1] Synclines are typically a downward fold ( synform ), termed a synformal syncline (i.e. a trough), but synclines that point upwards can be found when strata have been overturned and folded (an antiformal syncline).
When the limbs of a fold converge upward, the fold is referred to as an antiform. Conversely, when the limbs of a fold converge downward, the fold is known as a synform. Not to be confused with these terms (antiform and synform), the terms anticline and syncline are used in the description of the stratigraphic significance of the fold.
Folds can have a fold axis. A fold axis "is the closest approximation to a straight line that when moved parallel to itself, generates the form of the fold". [2] (Ramsay 1967). A fold that can be generated by a fold axis is called a cylindrical fold. This term has been broadened to include near-cylindrical folds.
Cross-sectional diagram of an anticline Anticline exposed in road cut (small syncline visible at far right). Note the man standing in front of the formation, for scale. New Jersey, U.S. In structural geology, an anticline is a type of fold that is an arch-like shape and has its oldest beds at its core, whereas a syncline is
Also called Indianite. A mineral from the lime-rich end of the plagioclase group of minerals. Anorthites are usually silicates of calcium and aluminium occurring in some basic igneous rocks, typically those produced by the contact metamorphism of impure calcareous sediments. anticline An arched fold in which the layers usually dip away from the fold axis. Contrast syncline. aphanic Having the ...
See the main article on folds for a fuller treatment of fold types and nomenclature but in brief, an anticline is an arch-like fold whereas a syncline is its converse; a downfold. Antiforms, anticlinoria, synforms and synclinoria are variations on these. A monocline (or, rarely, a monoform) is a
Development of a mountain range by sedimentation of a geosyncline and isostatic uplifting. This is the "collapse" of the geosyncline. A geosyncline (originally called a geosynclinal) is an obsolete geological concept to explain orogens, which was developed in the late 19th and early 20th centuries, before the theory of plate tectonics was envisaged.
Chevron folding preferentially occurs when the bedding regularly alternates between contrasting competences. [1] Turbidites, characterized by alternating high-competence sandstones and low-competence shales, provide the typical geological setting for chevron folds to occur. Perpetuation of the fold structure is not geometrically limited.